A month or so ago, I built the BYOC Brown Face Harmonic Tremolo. The kit went together fairly easily and I got it up and running in short order (there are two trimpots to set and then balance the output level through the range of the Depth control). I plugged in and hit the obligatory E7 chord, and OK - there’s a tremolo effect going on, and it’s kind of vibe-y/phase-y, but where’d my low end go??? I’ve never heard a real Brown Face tremolo, so maybe it’s supposed to sound like that? I didn’t have time to mess with it before leaving on our spring break vacation, but I did use some idle time to do some research (and try to avoid the news - this was the 2nd week of March). In the BYOC design, the low pass filter is formed by a 220K resistor and .01uF capacitor, giving a cutoff frequency of 72 Hz; the high pass is implemented with a 250pF cap and 1M resistor resulting in a cutoff at 637 Hz. Even at only a 6 dB per octave slope, that’s going to scoop a lot of bass and low mids. I found a schematic claiming to be from a 1960 Showman - it has the same HPF but the LPF uses a 5nF cap, so the cutoff is 144 Hz. So the scoop wouldn’t be as pronounced. Back home, and now with a lot of time on my hands, I started looking at how to mod this thing. I clipped a 250K pot in parallel with the 220K LPF resistor and turned it until it sounded thicker without being muddy. I measured 110K on the pot, giving me 165K total resistance and cutoff around 96 Hz. I wanted to keep the stock tone and use a switch to provide the alternative LPF cutoff. The only toggle switch I had was a DPDT mini from an abandoned project, and I had a 100K 1/2W resistor due to an ordering mistake (I have a lot of 1/2W resistors from that same mistake). So I forged ahead with more switch and more resistor than I needed. Another challenge was that I would have to unsolder the 9V connector leads in order to completely remove the PCB from the enclosure. Even if I did that, my oversized switch and resistor wasn’t going to fit topside where you expect a switch or knob to be. I could have put it on either side of the footswitch, but opted for the bottom end because, with the PCB still installed, I could see and better control the metal shavings when I drilled the hole. Not really an optimal location for a user, but hey sometimes we gotta make do. Pics, audio and FR plots here. (I’ve built 8 or 10 pedals from kits - this is the first time I splurged on a painted enclosure. I guess I dig brown) If you’ve made it made it this far… I’m taking suggestions for what to label my switch. The idea that’s stuck in my head is a boring “LPF 1-2” (or maybe “1 LPF 2” on the physical label). Gimme some fun suggestions, like a plausible misnomer (out of respect for the heritage of guitar effects) or something boutique-y. And thanks for reading my post!