Want more depth from your EA Tremolo easy?

[Processaurus]

Found an easy way to give the EA a little more cajones.  Just put another FET in parallel with the one thats there acting as a variable resistor (Q2 on the run off groove schematic: (http://runoffgroove.com/eatremolo.html)

Just solder each corrosponding leg together, like hook the gate to the old FET's gate, source to source, and drain to drain.  

Since the FET acts as a variable resistor, and two identical resistors in parallel amount to half the resistance of each, the idea was 2 fets in parallel would have a lower resistance when on, making the main transistor amplify more on the tremolo peaks.  This makes for a louder output on the peaks, so you turn the volume down, the valleys are quieter, ie: more depth.  

The overall circuit gain is doublish now, which may possibly cause the circuit to clip, depending on how hot the guitar signal is.  There's no clipping with when I tested it with a strat, but I'd be interested and grateful if anyone knows how to lower the gain, besides attenuating the input (BTW I made the GGG "improved" version, with the JFET input buffer and the 2n3904 doing the tremolo, rather than the ROG Mosfet version).  

Anyway, this is a good tweak, for tweakers.  One could maybe even put 3 or 4 fets in parallel for super deep trem, if you had a way to lower the overall gain.

Another thought on this effect is the rate pot being reverse log 100k makes a much nicer sweep than a linear pot, where its nothing, nothing, and then woah, all of a sudden all the action is in one small area of the pot.

[sean k]

One way is to use negative feedback either a resistor from the collector to the base,biggish(something I made had two 220k's in series with a .001n cap to ground on the junction which would effectively lower the gain with negative feedback but leave a small treble boost),or,I made one of these a few days ago,but can't remember if it has a cap on the emitter resistor...duh,of course it has...for the trem so that won't work.Maybe a voltage divider somewhere before the 2N3094.

[onboard]

Cool!  The EA Trem. It's not your Father's tremolo.


Seriously though, parallel jfets - would that be the same as choosing a jfet with 1/2 the Vgs that you were using,  or am I not getting that?

[Paul Perry (Frostwave)]

Cool!  The EA Trem. It's not your Father's tremolo.

It probably IS your father's trem, if you look at the date on the original article
Putting fets in parallel?? anything could happen, seeing how wide a range the characteristics vary over.

[Ge_Whiz]

I used a 2N5457 in mine, and it already goes full-depth at the top end of the depth control. FET variation, again.