Can the EA Tremolo have a "chop" function?

[Mark Hammer]

The origins of this request are pretty lame.  I have a 1590B that I drilled for 3 pots and a toggle in a manner that accommodates an EA Tremolo board (Paul Marossy's layout.  Thanks!), but nothing else I want to build right now.  So I'm trying to think of what I can do with that toggle hole.  I was wondering if there is anything simple one can do to alter the LFO waveform in a productive way that would let me put the toggle hole to use.

Can a "chop" (close to square) function be produced?  Alternatively, is there point to attempting to soften or round off the LFO more than it currently is?  Either of those would do it for me.

[MikeH]

If you disconnect lug 1 of the depth pot it gives you a bit of a more "choppy" feel, although nothing like that of a EH pulsar

[Paul Marossy]

Cool, glad my layout was useful to you Mark. 

[R.G.]

The simplest thing to do is to take the signal at C4/R7 (GGG schematic) and run it into another amplifier. A slick trick would be to use an opamp and set the gains up so that the mostly-sine-wave at C4 becomes a slope-sided square. A gain of 2-4 should do it. Bias the opamp dead middle of the power supply and AC couple to it. Switch between the C4 signal for the depth divider and the output of the new opamp, appropriately resistor divided to a comparable size as the C4 signal.

[Paul Perry (Frostwave)]

Maybe a diode or two in series with the source on the J201 would make the modulation more choppy?

[projectx102]

 I find that when I run mine into the FX loop( added by Mark Cameron) as opposed to in front of my Marshall 2204 the effect is much more prominent and choppy when you crank the depth.I love this pedal! it's great as a boost too.

[Mark Hammer]

The simplest thing to do is to take the signal at C4/R7 (GGG schematic) and run it into another amplifier. A slick trick would be to use an opamp and set the gains up so that the mostly-sine-wave at C4 becomes a slope-sided square. A gain of 2-4 should do it. Bias the opamp dead middle of the power supply and AC couple to it. Switch between the C4 signal for the depth divider and the output of the new opamp, appropriately resistor divided to a comparable size as the C4 signal.

I sort of figured that the tap point would be the C4/R7 junction, but the rest of it went way over my head.  Is the basic idea that some additional gain applied to the initial waveform, and constrained by the inherent voltage-swing limitations, would yield a sine-ish start and square-ish finish?

If so, then why not simply clip/clamp the LFO signal at C4/R7 with a suitable diode or two?  Or will that result in a square-ish top at an amplitude that cannot give the JFET gate what it needs?

[Mark Hammer]

Well, no chop function, but what I did do was install a "lazy" function.  Basically, it's a 100nf cap between ground and the junction of the depth pot and 560k resistor preceding it.  If you have built any of the various versions using a smaller value resistor than 560k, you'll need to adjust the value of the cap upwards.  The stock modulation is nothing I would call "chop" by any stretch, but the added cap provides a different feel that just seems less abrupt or urgent.  For the cost of a cap and a SPST toggle you have a bigger palette.

[cpm]

i am thinking of putting a tremulus lune LFO into the EA, i love the spacing pot in the Lune