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DIY Stompboxes => Building your own stompbox => Topic started by: u1061810 on May 21, 2004, 06:37:29 AM

Title: EA Trem ?
Post by: u1061810 on May 21, 2004, 06:37:29 AM
Hi All,
 I'm working on the  EA trem located at GGG,( The improved version)and it lists a 25k log pot for rate(speed) control, but I only have a 50k on hand.
 Can I just put a 50k resistor across the outer lugs in this situation, or is it not applicable here?
The wiring on the pot is:board to the third lug, jumps to the middle, and the first lug  to ground.Thanks for any help on this newbie question.
Title: EA Trem ?
Post by: gez on May 21, 2004, 08:43:45 AM
Here's another version of the EA:

http://www.runoffgroove.com/eatremolo.html
Title: 1
Post by: u1061810 on May 21, 2004, 09:28:01 AM
Thanks for the reply, but I've got the G.G.G. board,and me being such a novice, I thought I'd stick to the one there.
Title: EA Trem ?
Post by: Paul Marossy on May 21, 2004, 10:48:32 AM
Soldering a 50K resistor across the outer lugs would make it roughly a 25K pot. I use that trick once in a while for 500K pots, since they are not so easy to find. I just take a 1M pot and solder a 1M resistor across the outer lugs. It seems to work just fine. I don't see why it wouldn't work in your situation.
Title: EA Trem ?
Post by: will on May 21, 2004, 10:53:42 AM
Hi,

Quote from: gezHere's another version of the EA:

http://www.runoffgroove.com/eatremolo.html

What is Q2 (JFET) doing in this circuit. Can it be replaced with diodes?

Regards,
Will
Title: Re: 1
Post by: Eric H on May 21, 2004, 11:42:23 AM
Quote from: u1061810Thanks for the reply, but I've got the G.G.G. board,and me being such a novice, I thought I'd stick to the one there.

The 50k pot will increase the range of the speed --I built mine when Greg N first uploaded the EA schemes, and  someone found that a larger speed-pot was good. Use 100k if you have it (read the notes on the second scheme).

Quote from: willWhat is Q2 (JFET) doing in this circuit. Can it be replaced with diodes?

Take a good look --the jfet is oscillating the bias of Q1 ;)

-Eric