In my last entry I talked about my preference to keep a pedal circuit build as close to the circuit it's cloning as possible, and avoiding customizing it to my person desires. But what happens when a circuit doesn't turn out anywhere near what I expected, or even what anyone expected? Well, that's where the journey begins! As 2023 is a year of experimentation and broadening my horizons by building things that I wouldn't normally build, I attempted a simple tremolo circuit. Much like fuzz I'm not a big fan of tremolo, but I do love the sound of it on those 60s classics, so I figured if I could add one to my arsenal I may as well. The build layout was chosen, and after it was completed the resulting circuit turned out far too quiet to be of any use.
This seems to be a common issue for this circuit. I won't blame the layout because it could be based on a bad schematic, I don't know. The standard troubleshooting was done, going over it part by part to make sure everything was the right value in the right place and after a dozen or more times it seems I built it correctly, the layout just doesn't work as presented. I removed both power and all of the transistors and found the circuit still passes signal, that doesn't seem right, so I know something is wrong. Regardless, I went a step further and experimented with a few things to see if I could get it to at least become something I could actually use.
I started by fiddling around with the four required transistors, and swapped a few out for lower gain transistors. In doing so I found which one of them was pulling the signal down, and removing it helped with the overall volume loss, still not anywhere near unity, but it was better. With three of the four required transistors the circuit was working pretty well, but it still wasn't as loud as it needed to be. Then a plan formulated in my head. Many years ago I built an LPB-1 clone with a BMP tone stack, completely misunderstanding that the boost circuit was the recover stage for the tone stack, and not in fact an LPB-1 with a tone stack, so I always considered it a failure. I removed the BMP tone stack, tacked the LPB-1 circuitry onto the backend of the tremolo circuit and voila!
Now that the circuit was not only amplified, but actually can act as a bit of a boost, the effect felt a bit too thick. What I mean is even though the depth control works, there is no clean signal getting through. I know that's just how it's supposed to work, but when everything goes through the tremolo effect, it just feels too thick to me. I did a little bit of research and found a tiny blend circuit, which worked out perfectly. I can blend in clean with the tremolo effect and it actually sounds a bit like a poor man's uni-vibe with a 50/50 mix. It's still not perfect, but I feel this is now much more useable than it originally was.
Again, I won't blame the layouts or their creators, because maybe it was a bad schematic. I've noticed this issue being reported for a few different layouts of this tremolo circuit. I've gone over mine time and time again and it's exactly the same as the layout, so who knows. I'm leaving everything as is with the circuit, plus the tacked on boost and mix boards, just in case a solution comes up in the future and it's an easy fix. But really, with all the fun I've had building and experimenting to make this tremolo circuit work, I'm not sure I would want to take it apart to fix it later down the road. I'm not even sure how often, or if I'll ever use it much at all, but the destination of where this circuit is now, after all the experimentation, I can say I'm pretty happy with what it became.
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