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Any ideas for how to modify the Brown Face Tremolo (2nd version) so that the minimum rate can cause a slower modulation?

Thanks.

Replace C13/15/17 with larger value capacitors. These are the spaces marked 104 on the PCB, but have been changed to 154. Maybe try 224 (.22uF) or 334 (.33uF).

Unfortunately, when you do this, you will slow down the fastest rate as well, so it's a give and take. Ideally, you'd use a C150k pot, but these aren't commercially available. A larger pot would allow for slower speeds without reducing the max rate, but the next size up is 250k and this will cause the LFO to shut down and not start up again till you turn the power off and back on.

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*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

by C150k do you mean a reverse log 150k pot?

Thanks!

Yes, exactly.

Question for Keith: How about soldering a 390K resistor across the two outer lugs of a C250K pot? That would decrease the max. resistance to 152K.

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Yes, that would work, but I'm not sure how much of an effect it would have on the taper.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Might be an interesting thing to at least try. It's certainly easy to do....and undo!

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Has anyone tried this? I'd totally try it. I'm like maybe a 2 out of 10 on electronics and don't really know anything, but would it also be possible to use a 50k resistor in series with the stock 100k pot? Not that I'd know where to put it (or them). I'm ok with a slightly wonky taper.

I tried the C250k pot with the 390k resistor on it. It worked okay and did slow the rate down a bit, but not that much and if turned too low or high, cut the signal entirely or cut the effect and just passed a dry signal, respectively.

So I reverted it to the original. Waiting for some parts to come in and I’m going to try the capacitor replacement but with a switch so I can go between original and modded rates. I do really like how it sounds at the fastest rate so I don’t want to sacrifice that.

Ah, thanks for the info. That's a good idea with the capacitors. I wouldn't want to lose the fastest rate either, but I'd be fine being able to shift between high gear and low gear.

I'm not sure of the exact perfect value. Reduce the value of the 390k resistor till you get it to a point where it doesn't cut out on you at the slowest rate. I'm not sure how this would be affecting your max speed, but if it's cutting out on you at full turn clockwise, then increase the R28/1k8 resistor till the LFO stops cutting out.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I tried it too. I first replaced the 100k pot with a 250k pot, and with that value, it just stops, as everyone said it would. I then added the 390k resistor in parallel. With that in the mix, it had a more useful range of speeds, but I could still stop it, and as it approached stall speed, the effect would lessen, to the point where there was none, even at max depth. I didn't have any problems with it at the fast end of the range, and I also didn't have to reset it after stalling it out... it would start up again on its own (eventually) if I turned the speed way up, but it was pretty janky. I started going through other resistor values until I found the biggest one where it wouldn't stall out even at the slowest end of the range. That number for me was...........200k.

So, with that in parallel, I think it's a total of 111k.

It think it's pretty damn close out of box. Mine might be like 5% slower than stock now, if I'm counting the pulses right, but it's barely noticeable.

I still think it would be fun to experiment with changing the capacitors, and I like the idea of putting them on a switch, but I'd have to think through how to actually make that work (and where I'd fit the switch). I barely know anything about this stuff, but it's fun to mess with.

Putting those 3 LFO caps on a switch is the best way to go, but is probably the most complicated. You could use a 3PDT on-off toggle switch. (you really only need a 3PST toggle, but I don't think they make those, so you just wouldn't use the second half of the switch). Install your "fast" caps to the PCB. You want these caps to always be in circuit. You then use the switch to add the other caps in parallel with the hardwired caps to increase their overall capacitance.

I don't know exactly what the values would be for "fast" and "slow". If I had to guess, I'd use .22uF caps for "fast" and add 1uF caps for "slow" (which would give you a total of 1.22uF). Ideally what you want is something that doesn't leave a gap between the slowest "fast" speed and the fastest "slow" speed.

Extra credit: The Jen HF Modulator uses this exact same LFO circuit with .047uF caps. It's nothing more than a tremolo with a crazy fast speed. You could use a 3PDT on-off-on toggle switch and have "fast", "slow", and "ring mod" ranges.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

This totally worked.

I probably didn't do it in the most ideal way, and I added a lot of inches of wire to the circuit because the 3PDT switch was so big I couldn't fit it in many places, but it works.

I connected leads under the stock capacitors:


Tested that the 1uF caps worked:


And then wired the switch with the 1uF caps with a lot of heat shrink to try to keep all of the electricity in its lane:


It now has a low gear that will go very slowly. Below about 10:00 on the speed knob, the effect will be basically disappear, but I'm fine with that.

Here's a crappy sound sample with the entire range of the pedal:
https://sailingfortuitous.com/whatever/ ... owgear.mp3

0:00 off
0:06 high gear/highest speed, then progressively slower
0:47 switch to low gear/highest speed, then progressively slower

Thanks so much for your help! This has been super fun.