Hi Don/ Andy and thanks for your advice and feedback, Maybe a dummy question but how does one replace the P1501 with a VTL5CX ? Btw. did anyone find out already if its better to use a VTL5C2 or VTL5C3 replacement? Thanks for the answer(s) in advance. Simon --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote: > > Thanks Don, > > You advice and expertise are much appreciated! I shall have a bit more of an > experiment, but I am at least ending up with the playable instrument for my > efforts rather than the sound of a piano that has been dropped out of a > window! > > Cheers, > Andy > > > On 27/07/2010 13:35, "longenough2002" <backshall1@...> wrote: > > > > > > > > > > > > > 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 <mailto:PolySix%40yahoogroups.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 <mailto:PolySix%40yahoogroups.com> , M Ll > >>> <f115@> wrote: > >>>> > > > > >>>> > > > Thanks for the update! > >>> > > > >>>> > > > ________________________________ > >>>> > > > From: longenough2002 <backshall1@> > >>>> > > > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.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] > >> > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] >
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Re: Replacement for HTV P1501 photocoupler?
2011-05-10 by ltern_te
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