nelsonj_sce | 4 Oct 03:31 2004
Picon

Re: How to fix a noisy ground?


Hmm...I am going to have to get the schems from Kawai - I will also do
some research on how to filter a ground.  If the analog ground is
noisy the op-amps will by amping noise.  If the digital ground is
noisy, it is possible that the digital chips are actually producing
noise but they "think" they are just producing an accurate digital
signal.  

BTW, last night I replaced IC4 and IC1 (both 064D op-amps) with
Burr-Brown OPA4228.  These are super, super clean op-amps.  They did
improve things, but there is still a lot of noise even with these
great op-amps.  I have designed a headphone amp that uses an OPA4228
and I plan on replacing the LM386 nock off, but I have not built it
yet, I might get to it tonight.  But again I only expect a bit of
improvement because that ground noise will still be there.

Anyway, I have a nice blue backlight, I will soon have a nearly all
Burr-Brown amplification path (at least to my headphones).  If we can
just figure out a way to get the ground noise out, my K5 will look and
 sound killer.  

Must eliminate ground noise, must eliminate ground noise, must...  

--- In k5synth@..., "antdes45dragonmaster" <antdes45 <at> n...>
wrote:
> Digital Ground is plugged to one bridge's negative pole and analog to
> 0v line of the transformer(Black wire). I know it's a noisy ground
> because when I transfer MIDI between K5 and computer, I hear some low
> volume beeps in the noise, and my intermittent inverter whines(Is on
> DGround) in the headphones when it wants. I looked at the schemes, and
(Continue reading)

Cindy and Nathan | 5 Oct 04:17 2004
Picon

Re: Re: How to fix a noisy ground?

Good information, I enjoyed reading it. 
----- Original Message -----
Sent: Sunday, October 03, 2004 8:31 PM
Subject: [k5synth] Re: How to fix a noisy ground?


Hmm...I am going to have to get the schems from Kawai - I will also do
some research on how to filter a ground.  If the analog ground is
noisy the op-amps will by amping noise.  If the digital ground is
noisy, it is possible that the digital chips are actually producing
noise but they "think" they are just producing an accurate digital
signal. 

BTW, last night I replaced IC4 and IC1 (both 064D op-amps) with
Burr-Brown OPA4228.  These are super, super clean op-amps.  They did
improve things, but there is still a lot of noise even with these
great op-amps.  I have designed a headphone amp that uses an OPA4228
and I plan on replacing the LM386 nock off, but I have not built it
yet, I might get to it tonight.  But again I only expect a bit of
improvement because that ground noise will still be there.

Anyway, I have a nice blue backlight, I will soon have a nearly all
Burr-Brown amplification path (at least to my headphones).  If we can
just figure out a way to get the ground noise out, my K5 will look and
sound killer. 

Must eliminate ground noise, must eliminate ground noise, must... 


--- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "antdes45dragonmaster" <antdes45 <at> n...>
wrote:
> Digital Ground is plugged to one bridge's negative pole and analog to
> 0v line of the transformer(Black wire). I know it's a noisy ground
> because when I transfer MIDI between K5 and computer, I hear some low
> volume beeps in the noise, and my intermittent inverter whines(Is on
> DGround) in the headphones when it wants. I looked at the schemes, and
> every different PCB's DGrounds are plugged together on the PSU
> mainboard, but are going to it thru different wires.(Same for
> AGround). Problem is I don't remember how to filter ground. Something
> to try. Also, when I unplug the brown socketed black bus wire going to
> outputs board, there is no signal from the headphones, but still
> noise. So it's not coming from the opamps(Headphones noise). Might be
> that the LM386's ground has no filter. While for the rear outputs
> noise, the opamps might be too noisy(-45dB with some TL072 instead of
> some TL062, which might have not changed anything noise talking, using
> some OPA????, don't remember which, will have to re-find the name on
> DIYAudio, might be a lot less noisy, because a signal passing 4 times
> in pretty noisy OpAmps in series might not be really good).
>
> --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...> wrote:
> > It looks like you have already changed out the op-amps and found that
> > the noise is still there.  Have you tried anythink to fix the noisy
> > ground?  Is it that the digital and analog all share the same ground?
> > Is there a way to "split" the ground or add a new ground plane and
> > reroute say the digital chips to the new ground plane?  Are all the
> > analog parts on a single board so that we could just cut the ground to
> > that board and then wire up a new, "independent" ground?  Are there
> > just a few key digital parts that are creating the noise that can be
> > rerouted to a seperate ground plane?
> >
> > Has anyone at Kawai told you how to solve this problem?  Even if I can
> > get a hold of the schematics, if Kawai or others can identify a few
> > key components it should not be that hard to create a seperate ground
> > for those parts.
> >
> > Any thoughts?
> >
> > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, Antoine Deschênes <antdes45 <at> n...>
wrote:
> > > The LM386 doesn't produce any noise. Even if you unplug the signal
> > there
> > > will still be some. Sctually the problem is a noisy ground. It's
> > sharing
> > > the same ground for all the board(s).
> > >
> > > nelsonj_sce <at> y... a écrit:
> > >
> > > > Here is the latest, it is good news.
> > > >
> > > > Today I got my parts for DigiKey.  As below I replaced my
backlight
> > > > with a blue backlight from nightlaunch.  It worked with my
stock K5
> > > > inverter.  However, my stock inverter was very flakey, even
after I
> > > > did the resolder job so I decided to replace the stock
inverter with
> > > > the DigiKey part.  (Digikey part #289-1032-ND).  The good news
> is that
> > > > inverter works (even though it is only about 95V <at> about
550Hz).  It
> > > > is a slightly different color than before, but it still looks
great.
> > > > Also- THERE IS VIRTUALLY NO HUM!
> > > >
> > > > The only warning is the Digikey part is not the exact same size
> as the
> > > > original inverter - it is a bit smaller in footprint and a lot
> > > > shorter.  The stock inverter has only three connections (in -
out -
> > > > ground) and the new inverter has a fourth pin for mounting.
Because
> > > > the part is smaller, I used the original hole for the "out", but
> I had
> > > > to wire up jumpers to the "ground" and the "in" - not a big
deal but
> > > > it is some extra work  - and you don't want to see pictures of
> my ugly
> > > > job.  :).  But so far so good.
> > > >
> > > > Also, I did the 147K resistor hack and it seems to have gone
> well.  My
> > > > K5 is a louder, but the headphones have even more noise now.
I have
> > > > been looking things over and I think the headphone noise is
because
> > > > they use a cheap LM386 op-amp and a bad overall design for the
> > > > headphone amp.  I am trying to see if I can replace this with a
> better
> > > > op-amp, otherwise I think the only good solution is to just bypass
> > > > their circuit completely and make a better headphone amp and
wire it
> > > > up to the K5.
> > > >
> > > > Anyway, again the good news is that for less than $30
delivered you
> > > > can get nightlaunch backlight and a Digikey inverter and have
a new
> > > > backlight that does not hum!  :) 
> > > >
> > > > Now for the headphone amp...
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...>
> > wrote:
> > > > > Update:
> > > > > Well today I ordered a new inverter from www.DigiKey.com.  I
> > found an
> > > > > inverter that looks like it will do the job - for those
interested
> > > > it is:
> > > > >
> > > > > Digikey part #      289-1032-ND  and it only cost $11.90 - not
> bad.
> > > > >
> > > > > I am not sure if it will fit exactly in the same slots as the
> > original
> > > > > inverter so it might require some additional wiring.
> > > > >
> > > > > Anyway, I had my K5 open to look at the power supply to plan
> the new
> > > > > inverter install when my K5 started "humming", and guess what,
> I now
> > > > > have a beautiful blue backlight.  It looks great, a very cool
> blue.
> > > > > So it appears my inverter was not bad, but it just has bad
solder
> > > > > joints.  It is working for now but tomorrow I will likely take
> > out the
> > > > > board and redo all the solder joints.
> > > > >
> > > > > Just some additional info I learned in researching
backlights and
> > > > > inverters.  The "brightness" of the backlight is a function
of the
> > > > > voltage and frequency applied to the backlight.  It appears one
> > has a
> > > > > lot of flexibility in selecting the inverter output voltage and
> > freq.
> > > > > For example, nightlauch says you can "test" the backlight by
> > plugging
> > > > > it directly in to a wall socket (120V AC <at> 60 Hz here in the
> > US)!  The
> > > > > higher the voltage and freq the brighter the backlight. 
> > However, the
> > > > > backlight will "burn out" quicker the higher the freq.  So there
> > is a
> > > > > trade off, high freq = bright but shorter life.
> > > > >
> > > > > Right now my stock inverter is putting out about 102V <at> 380
Hz.  I
> > > > > think the inverter I ordered will put out about 95V <at> 540 Hz and
> > > > > should work with a 3 - 6 V DC input.
> > > > >
> > > > > Next step, 147k resistors (also ordered from Digikey today).
> > > > >
> > > > >
> > > > >
> > > > > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...>
> > wrote:
> > > > > > Well I replaced my backlight with one I ordered from
> > > > > www.nightlaunch.com.
> > > > > >
> > > > > > It took less than two weeks from when I ordered and the
> parts look
> > > > > good.
> > > > > >
> > > > > > Good news/bad news though on my backlight.
> > > > > >
> > > > > > The good news:  I had no problems removing the LCD, taking out
> > the old
> > > > > > backlight and sliding in the new backlight.  The new light has
> > some
> > > > > > wires and a plastic "tab" that kind of gets in the way, so I
> > soldered
> > > > > > the backlight wires to where the wires connect to the LCD
board.
> > > > > > Hint:You have to cut the new backlight to size, so make the
> > backlight
> > > > > > a little longer (say 1/4 inch) than the original to make
things
> > > > easier.
> > > > > >
> > > > > > Bad news: My backlight does not work but I think my inverter
> > is the
> > > > > > problem.  I am only getting about 1/2 Volt at the output of my
> > > > > > inverter, and I am supposed to get 120V <at> 400Hz if I
> understand the
> > > > > > part correctly.  I tested my inverter before I did the
backlight
> > > > > > install and saw it had low voltage, but I was hoping that my
> > existing
> > > > > > "dead" backlight was causing the problem (i.e. it was
> shorted.) I
> > > > > > guess not because even with the new backlight I get very low
> > voltage.
> > > > > >
> > > > > > Anyway, it looks like I need to get an inverter.  I can get an
> > > > > > inverter from nightlaunch for $17.99+s/h but it needs 9V
DC.  I
> > > > > > understand the inverter in the K5 uses 5V DC.
> > > > > >
> > > > > > Q1: Does the K5 inverter use 5V DC?
> > > > > > Q2: If I measure the voltage on the two wires to the left
of the
> > > > > > inverter, should I get 120V if everything is working? (My
> > Fluke says
> > > > > > it is good <=1kHz)
> > > > > > Q2: Does anyone know where to get a compatible K5 inverter
> and how
> > > > > > much it will cost?
> > > > > >
> > > > > > Thanks again for all the help.  This group is great.
> > > >
> > > >
> > > > Yahoo! Groups Sponsor
> > > > ADVERTISEMENT
> > > >
> >
>
<http://us.ard.yahoo.com/SIG=129jk20o5/M=273541.4247512.5496808.2248467/D=g=
> =
> >
>
rplch/S=1705032144:HM/EXP=1095918198/A=2061551/R=0/SIG=11sr5b9n1/*http://la=
> u=
> > nch.yahoo.com/artist/videos.asp?artistID=1001301>
> >
> > > >
> > > >
> > > >
> > > >
> >
------------------------------------------------------------------------
> > > > Yahoo! Groups Links
> > > >
> > > >     * To visit your group on the web, go to:
> > > >       http://groups.yahoo.com/group/k5synth/
> > > >       
> > > >     * To unsubscribe from this group, send an email to:
> > > >       k5synth-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org
> > > >     
> <mailto:k5synth-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org?subject=Unsubscribe>
> > > >       
> > > >     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> > > >       Service <http://docs.yahoo.com/info/terms/>.
> > > >
> > > >
> > >
> > > --
> > > antdes45 <at> n...




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nelsonj_sce | 5 Oct 06:14 2004
Picon

Re: How to fix a noisy ground?


Antdes,
Good information in the note below.  It sounds like the good news is
that the digital (D) and analog (A) have seperate grounds.  From
everything I have been reading that is good news.  If they had the
same ground on the same PCB we might be completely out of luck.  Today
I ordered the latest OS ROM and schematics from Kawai so hopefully,
once I have the schems, I make more informed suggestions on how to
reduce the ground noise.

I did read something today that said that, although you should have
separate A and D grounding, ultimately both the A and D should be
grounded at the same point.  Otherwise, the D might inject noise in to
the A ground.  Based on your note, this might be just what is going on
in the K5.  

Based on this observation, one thing to try would be to take the D
ground off of the power supply board and connect that ground directly
to the A ground on the transformer.  We need to make sure the power
supply board is still fully grounded even if we remove the D ground,
but you should be able to check the schem and see if it looks like
this is an easy move.

Anyway I don't want to do anything too fancy until I look at the
schems, but if it looks safe, this is the first thing I want to try. 
(Or if you feel adventurous you could try it and tell me if it works!)

Thanks for the note and let me know if you find anything else out. 

--- In k5synth@..., "antdes45dragonmaster" <antdes45 <at> n...>
wrote:
> Digital Ground is plugged to one bridge's negative pole and analog to
> 0v line of the transformer(Black wire). I know it's a noisy ground
> because when I transfer MIDI between K5 and computer, I hear some low
> volume beeps in the noise, and my intermittent inverter whines(Is on
> DGround) in the headphones when it wants. I looked at the schemes, and
> every different PCB's DGrounds are plugged together on the PSU
> mainboard, but are going to it thru different wires.(Same for
> AGround). Problem is I don't remember how to filter ground. Something
> to try. Also, when I unplug the brown socketed black bus wire going to
> outputs board, there is no signal from the headphones, but still
> noise. So it's not coming from the opamps(Headphones noise). Might be
> that the LM386's ground has no filter. While for the rear outputs
> noise, the opamps might be too noisy(-45dB with some TL072 instead of
> some TL062, which might have not changed anything noise talking, using
> some OPA????, don't remember which, will have to re-find the name on
> DIYAudio, might be a lot less noisy, because a signal passing 4 times
> in pretty noisy OpAmps in series might not be really good). 
> 
> --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> wrote:
> > It looks like you have already changed out the op-amps and found that
> > the noise is still there.  Have you tried anythink to fix the noisy
> > ground?  Is it that the digital and analog all share the same ground?
> > Is there a way to "split" the ground or add a new ground plane and
> > reroute say the digital chips to the new ground plane?  Are all the
> > analog parts on a single board so that we could just cut the ground to
> > that board and then wire up a new, "independent" ground?  Are there
> > just a few key digital parts that are creating the noise that can be
> > rerouted to a seperate ground plane? 
> > 
> > Has anyone at Kawai told you how to solve this problem?  Even if I can
> > get a hold of the schematics, if Kawai or others can identify a few
> > key components it should not be that hard to create a seperate ground
> > for those parts.
> > 
> > Any thoughts?
> > 
> > --- In k5synth@..., Antoine Deschênes <antdes45 <at> n...>
wrote:
> > > The LM386 doesn't produce any noise. Even if you unplug the signal
> > there 
> > > will still be some. Sctually the problem is a noisy ground. It's
> > sharing 
> > > the same ground for all the board(s).
> > > 
> > > nelsonj_sce <at> y... a écrit:
> > > 
> > > > Here is the latest, it is good news.
> > > >
> > > > Today I got my parts for DigiKey.  As below I replaced my
backlight
> > > > with a blue backlight from nightlaunch.  It worked with my
stock K5
> > > > inverter.  However, my stock inverter was very flakey, even
after I
> > > > did the resolder job so I decided to replace the stock
inverter with
> > > > the DigiKey part.  (Digikey part #289-1032-ND).  The good news
> is that
> > > > inverter works (even though it is only about 95V  <at>  about
550Hz).  It
> > > > is a slightly different color than before, but it still looks
great.
> > > > Also- THERE IS VIRTUALLY NO HUM! 
> > > >
> > > > The only warning is the Digikey part is not the exact same size
> as the
> > > > original inverter - it is a bit smaller in footprint and a lot
> > > > shorter.  The stock inverter has only three connections (in -
out -
> > > > ground) and the new inverter has a fourth pin for mounting. 
Because
> > > > the part is smaller, I used the original hole for the "out", but
> I had
> > > > to wire up jumpers to the "ground" and the "in" - not a big
deal but
> > > > it is some extra work  - and you don't want to see pictures of
> my ugly
> > > > job.  :).  But so far so good.
> > > >
> > > > Also, I did the 147K resistor hack and it seems to have gone
> well.  My
> > > > K5 is a louder, but the headphones have even more noise now. 
I have
> > > > been looking things over and I think the headphone noise is
because
> > > > they use a cheap LM386 op-amp and a bad overall design for the
> > > > headphone amp.  I am trying to see if I can replace this with a
> better
> > > > op-amp, otherwise I think the only good solution is to just bypass
> > > > their circuit completely and make a better headphone amp and
wire it
> > > > up to the K5.
> > > >
> > > > Anyway, again the good news is that for less than $30
delivered you
> > > > can get nightlaunch backlight and a Digikey inverter and have
a new
> > > > backlight that does not hum!  :)  
> > > >
> > > > Now for the headphone amp...
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...>
> > wrote:
> > > > > Update:
> > > > > Well today I ordered a new inverter from www.DigiKey.com.  I
> > found an
> > > > > inverter that looks like it will do the job - for those
interested
> > > > it is:
> > > > >
> > > > > Digikey part #      289-1032-ND  and it only cost $11.90 - not
> bad.
> > > > >
> > > > > I am not sure if it will fit exactly in the same slots as the
> > original
> > > > > inverter so it might require some additional wiring.
> > > > >
> > > > > Anyway, I had my K5 open to look at the power supply to plan
> the new
> > > > > inverter install when my K5 started "humming", and guess what,
> I now
> > > > > have a beautiful blue backlight.  It looks great, a very cool
> blue.
> > > > > So it appears my inverter was not bad, but it just has bad
solder
> > > > > joints.  It is working for now but tomorrow I will likely take
> > out the
> > > > > board and redo all the solder joints. 
> > > > >
> > > > > Just some additional info I learned in researching
backlights and
> > > > > inverters.  The "brightness" of the backlight is a function
of the
> > > > > voltage and frequency applied to the backlight.  It appears one
> > has a
> > > > > lot of flexibility in selecting the inverter output voltage and
> > freq.
> > > > > For example, nightlauch says you can "test" the backlight by
> > plugging
> > > > > it directly in to a wall socket (120V AC  <at>  60 Hz here in the
> > US)!  The
> > > > > higher the voltage and freq the brighter the backlight.  
> > However, the
> > > > > backlight will "burn out" quicker the higher the freq.  So there
> > is a
> > > > > trade off, high freq = bright but shorter life. 
> > > > >
> > > > > Right now my stock inverter is putting out about 102V  <at>  380
Hz.  I
> > > > > think the inverter I ordered will put out about 95V  <at>  540 Hz and
> > > > > should work with a 3 - 6 V DC input.
> > > > >
> > > > > Next step, 147k resistors (also ordered from Digikey today). 
> > > > >
> > > > >
> > > > >
> > > > > --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...>
> > wrote:
> > > > > > Well I replaced my backlight with one I ordered from
> > > > > www.nightlaunch.com.
> > > > > >
> > > > > > It took less than two weeks from when I ordered and the
> parts look
> > > > > good. 
> > > > > >
> > > > > > Good news/bad news though on my backlight. 
> > > > > >
> > > > > > The good news:  I had no problems removing the LCD, taking out
> > the old
> > > > > > backlight and sliding in the new backlight.  The new light has
> > some
> > > > > > wires and a plastic "tab" that kind of gets in the way, so I
> > soldered
> > > > > > the backlight wires to where the wires connect to the LCD
board.
> > > > > > Hint:You have to cut the new backlight to size, so make the
> > backlight
> > > > > > a little longer (say 1/4 inch) than the original to make
things
> > > > easier.
> > > > > >
> > > > > > Bad news: My backlight does not work but I think my inverter
> > is the
> > > > > > problem.  I am only getting about 1/2 Volt at the output of my
> > > > > > inverter, and I am supposed to get 120V  <at> 400Hz if I
> understand the
> > > > > > part correctly.  I tested my inverter before I did the
backlight
> > > > > > install and saw it had low voltage, but I was hoping that my
> > existing
> > > > > > "dead" backlight was causing the problem (i.e. it was
> shorted.) I
> > > > > > guess not because even with the new backlight I get very low
> > voltage.
> > > > > >
> > > > > > Anyway, it looks like I need to get an inverter.  I can get an
> > > > > > inverter from nightlaunch for $17.99+s/h but it needs 9V
DC.  I
> > > > > > understand the inverter in the K5 uses 5V DC.
> > > > > > 
> > > > > > Q1: Does the K5 inverter use 5V DC?
> > > > > > Q2: If I measure the voltage on the two wires to the left
of the
> > > > > > inverter, should I get 120V if everything is working? (My
> > Fluke says
> > > > > > it is good <=1kHz)
> > > > > > Q2: Does anyone know where to get a compatible K5 inverter
> and how
> > > > > > much it will cost?
> > > > > >
> > > > > > Thanks again for all the help.  This group is great.
> > > >
> > > >
> > > > Yahoo! Groups Sponsor
> > > > ADVERTISEMENT
> > > >
> >
>
<http://us.ard.yahoo.com/SIG=129jk20o5/M=273541.4247512.5496808.2248467/D=g=
> =
> >
>
rplch/S=1705032144:HM/EXP=1095918198/A=2061551/R=0/SIG=11sr5b9n1/*http://la=
> u=
> > nch.yahoo.com/artist/videos.asp?artistID=1001301>
> > 
> > > >
> > > >
> > > >
> > > >
> >
------------------------------------------------------------------------
> > > > Yahoo! Groups Links
> > > >
> > > >     * To visit your group on the web, go to:
> > > >       http://groups.yahoo.com/group/k5synth/
> > > >        
> > > >     * To unsubscribe from this group, send an email to:
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> <mailto:k5synth-unsubscribe@...?subject=Unsubscribe>
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> > > 
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> > > antdes45 <at> n...

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antdes45dragonmaster | 7 Oct 15:49 2004
Picon

Re: How to fix a noisy ground?


Buzzing in rear out is signal ground noise, all pcbs have sepparate 
analog grounds to PSU but linked together on the psu.

--- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> 
wrote:
> 
> Antdes,
> Good information in the note below.  It sounds like the good news is
> that the digital (D) and analog (A) have seperate grounds.  From
> everything I have been reading that is good news.  If they had the
> same ground on the same PCB we might be completely out of luck.  
Today
> I ordered the latest OS ROM and schematics from Kawai so hopefully,
> once I have the schems, I make more informed suggestions on how to
> reduce the ground noise.
> 
> I did read something today that said that, although you should have
> separate A and D grounding, ultimately both the A and D should be
> grounded at the same point.  Otherwise, the D might inject noise in 
to
> the A ground.  Based on your note, this might be just what is going 
on
> in the K5.  
> 
> Based on this observation, one thing to try would be to take the D
> ground off of the power supply board and connect that ground 
directly
> to the A ground on the transformer.  We need to make sure the power
> supply board is still fully grounded even if we remove the D ground,
> but you should be able to check the schem and see if it looks like
> this is an easy move.
> 
> Anyway I don't want to do anything too fancy until I look at the
> schems, but if it looks safe, this is the first thing I want to 
try. 
> (Or if you feel adventurous you could try it and tell me if it 
works!)
> 
> Thanks for the note and let me know if you find anything else out. 
> 
>        
> 
> 
> 
> --- In k5synth@..., "antdes45dragonmaster" 
<antdes45 <at> n...>
> wrote:
> > Digital Ground is plugged to one bridge's negative pole and 
analog to
> > 0v line of the transformer(Black wire). I know it's a noisy ground
> > because when I transfer MIDI between K5 and computer, I hear some 
low
> > volume beeps in the noise, and my intermittent inverter whines(Is 
on
> > DGround) in the headphones when it wants. I looked at the 
schemes, and
> > every different PCB's DGrounds are plugged together on the PSU
> > mainboard, but are going to it thru different wires.(Same for
> > AGround). Problem is I don't remember how to filter ground. 
Something
> > to try. Also, when I unplug the brown socketed black bus wire 
going to
> > outputs board, there is no signal from the headphones, but still
> > noise. So it's not coming from the opamps(Headphones noise). 
Might be
> > that the LM386's ground has no filter. While for the rear outputs
> > noise, the opamps might be too noisy(-45dB with some TL072 
instead of
> > some TL062, which might have not changed anything noise talking, 
using
> > some OPA????, don't remember which, will have to re-find the name 
on
> > DIYAudio, might be a lot less noisy, because a signal passing 4 
times
> > in pretty noisy OpAmps in series might not be really good). 
> > 
> > --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> 
wrote:
> > > It looks like you have already changed out the op-amps and 
found that
> > > the noise is still there.  Have you tried anythink to fix the 
noisy
> > > ground?  Is it that the digital and analog all share the same 
ground?
> > > Is there a way to "split" the ground or add a new ground plane 
and
> > > reroute say the digital chips to the new ground plane?  Are all 
the
> > > analog parts on a single board so that we could just cut the 
ground to
> > > that board and then wire up a new, "independent" ground?  Are 
there
> > > just a few key digital parts that are creating the noise that 
can be
> > > rerouted to a seperate ground plane? 
> > > 
> > > Has anyone at Kawai told you how to solve this problem?  Even 
if I can
> > > get a hold of the schematics, if Kawai or others can identify a 
few
> > > key components it should not be that hard to create a seperate 
ground
> > > for those parts.
> > > 
> > > Any thoughts?
> > > 
> > > --- In k5synth@..., Antoine Deschênes 
<antdes45 <at> n...>
> wrote:
> > > > The LM386 doesn't produce any noise. Even if you unplug the 
signal
> > > there 
> > > > will still be some. Sctually the problem is a noisy ground. 
It's
> > > sharing 
> > > > the same ground for all the board(s).
> > > > 
> > > > nelsonj_sce <at> y... a écrit:
> > > > 
> > > > > Here is the latest, it is good news.
> > > > >
> > > > > Today I got my parts for DigiKey.  As below I replaced my
> backlight
> > > > > with a blue backlight from nightlaunch.  It worked with my
> stock K5
> > > > > inverter.  However, my stock inverter was very flakey, even
> after I
> > > > > did the resolder job so I decided to replace the stock
> inverter with
> > > > > the DigiKey part.  (Digikey part #289-1032-ND).  The good 
news
> > is that
> > > > > inverter works (even though it is only about 95V  <at>  about
> 550Hz).  It
> > > > > is a slightly different color than before, but it still 
looks
> great.
> > > > > Also- THERE IS VIRTUALLY NO HUM! 
> > > > >
> > > > > The only warning is the Digikey part is not the exact same 
size
> > as the
> > > > > original inverter - it is a bit smaller in footprint and a 
lot
> > > > > shorter.  The stock inverter has only three connections 
(in -
> out -
> > > > > ground) and the new inverter has a fourth pin for mounting. 
> Because
> > > > > the part is smaller, I used the original hole for 
the "out", but
> > I had
> > > > > to wire up jumpers to the "ground" and the "in" - not a big
> deal but
> > > > > it is some extra work  - and you don't want to see pictures 
of
> > my ugly
> > > > > job.  :).  But so far so good.
> > > > >
> > > > > Also, I did the 147K resistor hack and it seems to have gone
> > well.  My
> > > > > K5 is a louder, but the headphones have even more noise 
now. 
> I have
> > > > > been looking things over and I think the headphone noise is
> because
> > > > > they use a cheap LM386 op-amp and a bad overall design for 
the
> > > > > headphone amp.  I am trying to see if I can replace this 
with a
> > better
> > > > > op-amp, otherwise I think the only good solution is to just 
bypass
> > > > > their circuit completely and make a better headphone amp and
> wire it
> > > > > up to the K5.
> > > > >
> > > > > Anyway, again the good news is that for less than $30
> delivered you
> > > > > can get nightlaunch backlight and a Digikey inverter and 
have
> a new
> > > > > backlight that does not hum!  :)  
> > > > >
> > > > > Now for the headphone amp...
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --- In k5synth@..., "nelsonj_sce" 
<nelsonj_sce <at> y...>
> > > wrote:
> > > > > > Update:
> > > > > > Well today I ordered a new inverter from 
www.DigiKey.com.  I
> > > found an
> > > > > > inverter that looks like it will do the job - for those
> interested
> > > > > it is:
> > > > > >
> > > > > > Digikey part #      289-1032-ND  and it only cost $11.90 -
 not
> > bad.
> > > > > >
> > > > > > I am not sure if it will fit exactly in the same slots as 
the
> > > original
> > > > > > inverter so it might require some additional wiring.
> > > > > >
> > > > > > Anyway, I had my K5 open to look at the power supply to 
plan
> > the new
> > > > > > inverter install when my K5 started "humming", and guess 
what,
> > I now
> > > > > > have a beautiful blue backlight.  It looks great, a very 
cool
> > blue.
> > > > > > So it appears my inverter was not bad, but it just has bad
> solder
> > > > > > joints.  It is working for now but tomorrow I will likely 
take
> > > out the
> > > > > > board and redo all the solder joints. 
> > > > > >
> > > > > > Just some additional info I learned in researching
> backlights and
> > > > > > inverters.  The "brightness" of the backlight is a 
function
> of the
> > > > > > voltage and frequency applied to the backlight.  It 
appears one
> > > has a
> > > > > > lot of flexibility in selecting the inverter output 
voltage and
> > > freq.
> > > > > > For example, nightlauch says you can "test" the backlight 
by
> > > plugging
> > > > > > it directly in to a wall socket (120V AC  <at>  60 Hz here in 
the
> > > US)!  The
> > > > > > higher the voltage and freq the brighter the backlight.  
> > > However, the
> > > > > > backlight will "burn out" quicker the higher the freq.  
So there
> > > is a
> > > > > > trade off, high freq = bright but shorter life. 
> > > > > >
> > > > > > Right now my stock inverter is putting out about 102V  <at>  
380
> Hz.  I
> > > > > > think the inverter I ordered will put out about 95V  <at>  540 
Hz and
> > > > > > should work with a 3 - 6 V DC input.
> > > > > >
> > > > > > Next step, 147k resistors (also ordered from Digikey 
today). 
> > > > > >
> > > > > >
> > > > > >
> > > > > > --- In k5synth@..., "nelsonj_sce" 
<nelsonj_sce <at> y...>
> > > wrote:
> > > > > > > Well I replaced my backlight with one I ordered from
> > > > > > www.nightlaunch.com.
> > > > > > >
> > > > > > > It took less than two weeks from when I ordered and the
> > parts look
> > > > > > good. 
> > > > > > >
> > > > > > > Good news/bad news though on my backlight. 
> > > > > > >
> > > > > > > The good news:  I had no problems removing the LCD, 
taking out
> > > the old
> > > > > > > backlight and sliding in the new backlight.  The new 
light has
> > > some
> > > > > > > wires and a plastic "tab" that kind of gets in the way, 
so I
> > > soldered
> > > > > > > the backlight wires to where the wires connect to the 
LCD
> board.
> > > > > > > Hint:You have to cut the new backlight to size, so make 
the
> > > backlight
> > > > > > > a little longer (say 1/4 inch) than the original to make
> things
> > > > > easier.
> > > > > > >
> > > > > > > Bad news: My backlight does not work but I think my 
inverter
> > > is the
> > > > > > > problem.  I am only getting about 1/2 Volt at the 
output of my
> > > > > > > inverter, and I am supposed to get 120V  <at> 400Hz if I
> > understand the
> > > > > > > part correctly.  I tested my inverter before I did the
> backlight
> > > > > > > install and saw it had low voltage, but I was hoping 
that my
> > > existing
> > > > > > > "dead" backlight was causing the problem (i.e. it was
> > shorted.) I
> > > > > > > guess not because even with the new backlight I get 
very low
> > > voltage.
> > > > > > >
> > > > > > > Anyway, it looks like I need to get an inverter.  I can 
get an
> > > > > > > inverter from nightlaunch for $17.99+s/h but it needs 9V
> DC.  I
> > > > > > > understand the inverter in the K5 uses 5V DC.
> > > > > > > 
> > > > > > > Q1: Does the K5 inverter use 5V DC?
> > > > > > > Q2: If I measure the voltage on the two wires to the 
left
> of the
> > > > > > > inverter, should I get 120V if everything is working? 
(My
> > > Fluke says
> > > > > > > it is good <=1kHz)
> > > > > > > Q2: Does anyone know where to get a compatible K5 
inverter
> > and how
> > > > > > > much it will cost?
> > > > > > >
> > > > > > > Thanks again for all the help.  This group is great.
> > > > >
> > > > >
> > > > > Yahoo! Groups Sponsor
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> > > > >
> > >
> >
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> > =
> > >
> >
> 
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://la=
> > u=
> > > nch.yahoo.com/artist/videos.asp?artistID=1001301>
> > > 
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> --------------------------------------------------------------------
----
> > > > > Yahoo! Groups Links
> > > > >
> > > > >     * To visit your group on the web, go to:
> > > > >       http://groups.yahoo.com/group/k5synth/
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> > > > >       k5synth-unsubscribe@...
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> > <mailto:k5synth-unsubscribe@...?subject=Unsubscribe>
> > > > >        
> > > > >     * Your use of Yahoo! Groups is subject to the Yahoo! 
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> > > > >
> > > > >
> > > > 
> > > > -- 
> > > > antdes45 <at> n...

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Antoine Deschênes | 7 Oct 17:38 2004
Picon

Re: Re: How to fix a noisy ground?

Note: Digital ground is on bridge neg. and Analog on 0v, and bridge goes to the transformer, so it's connected together in a kind of way.

antdes45-VsqqI1RANlHk1uMJSBkQmQ@public.gmane.org a écrit:

Buzzing in rear out is signal ground noise, all pcbs have sepparate
analog grounds to PSU but linked together on the psu.

--- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...>
wrote:
>
> Antdes,
> Good information in the note below.  It sounds like the good news is
> that the digital (D) and analog (A) have seperate grounds.  From
> everything I have been reading that is good news.  If they had the
> same ground on the same PCB we might be completely out of luck. 
Today
> I ordered the latest OS ROM and schematics from Kawai so hopefully,
> once I have the schems, I make more informed suggestions on how to
> reduce the ground noise.
>
> I did read something today that said that, although you should have
> separate A and D grounding, ultimately both the A and D should be
> grounded at the same point.  Otherwise, the D might inject noise in
to
> the A ground.  Based on your note, this might be just what is going
on
> in the K5. 
>
> Based on this observation, one thing to try would be to take the D
> ground off of the power supply board and connect that ground
directly
> to the A ground on the transformer.  We need to make sure the power
> supply board is still fully grounded even if we remove the D ground,
> but you should be able to check the schem and see if it looks like
> this is an easy move.
>
> Anyway I don't want to do anything too fancy until I look at the
> schems, but if it looks safe, this is the first thing I want to
try.
> (Or if you feel adventurous you could try it and tell me if it
works!)
>
> Thanks for the note and let me know if you find anything else out.
>
>       
>
>
>
> --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "antdes45dragonmaster"
<antdes45 <at> n...>
> wrote:
> > Digital Ground is plugged to one bridge's negative pole and
analog to
> > 0v line of the transformer(Black wire). I know it's a noisy ground
> > because when I transfer MIDI between K5 and computer, I hear some
low
> > volume beeps in the noise, and my intermittent inverter whines(Is
on
> > DGround) in the headphones when it wants. I looked at the
schemes, and
> > every different PCB's DGrounds are plugged together on the PSU
> > mainboard, but are going to it thru different wires.(Same for
> > AGround). Problem is I don't remember how to filter ground.
Something
> > to try. Also, when I unplug the brown socketed black bus wire
going to
> > outputs board, there is no signal from the headphones, but still
> > noise. So it's not coming from the opamps(Headphones noise).
Might be
> > that the LM386's ground has no filter. While for the rear outputs
> > noise, the opamps might be too noisy(-45dB with some TL072
instead of
> > some TL062, which might have not changed anything noise talking,
using
> > some OPA????, don't remember which, will have to re-find the name
on
> > DIYAudio, might be a lot less noisy, because a signal passing 4
times
> > in pretty noisy OpAmps in series might not be really good).
> >
> > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...>
wrote:
> > > It looks like you have already changed out the op-amps and
found that
> > > the noise is still there.  Have you tried anythink to fix the
noisy
> > > ground?  Is it that the digital and analog all share the same
ground?
> > > Is there a way to "split" the ground or add a new ground plane
and
> > > reroute say the digital chips to the new ground plane?  Are all
the
> > > analog parts on a single board so that we could just cut the
ground to
> > > that board and then wire up a new, "independent" ground?  Are
there
> > > just a few key digital parts that are creating the noise that
can be
> > > rerouted to a seperate ground plane?
> > >
> > > Has anyone at Kawai told you how to solve this problem?  Even
if I can
> > > get a hold of the schematics, if Kawai or others can identify a
few
> > > key components it should not be that hard to create a seperate
ground
> > > for those parts.
> > >
> > > Any thoughts?
> > >
> > > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, Antoine Deschênes
<antdes45 <at> n...>
> wrote:
> > > > The LM386 doesn't produce any noise. Even if you unplug the
signal
> > > there
> > > > will still be some. Sctually the problem is a noisy ground.
It's
> > > sharing
> > > > the same ground for all the board(s).
> > > >
> > > > nelsonj_sce <at> y... a écrit:
> > > >
> > > > > Here is the latest, it is good news.
> > > > >
> > > > > Today I got my parts for DigiKey.  As below I replaced my
> backlight
> > > > > with a blue backlight from nightlaunch.  It worked with my
> stock K5
> > > > > inverter.  However, my stock inverter was very flakey, even
> after I
> > > > > did the resolder job so I decided to replace the stock
> inverter with
> > > > > the DigiKey part.  (Digikey part #289-1032-ND).  The good
news
> > is that
> > > > > inverter works (even though it is only about 95V <at> about
> 550Hz).  It
> > > > > is a slightly different color than before, but it still
looks
> great.
> > > > > Also- THERE IS VIRTUALLY NO HUM!
> > > > >
> > > > > The only warning is the Digikey part is not the exact same
size
> > as the
> > > > > original inverter - it is a bit smaller in footprint and a
lot
> > > > > shorter.  The stock inverter has only three connections
(in -
> out -
> > > > > ground) and the new inverter has a fourth pin for mounting.
> Because
> > > > > the part is smaller, I used the original hole for
the "out", but
> > I had
> > > > > to wire up jumpers to the "ground" and the "in" - not a big
> deal but
> > > > > it is some extra work  - and you don't want to see pictures
of
> > my ugly
> > > > > job.  :).  But so far so good.
> > > > >
> > > > > Also, I did the 147K resistor hack and it seems to have gone
> > well.  My
> > > > > K5 is a louder, but the headphones have even more noise
now.
> I have
> > > > > been looking things over and I think the headphone noise is
> because
> > > > > they use a cheap LM386 op-amp and a bad overall design for
the
> > > > > headphone amp.  I am trying to see if I can replace this
with a
> > better
> > > > > op-amp, otherwise I think the only good solution is to just
bypass
> > > > > their circuit completely and make a better headphone amp and
> wire it
> > > > > up to the K5.
> > > > >
> > > > > Anyway, again the good news is that for less than $30
> delivered you
> > > > > can get nightlaunch backlight and a Digikey inverter and
have
> a new
> > > > > backlight that does not hum!  :) 
> > > > >
> > > > > Now for the headphone amp...
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce"
<nelsonj_sce <at> y...>
> > > wrote:
> > > > > > Update:
> > > > > > Well today I ordered a new inverter from
www.DigiKey.com.  I
> > > found an
> > > > > > inverter that looks like it will do the job - for those
> interested
> > > > > it is:
> > > > > >
> > > > > > Digikey part #      289-1032-ND  and it only cost $11.90 -
not
> > bad.
> > > > > >
> > > > > > I am not sure if it will fit exactly in the same slots as
the
> > > original
> > > > > > inverter so it might require some additional wiring.
> > > > > >
> > > > > > Anyway, I had my K5 open to look at the power supply to
plan
> > the new
> > > > > > inverter install when my K5 started "humming", and guess
what,
> > I now
> > > > > > have a beautiful blue backlight.  It looks great, a very
cool
> > blue.
> > > > > > So it appears my inverter was not bad, but it just has bad
> solder
> > > > > > joints.  It is working for now but tomorrow I will likely
take
> > > out the
> > > > > > board and redo all the solder joints.
> > > > > >
> > > > > > Just some additional info I learned in researching
> backlights and
> > > > > > inverters.  The "brightness" of the backlight is a
function
> of the
> > > > > > voltage and frequency applied to the backlight.  It
appears one
> > > has a
> > > > > > lot of flexibility in selecting the inverter output
voltage and
> > > freq.
> > > > > > For example, nightlauch says you can "test" the backlight
by
> > > plugging
> > > > > > it directly in to a wall socket (120V AC <at> 60 Hz here in
the
> > > US)!  The
> > > > > > higher the voltage and freq the brighter the backlight. 
> > > However, the
> > > > > > backlight will "burn out" quicker the higher the freq. 
So there
> > > is a
> > > > > > trade off, high freq = bright but shorter life.
> > > > > >
> > > > > > Right now my stock inverter is putting out about 102V <at>
380
> Hz.  I
> > > > > > think the inverter I ordered will put out about 95V <at> 540
Hz and
> > > > > > should work with a 3 - 6 V DC input.
> > > > > >
> > > > > > Next step, 147k resistors (also ordered from Digikey
today).
> > > > > >
> > > > > >
> > > > > >
> > > > > > --- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce"
<nelsonj_sce <at> y...>
> > > wrote:
> > > > > > > Well I replaced my backlight with one I ordered from
> > > > > > www.nightlaunch.com.
> > > > > > >
> > > > > > > It took less than two weeks from when I ordered and the
> > parts look
> > > > > > good.
> > > > > > >
> > > > > > > Good news/bad news though on my backlight.
> > > > > > >
> > > > > > > The good news:  I had no problems removing the LCD,
taking out
> > > the old
> > > > > > > backlight and sliding in the new backlight.  The new
light has
> > > some
> > > > > > > wires and a plastic "tab" that kind of gets in the way,
so I
> > > soldered
> > > > > > > the backlight wires to where the wires connect to the
LCD
> board.
> > > > > > > Hint:You have to cut the new backlight to size, so make
the
> > > backlight
> > > > > > > a little longer (say 1/4 inch) than the original to make
> things
> > > > > easier.
> > > > > > >
> > > > > > > Bad news: My backlight does not work but I think my
inverter
> > > is the
> > > > > > > problem.  I am only getting about 1/2 Volt at the
output of my
> > > > > > > inverter, and I am supposed to get 120V <at> 400Hz if I
> > understand the
> > > > > > > part correctly.  I tested my inverter before I did the
> backlight
> > > > > > > install and saw it had low voltage, but I was hoping
that my
> > > existing
> > > > > > > "dead" backlight was causing the problem (i.e. it was
> > shorted.) I
> > > > > > > guess not because even with the new backlight I get
very low
> > > voltage.
> > > > > > >
> > > > > > > Anyway, it looks like I need to get an inverter.  I can
get an
> > > > > > > inverter from nightlaunch for $17.99+s/h but it needs 9V
> DC.  I
> > > > > > > understand the inverter in the K5 uses 5V DC.
> > > > > > >
> > > > > > > Q1: Does the K5 inverter use 5V DC?
> > > > > > > Q2: If I measure the voltage on the two wires to the
left
> of the
> > > > > > > inverter, should I get 120V if everything is working?
(My
> > > Fluke says
> > > > > > > it is good <=1kHz)
> > > > > > > Q2: Does anyone know where to get a compatible K5
inverter
> > and how
> > > > > > > much it will cost?
> > > > > > >
> > > > > > > Thanks again for all the help.  This group is great.
> > > > >
> > > > >
> > > > > Yahoo! Groups Sponsor
> > > > > ADVERTISEMENT
> > > > >
> > >
> >
>
<http://us.ard.yahoo.com/SIG=129jk20o5/M=273541.4247512.5496808.224846
7/D=g=
> > =
> > >
> >
>
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://la=
> > u=
> > > nch.yahoo.com/artist/videos.asp?artistID=1001301>
> > >
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> --------------------------------------------------------------------
----
> > > > > Yahoo! Groups Links
> > > > >
> > > > >     * To visit your group on the web, go to:
> > > > >       http://groups.yahoo.com/group/k5synth/
> > > > >       
> > > > >     * To unsubscribe from this group, send an email to:
> > > > >       k5synth-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org
> > > > >     
> > <mailto:k5synth-unsubscribe-hHKSG33TihhbjbujkaE4pw@public.gmane.org?subject=Unsubscribe>
> > > > >       
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> > > > >
> > > > >
> > > >
> > > > --
> > > > antdes45 <at> n...






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nelsonj_sce | 9 Oct 08:34 2004
Picon

Re: How to fix a noisy ground?


I got the schems yesterday and I will take a look at the ground issue.    
Although all grounds will eventually get to a single point, one idea
is to make sure the D and A get to the same ground at the same time -
that is make sure there is no path between the A and D grounds. 
Anyway, I will try to look at the schems this weekend.

I also just upgraded to OS1.2.  I am a bit disappointed that the
Kfuenf editor still does not work for me.  Oh well, more on that in my
next post.  

Also, I hooked up my J-station to the K5.  The J-station has a very
good noise gate, as well as delay+reverb+chorus(ect).  I have to crank
the noise gate up to about 65 to kill the line noise.  But the K5
sounds great through this unit and I recommend it if you happen to
have a J-station around. 
--- In k5synth@..., "antdes45dragonmaster" <antdes45 <at> n...>
wrote:
> 
> Buzzing in rear out is signal ground noise, all pcbs have sepparate 
> analog grounds to PSU but linked together on the psu.
> 
> --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> 
> wrote:
> > 
> > Antdes,
> > Good information in the note below.  It sounds like the good news is
> > that the digital (D) and analog (A) have seperate grounds.  From
> > everything I have been reading that is good news.  If they had the
> > same ground on the same PCB we might be completely out of luck.  
> Today
> > I ordered the latest OS ROM and schematics from Kawai so hopefully,
> > once I have the schems, I make more informed suggestions on how to
> > reduce the ground noise.
> > 
> > I did read something today that said that, although you should have
> > separate A and D grounding, ultimately both the A and D should be
> > grounded at the same point.  Otherwise, the D might inject noise in 
> to
> > the A ground.  Based on your note, this might be just what is going 
> on
> > in the K5.  
> > 
> > Based on this observation, one thing to try would be to take the D
> > ground off of the power supply board and connect that ground 
> directly
> > to the A ground on the transformer.  We need to make sure the power
> > supply board is still fully grounded even if we remove the D ground,
> > but you should be able to check the schem and see if it looks like
> > this is an easy move.
> > 
> > Anyway I don't want to do anything too fancy until I look at the
> > schems, but if it looks safe, this is the first thing I want to 
> try. 
> > (Or if you feel adventurous you could try it and tell me if it 
> works!)
> > 
> > Thanks for the note and let me know if you find anything else out. 
> > 
> >        
> > 
> > 
> > 
> > --- In k5synth@..., "antdes45dragonmaster" 
> <antdes45 <at> n...>
> > wrote:
> > > Digital Ground is plugged to one bridge's negative pole and 
> analog to
> > > 0v line of the transformer(Black wire). I know it's a noisy ground
> > > because when I transfer MIDI between K5 and computer, I hear some 
> low
> > > volume beeps in the noise, and my intermittent inverter whines(Is 
> on
> > > DGround) in the headphones when it wants. I looked at the 
> schemes, and
> > > every different PCB's DGrounds are plugged together on the PSU
> > > mainboard, but are going to it thru different wires.(Same for
> > > AGround). Problem is I don't remember how to filter ground. 
> Something
> > > to try. Also, when I unplug the brown socketed black bus wire 
> going to
> > > outputs board, there is no signal from the headphones, but still
> > > noise. So it's not coming from the opamps(Headphones noise). 
> Might be
> > > that the LM386's ground has no filter. While for the rear outputs
> > > noise, the opamps might be too noisy(-45dB with some TL072 
> instead of
> > > some TL062, which might have not changed anything noise talking, 
> using
> > > some OPA????, don't remember which, will have to re-find the name 
> on
> > > DIYAudio, might be a lot less noisy, because a signal passing 4 
> times
> > > in pretty noisy OpAmps in series might not be really good). 
> > > 
> > > --- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> 
> wrote:
> > > > It looks like you have already changed out the op-amps and 
> found that
> > > > the noise is still there.  Have you tried anythink to fix the 
> noisy
> > > > ground?  Is it that the digital and analog all share the same 
> ground?
> > > > Is there a way to "split" the ground or add a new ground plane 
> and
> > > > reroute say the digital chips to the new ground plane?  Are all 
> the
> > > > analog parts on a single board so that we could just cut the 
> ground to
> > > > that board and then wire up a new, "independent" ground?  Are 
> there
> > > > just a few key digital parts that are creating the noise that 
> can be
> > > > rerouted to a seperate ground plane? 
> > > > 
> > > > Has anyone at Kawai told you how to solve this problem?  Even 
> if I can
> > > > get a hold of the schematics, if Kawai or others can identify a 
> few
> > > > key components it should not be that hard to create a seperate 
> ground
> > > > for those parts.
> > > > 
> > > > Any thoughts?
> > > > 
> > > > --- In k5synth@..., Antoine Deschênes 
> <antdes45 <at> n...>
> > wrote:
> > > > > The LM386 doesn't produce any noise. Even if you unplug the 
> signal
> > > > there 
> > > > > will still be some. Sctually the problem is a noisy ground. 
> It's
> > > > sharing 
> > > > > the same ground for all the board(s).
> > > > > 
> > > > > nelsonj_sce <at> y... a écrit:
> > > > > 
> > > > > > Here is the latest, it is good news.
> > > > > >
> > > > > > Today I got my parts for DigiKey.  As below I replaced my
> > backlight
> > > > > > with a blue backlight from nightlaunch.  It worked with my
> > stock K5
> > > > > > inverter.  However, my stock inverter was very flakey, even
> > after I
> > > > > > did the resolder job so I decided to replace the stock
> > inverter with
> > > > > > the DigiKey part.  (Digikey part #289-1032-ND).  The good 
> news
> > > is that
> > > > > > inverter works (even though it is only about 95V  <at>  about
> > 550Hz).  It
> > > > > > is a slightly different color than before, but it still 
> looks
> > great.
> > > > > > Also- THERE IS VIRTUALLY NO HUM! 
> > > > > >
> > > > > > The only warning is the Digikey part is not the exact same 
> size
> > > as the
> > > > > > original inverter - it is a bit smaller in footprint and a 
> lot
> > > > > > shorter.  The stock inverter has only three connections 
> (in -
> > out -
> > > > > > ground) and the new inverter has a fourth pin for mounting. 
> > Because
> > > > > > the part is smaller, I used the original hole for 
> the "out", but
> > > I had
> > > > > > to wire up jumpers to the "ground" and the "in" - not a big
> > deal but
> > > > > > it is some extra work  - and you don't want to see pictures 
> of
> > > my ugly
> > > > > > job.  :).  But so far so good.
> > > > > >
> > > > > > Also, I did the 147K resistor hack and it seems to have gone
> > > well.  My
> > > > > > K5 is a louder, but the headphones have even more noise 
> now. 
> > I have
> > > > > > been looking things over and I think the headphone noise is
> > because
> > > > > > they use a cheap LM386 op-amp and a bad overall design for 
> the
> > > > > > headphone amp.  I am trying to see if I can replace this 
> with a
> > > better
> > > > > > op-amp, otherwise I think the only good solution is to just 
> bypass
> > > > > > their circuit completely and make a better headphone amp and
> > wire it
> > > > > > up to the K5.
> > > > > >
> > > > > > Anyway, again the good news is that for less than $30
> > delivered you
> > > > > > can get nightlaunch backlight and a Digikey inverter and 
> have
> > a new
> > > > > > backlight that does not hum!  :)  
> > > > > >
> > > > > > Now for the headphone amp...
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > --- In k5synth@..., "nelsonj_sce" 
> <nelsonj_sce <at> y...>
> > > > wrote:
> > > > > > > Update:
> > > > > > > Well today I ordered a new inverter from 
> www.DigiKey.com.  I
> > > > found an
> > > > > > > inverter that looks like it will do the job - for those
> > interested
> > > > > > it is:
> > > > > > >
> > > > > > > Digikey part #      289-1032-ND  and it only cost $11.90 -
>  not
> > > bad.
> > > > > > >
> > > > > > > I am not sure if it will fit exactly in the same slots as 
> the
> > > > original
> > > > > > > inverter so it might require some additional wiring.
> > > > > > >
> > > > > > > Anyway, I had my K5 open to look at the power supply to 
> plan
> > > the new
> > > > > > > inverter install when my K5 started "humming", and guess 
> what,
> > > I now
> > > > > > > have a beautiful blue backlight.  It looks great, a very 
> cool
> > > blue.
> > > > > > > So it appears my inverter was not bad, but it just has bad
> > solder
> > > > > > > joints.  It is working for now but tomorrow I will likely 
> take
> > > > out the
> > > > > > > board and redo all the solder joints. 
> > > > > > >
> > > > > > > Just some additional info I learned in researching
> > backlights and
> > > > > > > inverters.  The "brightness" of the backlight is a 
> function
> > of the
> > > > > > > voltage and frequency applied to the backlight.  It 
> appears one
> > > > has a
> > > > > > > lot of flexibility in selecting the inverter output 
> voltage and
> > > > freq.
> > > > > > > For example, nightlauch says you can "test" the backlight 
> by
> > > > plugging
> > > > > > > it directly in to a wall socket (120V AC  <at>  60 Hz here in 
> the
> > > > US)!  The
> > > > > > > higher the voltage and freq the brighter the backlight.  
> > > > However, the
> > > > > > > backlight will "burn out" quicker the higher the freq.  
> So there
> > > > is a
> > > > > > > trade off, high freq = bright but shorter life. 
> > > > > > >
> > > > > > > Right now my stock inverter is putting out about 102V  <at>  
> 380
> > Hz.  I
> > > > > > > think the inverter I ordered will put out about 95V  <at>  540 
> Hz and
> > > > > > > should work with a 3 - 6 V DC input.
> > > > > > >
> > > > > > > Next step, 147k resistors (also ordered from Digikey 
> today). 
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > --- In k5synth@..., "nelsonj_sce" 
> <nelsonj_sce <at> y...>
> > > > wrote:
> > > > > > > > Well I replaced my backlight with one I ordered from
> > > > > > > www.nightlaunch.com.
> > > > > > > >
> > > > > > > > It took less than two weeks from when I ordered and the
> > > parts look
> > > > > > > good. 
> > > > > > > >
> > > > > > > > Good news/bad news though on my backlight. 
> > > > > > > >
> > > > > > > > The good news:  I had no problems removing the LCD, 
> taking out
> > > > the old
> > > > > > > > backlight and sliding in the new backlight.  The new 
> light has
> > > > some
> > > > > > > > wires and a plastic "tab" that kind of gets in the way, 
> so I
> > > > soldered
> > > > > > > > the backlight wires to where the wires connect to the 
> LCD
> > board.
> > > > > > > > Hint:You have to cut the new backlight to size, so make 
> the
> > > > backlight
> > > > > > > > a little longer (say 1/4 inch) than the original to make
> > things
> > > > > > easier.
> > > > > > > >
> > > > > > > > Bad news: My backlight does not work but I think my 
> inverter
> > > > is the
> > > > > > > > problem.  I am only getting about 1/2 Volt at the 
> output of my
> > > > > > > > inverter, and I am supposed to get 120V  <at> 400Hz if I
> > > understand the
> > > > > > > > part correctly.  I tested my inverter before I did the
> > backlight
> > > > > > > > install and saw it had low voltage, but I was hoping 
> that my
> > > > existing
> > > > > > > > "dead" backlight was causing the problem (i.e. it was
> > > shorted.) I
> > > > > > > > guess not because even with the new backlight I get 
> very low
> > > > voltage.
> > > > > > > >
> > > > > > > > Anyway, it looks like I need to get an inverter.  I can 
> get an
> > > > > > > > inverter from nightlaunch for $17.99+s/h but it needs 9V
> > DC.  I
> > > > > > > > understand the inverter in the K5 uses 5V DC.
> > > > > > > > 
> > > > > > > > Q1: Does the K5 inverter use 5V DC?
> > > > > > > > Q2: If I measure the voltage on the two wires to the 
> left
> > of the
> > > > > > > > inverter, should I get 120V if everything is working? 
> (My
> > > > Fluke says
> > > > > > > > it is good <=1kHz)
> > > > > > > > Q2: Does anyone know where to get a compatible K5 
> inverter
> > > and how
> > > > > > > > much it will cost?
> > > > > > > >
> > > > > > > > Thanks again for all the help.  This group is great.
> > > > > >
> > > > > >
> > > > > > Yahoo! Groups Sponsor
> > > > > > ADVERTISEMENT
> > > > > >
> > > >
> > >
> > 
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> > > =
> > > >
> > >
> > 
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> ://la=
> > > u=
> > > > nch.yahoo.com/artist/videos.asp?artistID=1001301>
> > > > 
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > >
> > --------------------------------------------------------------------
> ----
> > > > > > Yahoo! Groups Links
> > > > > >
> > > > > >     * To visit your group on the web, go to:
> > > > > >       http://groups.yahoo.com/group/k5synth/
> > > > > >        
> > > > > >     * To unsubscribe from this group, send an email to:
> > > > > >       k5synth-unsubscribe@...
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> > > > > >
> > > > > >
> > > > > 
> > > > > -- 
> > > > > antdes45 <at> n...

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nelsonj_sce | 9 Oct 08:41 2004
Picon

Anyone have sounds for the K5 Pro Editor


Has anyone converted the Kawai K5 sounds (the 9 cards) to K5 Pro
Editor format?  This seems to be the only editor I am having luck with
transfering sounds to-from my K5?  If you have them, could you please
post them under the K5 Pro Editor section (or PM me!)  Thank you. 

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kjtkfuenf | 9 Oct 10:21 2004

Re: How to fix a noisy ground?


Hi Jeffrey,

--- In k5synth@..., "nelsonj_sce" <nelsonj_sce <at> y...> wrote:
> 
> I am a bit disappointed that the
> Kfuenf editor still does not work for me.  

If you send an email directly to me, describing your problems, maybe i
can send a debug version to you to get more information about the
problems.

The complete rewrite of the rcv/xmt section of the Librarian is
ongoing  with Java JDK1.5 and the next version will have a better
control section with setting parameters for users with timing problems.

Klaus

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Antoine Deschênes | 9 Oct 16:43 2004
Picon

Re: Re: How to fix a noisy ground?

My MQX-32M(MusicQuest) shows up as a ð{Ð¥=§±ˆor something like this in the kfuenf editor, while the SBLive S/W synth and joystick ports are OK(The A and B SB synth are also strange characters).

developer-dyZUUg6L9wsdnm+yROfE0A@public.gmane.org a écrit:

Hi Jeffrey,

--- In k5synth-hHKSG33TihhbjbujkaE4pw@public.gmane.org, "nelsonj_sce" <nelsonj_sce <at> y...> wrote:
>
> I am a bit disappointed that the
> Kfuenf editor still does not work for me. 

If you send an email directly to me, describing your problems, maybe i
can send a debug version to you to get more information about the
problems.

The complete rewrite of the rcv/xmt section of the Librarian is
ongoing  with Java JDK1.5 and the next version will have a better
control section with setting parameters for users with timing problems.

Klaus





--
Signature
Antoine Deschênes /aka
  -´¯`-¸-DragonMaster-¸-´¯`-
http://thehotcom.deep-ice.com/
Files: http://www.angelfire.com/ca7/hotcomcenter/

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Antoine Deschênes | 9 Oct 16:45 2004
Picon

Re: Anyone have sounds for the K5 Pro Editor

And Overtone, SoundDiver, MIDI player have you tried them?


nelsonj_sce-/E1597aS9LQAvxtiuMwx3w@public.gmane.org a écrit:

Has anyone converted the Kawai K5 sounds (the 9 cards) to K5 Pro
Editor format?  This seems to be the only editor I am having luck with
transfering sounds to-from my K5?  If you have them, could you please
post them under the K5 Pro Editor section (or PM me!)  Thank you.





--
Signature
Antoine Deschênes /aka
  -´¯`-¸-DragonMaster-¸-´¯`-
http://thehotcom.deep-ice.com/
Files: http://www.angelfire.com/ca7/hotcomcenter/

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