K5synth

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 k5synth@yahoogroups.com, 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...