Discussion about the Korg PolySix synthesizer group photo

Yahoo Groups archive

Discussion about the Korg PolySix synthesizer

Index last updated: 2026-04-09 23:04 UTC

Message

Re: Replacement for HTV P1501 photocoupler?

2010-07-23 by longenough2002

> 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.
> 
>

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.