R1 value in Reverberation Machine + how to kill the dry signal?

[Addy Bart]

I think you're right actually, Gilbert. Looking forward to seeing if we can get closer to the gain in that YouTube clip (just as soon as one of us gets a spare moment!)

[KT]

Yes I also think that you need to make the 68k higher. Also check if your pot is wired correctly, if you change the lugs you get a different gain sweep probably.

This is an awesome circuit to mod by the way. Adding reverb pregain is easily done by adding a similar gain control to the opamp before the reverb.. Also adding clipping diodes gives you different kinds of drive.

[traktop]

KT wrote

Yes I also think that you need to make the 68k higher. Also check if your pot is wired correctly, if you change the lugs you get a different gain sweep probably.

The altitude knobs are correctly wired. I always thought that a linear pot would work better in this scenario though.
I was going to say that maybe a higher value pot would work better here, but being a 1M, making that 68k resistor higher is the only thing we can try here.

[Addy Bart]

Small Bear used to do B2M pots but looks like they've sold out. Maybe there's a seller on eBay...

[Addy Bart]

I finally tried a 2M linear pot for the gain and I'm getting that fuzzy goodness :-) If you can't find pots for that value, try increasing the 68k resistor.

[BassVD]

Aah, so it works! Thanks for confirming this one!

I've boxed up mine already, and am currently busy with some other builds, but it's good to know that it works anyway. :)

A friend was interested in buying my reverberation machine, but I offered to build one for him. And I'm probably (if he wants me to) going to put 2 extra pots on the enclosure: one for the gain of the dark circuit and one for the brightness of the other.

[Addy Bart]

I tinkered around with the dry path a bit more... Try socketing the 22k resistor. I found using 100k worked well. With my gain pot (2M linear) fully clockwise I get a nice fuzz.

[Addy Bart]

Actually, forget changing the gain pot and the 68k resistor that follows. The 1M pot works fine. After playing around with the 22k resistor, I settled on 47k - it gives me a nice fuzz but with the blend fully CW it still becomes very wet.