EA Trem build Questions/Problems

Started by Hiwatt25, March 05, 2007, 06:21:07 AM

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Hiwatt25

Finished boxing up my EA Trem and I like it a whole lot (tremolo is my favorite effect by far) but I have a couple questions that maybe you guys could answer for me.

First, the rate pot doesn't seems to influence the rate much until the last 1/4 of it's turn.  Then it goes from quick to real fast.  Is there a way to get more change earlier?

Second, and this isn't a problem so much as a question.  I wired the switch so that the power is cut (and the blinking LED turns off) when bypassed.  What I found was that when I engage the effect there is a moment of silence before it starts tremoloing.  Not really a problem like I said but I'm curious why that happens.  Do the capacitors need to charge up or something?  I think I'll just wire it back the way it was (LED always on) but probably will just build another one because that seems easier than moving two wires inside this one  ;D

Hiwatt25


markm

Hiwatt,
You may have another issue there somewhere as I wired mine the same as yours with the pulsing LED doubling as the power on indicator  but have not encountered the delayed start of the trem.  ???

Hiwatt25

Any ideas about where to start with a problem like that?  Sure would be great to have the LED serve as a rate indicator AND a function indicator.  Really, it doesn't bother me too much but would be fun to debug.  I wouldn't know what to look at first though.  Hmmm.  Could it be the switch?


Processaurus

Hi, for the rate pot, you want a reverse log pot, 100K works well,  that you make with a linear pot and tapering resistor, say a 500K pot and a 120K resistor (or 1M with a 110K resistor) from the wiper to one of the outside lugs.  The same outer lug you connect to the circuit (so the other outer lug is left unconnected to anything).  I learned that from the Geofex "secret like of pots".  You can buy the reverse log (antilog, reverse audio) pots too, at small bear and other places.

The LED thing is because when you have the pedal off, your wiring has done something that makes the LFO latch up, and it starts slow and makes a big transient that goes through the coupling cap to the gate of FET that puts it in a non conducting state while the DC level adjusts back down to 0v.

Try rewiring your stompswitch to short across the LED anode and cathode when you're bypassed, that way the LFO is going all the time.  Or you could even use a bi color LED, and just switch the power between the anodes from the green to the red, if you like blinky stuff all the time.