Discussion about the Korg PolySix synthesizer

--- In PolySix@yahoogroups.com, Johannes Hausensteiner <johau@...> wrote:
>
> Hi,
> 
> IC34 SSM2056 is NOT the VCA but the EG. The VCA is built discretely
> by transisotrs Q5, Q6, and buffer amp IC33. Nevertheless IC34, acting
> as EG, could be the reason for different levels between voices,
> although I dont think that this is rather likely when it works
> otherwise. The VCA adjustment may correct or compensate the problem
> and it is not necessary to do it with an oscilloscope. If you just
> want to set the same level on all voices you can do this with a DVM
> in AC setting, provided the DVM has low voltage setting in AC; many
> cheapos do only have mains voltage range, though. You can measure at
> the headphone output; it has the highest voltage level (several Volts).
> OR: use your ears!
> 
> Good luck!
> 
> Johannes
> 
> 
> Andrew Jury wrote:
> > Hi TR,
> > 
> > As suggested by CJP you might have a problem with the VCA circuit. 
> > The VCA heart is an SSM2056 chip which is at position IC34 on the 
> > voice board (KLM-366) on the right-hand side with the top panel up. 
> > As an initial check you could try switching the VCA chips from one 
> > voice to another as they are socketed and can be removed without 
> > soldering. There are six in total, one for each voice. If you swap 
> > one and the problem shifts from one voice to another then this might 
> > be the issue. However, if you own an osciloscope (or know someone who 
> > does) I would suggest you check the VCA adjustment in the service 
> > manual (let me know if you can't find a copy). This involves 
> > adjustment of pot VR9 and comparing output waveforms. If you find you 
> > need to replace IC34 I have seen them for sale on eBay or you could 
> > try my old friend Senso at vintageplanet.nl
> > 
> > Also, the SSM series chips are CMOS based and sensitive to static 
> > electricity. Make sure you take the precautions to earth yourself 
> > before handling the internals. Drop us a line if you need any more 
> > help...
> > 
> > Cheers,
> > Andy
> > 
> > --- In PolySix@yahoogroups.com, "toerag_man" <toerag_man@> wrote:
> >> Hi, 
> >>
> >> Every sixth note I play is louder than the rest. Is this a common
> >> problem? Easy to fix?
> >>
> >> Thanks,
> >> TR
> >>
> > 
> > 
> > 
> > ------------------------------------
> > 
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6Yahoo!
Groups Links
> > 
> > 
> >
>
Thanks a lot guys. I really appreciate your time and knowledge on this.

TR