EHX Small Stone V1 Volume Drop

[Grrrg]

I recently got my hands on a Small Stone V1. I really like the sound, but as is known all about the internet, there is a considerable volume drop. So far I found out, that people were changing the feedback resistor on the input stage (marked R1 in attached schematic) I replaced it, by putting in a pot and turn it up until it started feedbacking while the color mode was engaged. I measured 3.5 kOhm and put in a resistor. Now the volume drop in color off is not so bad anymore, but in color on it still is pretty big.
What do you think could be done to make it less? I was thinking if I put in smaller resistors for both the two mixing resistors (marked R2 and R3 in the schematic) would that help without changing to much? But then in color off it would probably be louder than the bypass signal.
Or (as I understand it) the Input signal when color is on is going through R4 which is 100kOhm. Would it help to put a smaller resistor in place of R4 to fix the volume drop in color mode?
What do you think?


Thanks in advance

[Mark Hammer]

I think the best approach is to think like EHX. At the time the Small Stone was released, everybody used SPDT stompswitches. Because of that, the circuit input was always connected to the input jack, and all the stompswitch did was disconnect the output of the circuit board, and substitute it with a connection to the input jack. Because the circuit's input loaded down the signal (especially if there was more than one pedal in the signal chain), the effect had to offset that by providing a comparable signal level in "bypass". After all, you wouldn't want the effect to always be louder than the bypass. Indeed, one of the regular complaints from folks who insist on installing "true bypass" 3PDT switches in their old EHX pedals IS the discrepancy in volume between effect and bypass modes when the circuit is bypassed entirely.

So, the "solution" would seem to be offsetting the volume reduction that the circuit imposed, in order to achieve the balance. I'm going to guess here that reducing the values of bothR2 and R3 would help in that respect. Since they need to be the same value, in order to achieve a 50/50 balance of dry and wet for maximum phasing effect, I'll suggest making them both 18k, as a starting point.

[Grrrg]

Thank you, Mark.
That seems to me like I should put in a true bypass switch first before playing around with the volume drop.