Lectric FX Star Chambre delay volume drop

[Elvis Cocho]

Hello. I'm hoping to get a little bit of help from some of you smart folks. I built a Star Chamber Analog delay which is a clone of the MXR M-118 Analog Delay using the PCB from LectricFX. My build was successful - repeats sound great and it sounds like a great analog delay.

The only thing that's bothering me with this build is that the dry signal is suffering a volume drop going through this pedal. Could someone have a look at the schematic and tell me what part of the circuit I should be looking at to maybe change a resistor or capacitor value or try some other mod to the circuit so I get all my dry signal volume through? Thank you so much in advance.

[ElectricDruid]

It does a passive mix between the output of the input buffer (the dry signal) and the output from the delay (the wet signal) so I'd guess that's where the volume drop is coming from.

You could increase the value of R20 to boost the overall output, but that'll affect the echoes as well as the dry signal. With the mix fully over towards the Dry side, there shouldn't be any decrease in volume, I don't think. If there is a significant drop, I'd suspect a minor build error or a bit of short somewhere or something, rather than a design problem.

HTH

[Elvis Cocho]

Fantastic. Now I have something to roll with, thank you. If changing the value of that resistor boosts the overall volume of both echo and dry, that's perfectly fine. TM3 changes the level of the wet signal so I can balance it out with that control after I swap resistor values

[Elvis Cocho]

With the mix fully over towards the Dry side, there shouldn't be any decrease in volume, I don't think. If there is a significant drop, I'd suspect a minor build error or a bit of short somewhere or something, rather than a design problem.

HTH

With regards to this, I would compare the volume drop to using a vintage electro harmonix pedal where you're not losing something like half your volume, but still a noticeable drop.

It's absolutely possible to have made a mistake somewhere during the build, but I was very conscious of my process all the way through and I'm pretty sure I didn't do something like use a wrong value resistor somewhere or leave a solder bridge somewhere.

[Elvis Cocho]

Electric Druid, thank you for the advice. I increased the value of R20 from 100k to 150k. My dry signal is just a tiny smidge lower than the bypassed signal now and I think it's pretty acceptable. I think any perceived volume drop now is more because of the frequency response of the pedal rather than attenuation across my entire signal.

I could go to 180k but I think it's good as it is; I don't want to end up with an overall volume boost. Thank you again!

[ElectricDruid]

Glad you got it sorted