RE: Notes on Schems...

That's it, AG is analog ground, DG digital ground, +A6V dc analog 6v. . .
The kind of fork for the analog ground is an other sign for ground, maybe they mean different connection places, as the fork like is used for antenna too. But I think it's just a country/continent difference.

"nelsonj_sce" <nelsonj_sce-/[email protected]> wrote:

>
>Antdes,
>I just wanted to compare some notes on the schems.  I have not had a
>chance to dig too deep yet but I want to see if you reached some of
>the same conclusions I have on some of the notation...
>1) Many connectors have both "AG" and "DG".  Based on my quick look
>this seems to mean Analog Ground (AG) and Digital Ground (DG).  Do you
>agree?  In general something like "+A6" means "analog 6 Volts"
>
>2) It looks like the schems have a slightly different symbol for the
>AG and DG.  The AG ground looks like a horizontal line with three
>vertical swipes under it where as the DG has a more traditional symbol
>for ground.  Do you agree?
>
>The first thing I want to try is to directly connect all of the AG and
>DG cables to a single ground at the same place.  By any chance, have
>you tried that yet?
>
>Anyway, I think I have decoded the schems but I never hurts to compare
>notes. Thanks.
>
>
>--- In [email protected], Antoine Deschênes <antdes45@n...> wrote:
>> Mine's not at -65 but at -47 dB with the TL072.
>>
>> nelsonj_sce@y... a écrit:
>>
>> >
>> > 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 [email protected], "antdes45dragonmaster" <antdes45@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 [email protected], "nelsonj_sce" <nelsonj_sce@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 [email protected], "antdes45dragonmaster"
>> > > <antdes45@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 [email protected], "nelsonj_sce" <nelsonj_sce@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 [email protected], Antoine Deschênes
>> > > <antdes45@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@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 @ 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 [email protected], "nelsonj_sce"
>> > > <nelsonj_sce@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 @ 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 @
>> > > 380
>> > > > Hz.  I
>> > > > > > > > > think the inverter I ordered will put out about 95V
>@ 540
>> > > Hz and
>> > > > > > > > > should work with a 3 - 6 V DC input.
>> > > > > > > > >
>> > > > > > > > > Next step, 147k resistors (also ordered from Digikey
>> > > today).
>> > > > > > > > >
>> > > > > > > > >
>> > > > > > > > >
>> > > > > > > > > --- In [email protected], "nelsonj_sce"
>> > > <nelsonj_sce@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 @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.
>> > > > > > > >
>> > > > > > > >
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>> Antoine Deschênes /aka
>>   -´¯`-¸-DragonMaster-¸-´¯`-
>> http://thehotcom.deep-ice.com/
>> Files: http://www.angelfire.com/ca7/hotcomcenter/
>
>
>
>


-- 
Antoine Deschênes
aka DragonMaster
http://thehotcom.deep-ice.com/
Files:http://angelfire.com/ca7/hotcomcenter/


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