Small Stone Siren

[Primus]

I have been trying to get my commercial Small Stone to work at unity gain. There are a number of forum posts dealing with this problem for the Tone Pad version. I started by locating the resistor connecting the input transistors (Tone Pad R42, EH R6) and replaced it with a 10K. Plugging the phaser back in with the color switch on normal mode gives unity gain but maybe a little less subtle effect. Switching the color switch gives insane siren feedback. I have been trying to locate the resistor divider network on my commercial unit, which is different than the Tone Pad layout to locate the equivalent part but I have had no success yet. Can someone who has worked on the commercial unit help me track this problem down?

[EDITED WITH MORE INFO]

Okay, Here is the tonepad schematic: http://www.tonepad.com/getFile.asp?id=7
And the J series Small Stone: http://www.montagar.com/~patj/smlstone.gif

What I did was take the 4k7 resistor that is R42 as per the Tone Pad layout or R6 on my PCB or the resistor between the two input trannys on the linked schematic and raise it to a 10k. This fixed the volume drop perfectly, but introduced way too much feedback into the color section. It is reported that I need to track down the 3k3 resistor that is R11 per the Tone Pad layout and raise it to about 100k. In the small stone circuit it looks like it is part of the path connecting the on position of the switch to pin 6 of U4. I can't seem to find this resistor on my reissue Small Stone, however...

[Primus]

This guy is about to fall off the page, but I wanted forum lurkers to see the new info that I added.

[adam_f]

Hi,
just thought I'd mention I had this exact problem last night with my small stone - built from the tonepad layout, and with R11 changed for a 10k and R42 changed to a 10k (as in the mods on generalguitargadgets).

Anyways, I saw your post so and tried a 100k in R11 and suddenly it worked perfectly. nice subtle phaser when color switch down, and more promient swooshing wah like phaser when up. Beautiful, I love it! Cheers,

Adam