DEFX Q2 - resonator - self osc issue

[Furrball]

Hello,
I finished building my Q2, got it all adjusted per instructions, works well, and there shoudnt be any questions right? 

So I compared it to my original frostwave resonator and there is a huge difference in the way the original self oscillates. The original has a much wider frequency band, and much more fluid sound (were still talking self oscillation here). my clone is very rough sounding and steppy at times (still talking self oscillation). I wish I had sound files to show but i do not at this time. i tried to adjust the trimmers on my clone to get a bit more out of it by going a bit further than the instructions mentioned. But i still cannot get nowhere near it or sound the same, or even similar. The frequency trimmer is maxed out now on the LP side. Im guessing this is zero ohm side of the trimmer. I need the filter to open up more to get into the originals territory.

My original, you can crank up the reso and the freq to the point the sound goes so dang high, it disappears. moving the the freq very fast you can get a great 'zap' sound. my clone doesnt do much of this.

So before you question my build, ive double checked all the parts many times (even with a meter), some parts are in sockets so i can swap out things to test/modify. I used decent quality parts (possibly same as original) and ive built dozens of pedals and fixed many analog synths.
I did notice a few things last night though. My original resonator is a version 2.0. (not sure what the Q2 schematics are based from) I have  compared the schematics to my original and noticed a few differences. first off, my original uses 5485 jfets. I dont think that is a huge issue but a difference right?  So I did swap in a set of 5485 and no difference was made. Second, the freq trimmer on the original is 20k vs 100k. So I swapped that and no big difference was made either. I swapped all the chips I had socketed with spares and still the same (all the chips and transisitors). Still no difference...
But as I looked at my original a bit more, I noticed that all the electro caps (except for the power caps) are all 10uF, every one of them!
My question now is, do you think this could be the difference I am looking for?

Thank you for any help, I appreciate it, and thank you DEFX for bringing these old boards back to life.
chris.

[ElectricDruid]

Hi Chris,

Welcome!

You're talking about this one, right?

https://drive.google.com/file/d/148aqAqUOM5-XsuSauo0e-Mga_5cJ76qS/view

[Furrball]

Hello! Thank you!

Yes!
I have the version of theirs that uses the blue PCB board, it says Q2 v.2.

[Furrball]

Ok, after a while of tracing the whole dang circuit board on my original V2 resonator I found a few differences that made a significant change to my clone.

I found that my clone had the low freq for the self oscillation was weak and it was also not as loud as the high pass side.
Yeah, I know most people don't care about the self oscillation, but the cool thing with this pedal is the character it has by mixing the low pass and high pass in self oscillation (just as in the real MS20). You can get some very cool and very strange sound effects out of it.
My main concern was that since my clone couldn't perform like my original, there was something different.

After swapping parts and testing every trace, here are my results of the differences with my original verses the clone:
-All electro capacitors are 10uF 35V (except power section) - I used 10uF 50V cause that's all I have on hand right now.
-C23 on my original is 2.2N  - The DEFX schematic shows 22N. This change of capacitance evened out the sound and changed the freq/res on my low side to match my original unit.
-I matched transistors Q7/Q9 and also Q2/Q3. This probably doesn't matter much but I did it anyway.
-my original uses 2n5485 jfet but the 2n5484 works the same.
-I am using 1K and 20K trimmers as the original and getting good tuning out of them. I have no need for the 100k trimmers now.
-R11 on my original is 2K ohms. DEFX schematic shows 2.2K ohms.
-Different brands of red LED will slightly change the character of the filter, I tried different colors and sizes too but it all boils down to preference. It seems my clone likes the BIG red LED best. No LED for a smoother and much louder sound.
-In my original, almost all of the resistors for the CV control are all 1%, but the rest of the resistors in other circuits are 5% CF.

Im not saying these are errors, Im just saying my original resonator is a bit different than the clone and I dunno why. Maybe my original resonator is different because these are mess-ups when it was built, I dunno... but I love the way it sounds!

My original says its a board version-2 and has a blue chassis that has the four screws on the bottom. I believe this to be the last generation of the pedal. I owned two back in the day and the generation before it (my other old one), had it where the bottom flips open on a pivot. My version I have now, doesn't have the pivot style chassis.

These component differences may be due to whatever reasons we do not know, but I thought they were worth mentioning so that if others are building this unit (or repairing one), they can compare theirs to mine.

Furr