Re: Notes on Schems...update on grounding experiment

Also, I get some -47 when the volume isn't even at max. So I'll give a
try to these OPA4228, and the 2 chan version in some preamps and DACs.

--- In [email protected], antdes45@n... wrote:
> My mixer plugged to the line in gives me -55 and my K5 plugged to
the line in gives me -55 too. I did the 147k hack but with 150k ones,
I got a problem: the last 1/12 boosts the volume x3, and when I switch
up and down from the 11/12 to the 12/12 part, I hear a pop between
them(BTW it doesn't distort, except for crappy low W headphones.
> 
> "nelsonj_sce" <nelsonj_sce@y...> wrote:
> 
> >
> >OK - I am note sure this is an apples-to-apples test but here is what
> >I did.  I have a Yamaha DSP2416 mixer in my computer.  I hooked up my
> >K5 to the mixer and then read the levels from the mixer.
> >
> >I did all tests while my K5 was in multi mode, I tested both the "mix"
> >output and the "1" output and turned the mixer channel on my computer
> >all the way up.  I did not hit any notes, so I was just looking at the
> >noise level, and I did not run through any FX or noise gates, I just
> >ran the K5 direct to the mixer.
> >
> >Results:
> >
> >1) With the K5 volume at minimum I was below -72dB on both "mix" and
> >"1" outputs.  This was the same reading as when the K5 was not even
> >plugged in, so there was no additional noise.
> >
> >2)With the K5 volume at MAX, the "Mix" output was just above -66dB and
> >the "1" output was just above -72dB.  NOTE: I did the 147k resistor
> >hack, so my MAX output is much hotter than a stock K5.
> >
> >I am not sure how my K5 would do if I used the same setup you used,
> >but this was the best I could do with the equipment I have.  I hope
> >this helps.
> >
> >
> >
> >
> >
> >
> >--- In [email protected], Antoine Deschênes <antdes45@n...>
wrote:
> >> Could you do a little VU meter test, with mix output if you have
> >changed
> >> the opamp for it(The same opamp is for headphones) or single if not,
> >> without a noise gate or anything else at minimum volume? I'd like to
> >> know how many dBs is it now.(I sat my SBLive VOL adj. at -90dB on
> >the VU
> >> meter(Software) without anything plugged in the Live, then
plugged the
> >> K5 in the Line In and i got a -47dB.
> >>
> >> nelsonj_sce@y... a écrit:
> >>
> >> >
> >> > Hack update:
> >> > Since my last note I replaced the other two op-amps with
socketed Burr
> >> > Brown OPA4228.  Replacing these two other op-amps did reduce noise
> >> > levels noticeably.  There is still some noise but with 1)the these
> >> > four super clean op-amps, 2)using Multi, 3)routing everything to a
> >> > sinlge output on the multi rather than mix, and 4)using my
noise gate,
> >> > noise is really not an issue any more.  I would love to try and
> >> > replace the VCAs also, but I have not been able to track down a
spec
> >> > sheet (or any other info on the) on them so I do not have a clue as
> >> > what might works as an upgraded part.
> >> >
> >> > If anyone can help, the VCAs are part M5222L and they are from
> >> > the same off-brand Japanese JRC company that is used elsewhere
in the
> >> > K5.  If anyone can help me with details on the M5222Ls I will
see if I
> >> > can find a replacement parts.
> >> >
> >> > My bottom line: If you are willing to lay-out $30 for the four BB
> >> > OPA4228 and sockets, and you if you are willing to remove some
> >> > tough-to-remove parts, I highly recommend this op-amp replacement
> >> > hack.  My K5 has much less noise and just sounds much
warmer/classier
> >> > with the new parts.  I would love remove more noise, but right
now it
> >> > sounds very good and I am not very motivate to continue
hacking.  (I
> >> > do still plan on replacing the headphone circuit though since I
> >> > already made the new circuit and all I have to do is wire it up.)
> >> >
> >> > An interesting aside:  After I did the latest op-amp replacement,
> >> > everything sounded great in multi, but when I went to single I had
> >> > serious problems.  Various ranges of the keyboard worked fine,
while
> >> > other ranges sounds like a fried amp circuit.  It turns out
that while
> >> > I was removing IC8 I accidentally pulled part of the circuit board
> >> > trace off that connected pins 1 and 2 on IC8.  This trace
provides the
> >> > feedback loop between the (-) and output of line G2.  Once I
tracked
> >> > down the problem I was able to reconnect pins 1 and 2 and then
> >> > everything in single mode worked great.  What I conclude from
this is
> >> > that the K5 in single mode is splitting different ranges of the
> >> > keyboard to different op-amps.  I am not sure what K% is doing in
> >> > multi but multi (ouput 1) DOES NOT use the opamp in IC8 pins 1-2-3.
> >> >
> >> > Hack on.
> >> >
> >>
> >>
> >> --
> >> antdes45@n...
> >
> >
> >
> >
> 
> 
> -- 
> Antoine Deschênes
> aka DragonMaster
> http://thehotcom.deep-ice.com/
> Files:http://angelfire.com/ca7/hotcomcenter/
> 
> 
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