Another interesting circuit from Spaceman, traced by Dino T.. The vero is verified and I decided to include Dino's mods. The Depth Switch is a internal DIP switch in the original pedal, here it's external. Also the trimpot replaced the 16k resistor found in the original. This allows you to try different types of vactrols or LED/LDR combos.
It's quite picky about transistor selection, Q1 and Q2 needs to be matched, otherwise it will gate and the fuzz will sound ugly. BC179C and BC109C with hfe 573 and 571 worked best for me here. The original had a P416A for Q3 which is a low gain and low leakage russian PNP germanium. Many low gainers sounded good here but a settled with a MP40 (Hfe 52).
I just recently built a Pong War Machine .. this kind of reminds me of it from the videos I watched. Except the WOW has a more palatable fuzz, and there doesn't seem to be any LFO tick present on the WOW! Also I am now seeing that these ferrite beads are present in basically all Spaceman builds. So yeah props to you and Dino sir, I appreciate these layouts. How about the Voyager? ;)
Has anyone that's built this "Rolled Their Own" vactrol? I was looking at the specs on the 5C3, and I'm fairly certain a 5549 LDR and a diffused LED might work, but I was hoping someone had already gotten it going with their own rolley, let me know if so, otherwise I'll just have to experiment. Thanks again!
What gains on your 2N5087/8 ? How closely do they need to be matched ? I built it with a 431 NPN and a 420 PNP, it seems to gate once the gain knob is turned down much. Also once I dial the trim pot in for the vactrol it sounds pretty decent with the gain up, but if I flip the depth switch I'll have to dial it in again .. I'm thinking something is wrong. I have the VT5C3 workalike from small bear, a 5537 with a diffused green and a 5539 with a diffused red, and they all work with some trim pot tweaking. Anyway, just curious if anyone had similar results.
If I wanted to increase the maximum speed .. would I need to mess with the 430k and 62k there with the 150n cap? I finally got this working and sounding bomb, but the speed range is kind of ho-hum in my opinion. Slowish rate with depth double and gnarly chop is pretty fun
I used a 5539 and a diffused green led, removed the 13k and put in a 3k and a 10k trimmer in series on a little strip 8x3 or so and adjusted it to Dino's spec on the gallery layout PMowdes linked.