Discussion about the Korg PolySix synthesizer

I tested this by setting VR1,2,3 to their midpoint, inserted a trimpot for R93 and adjusted the pot for best scaling. It seemed to be about 40 point something K. 39K was the closest I had, so that's what I used. If you have more resistor choices (41K, 42K?) you might want to try one of those and see if you get better results, or even leave in a 50K trimmer.
Don B.

--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
>
> Hi,
> 
> Just wanted to say that I have been getting on very well with the  
> Silonex / 39k resistor mod. The only problem is the tuning is a bit  
> critical towards the lower end of the keyboard. Apart from that all is  
> well and I am on my fourth successful repair.
> 
> Cheers,
> Andy
> 
> 
> 
> On 23 Jul 2010, at 16:31, "longenough2002" <backshall1@...>  
> wrote:
> 
> > > Shucks, just noticed a note in the "files" section from gil_we  
> > back in Oct 2007 where he replaced the p1501 with a VTL5C3. I wonder  
> > if the lower temperature coefficient of the VTL5C3 makes it a better  
> > choice than the VTL5C2 for the tuning circuit? Some day, I gotta  
> > read the rest of the stuff in there.
> > Don B.
> >
> > --- In PolySix@yahoogroups.com, M Ll <f115@> wrote:
> > >
> > > Thanks for the update!
> >
> > > ________________________________
> > > From: longenough2002 <backshall1@>
> > > To: PolySix@yahoogroups.com
> > > Sent: Sat, June 12, 2010 8:53:50 AM
> > > Subject: [PolySix] Re: Replacement for HTV P1501 photocoupler?
> > >
> > >
> > > Got another Polysix in the shop with tuning problems. Same sort of  
> > thing with octaves "stretched" and it couldn't be corrected with the  
> > trim pots. The diode side of the photocoupler tested bad, so it was  
> > time to go shopping again. This time, I thought I would try one of  
> > the Vactrol parts, so I got a Vactec VTL5C2 from Small Bear (same  
> > place I got the Silonex part). I replaced R93 with 22K (up from  
> > 4.7K) and it seems to be working very well, so now we have a couple  
> > of choices for replacing the P1501.
> > >
> > > Don B.
> > >
> > >
> >
> > 
> 
> 
> [Non-text portions of this message have been removed]
>