Your Source for DIY Pedal PCBs and NostalgiTone! › GuitarPCB Forum › GuitarPCB Build Support › EA Tremolo Speed control
- This topic has 6 replies, 2 voices, and was last updated 11 months ago by
Ben.
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February 9, 2025 at 3:19 am #35355
Ben
ParticipantHi, I’ve just finished building the EA Tremolo from a kit. The pedal is working as expected, but the Speed pot appears to be working backwards- ie fully counter clockwise is fastest, and fully clockwise is slowest. The pot supplied is a C100k. Most of the change in speed happens in the first 1/4 of the pot turn (between minimum and 9 o’clock). Is this the expected behaviour for that circuit, is the pot the wrong value/type, or should the pot be oriented in the other direction (meaning that the drilling guide is wrong)?
At the moment, I’m planning to rewire it with flying leads so I can try it the other way around.
Thanks!
Ben
February 9, 2025 at 12:35 pm #35357
BarryKeymasterAs for the value of the pot it is exactly the same value as the original circuit. That said you can try an A100K to see if you like the feel of the taper better.
The C Taper is based on JD Sleeps or runoffgrooves modification from many years ago:


You can reverse lugs 1 and 3 of the Speed control by hand wiring them as you mentioned.
February 9, 2025 at 2:11 pm #35358Ben
ParticipantThank you. I suspect that reversing the pot will fix the taper issue. I guess I was more just wondering if the control is supposed to work backwards like that using the v4 build guide or if that’s a mistake.
February 9, 2025 at 4:45 pm #35360
BarryKeymasterYes, that is how this particular circuit is. What will affect the Taper “feel” is changing the pot from a C Taper to an A Taper however many people prefer the C Taper. It is all subjective.
February 10, 2025 at 2:00 am #35363Ben
ParticipantOk thank you. Reversing the 1 and 3 pins on the pot using flying leads has made it behave as I would have expected (fully clockwise = max speed), and the taper feels more even. Great sounding trem and boost! Makes me want to fine tune it to go a bit faster and deeper at the extremes- which component(s) affect the maximum speed and depth?
February 10, 2025 at 12:06 pm #35365
BarryKeymasterYou can take the three capacitors C6, C7, and C8 and reduce them all to 0.68uf for a faster available rate.

The EA Tremolo circuit is quite simple and known for being a smooth Tremolo. If you really want a modern design that goes to extremes, and do it well, I highly suggest the Apollo Tremolo.
February 12, 2025 at 7:41 pm #35380Ben
ParticipantExcellent. Thank you very much
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