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DIY Stompboxes => Building your own stompbox => Topic started by: dubs on March 15, 2004, 11:44:50 PM

Title: GGG EA tremolo correction & debug question
Post by: dubs on March 15, 2004, 11:44:50 PM
Correction: wire from middle lug of speed pot should be connected to ground (the right lug). Wiring the other way as on layout makes got turn in reverse.

Question: What is additional transistor for in the new layout to the older layout?

Debug: Made the GGG layout, wired it for led pulsing which works o.k. I get signal coming thru loud and clear when effect is on but no tremolo effect (but can hear faintly in the backgorund). I perhaps question the wiring layout of the depth pot on the new layout as it seems different  to the old geofex layout.
Title: GGG EA tremolo correction & debug question
Post by: aaronkessman on March 16, 2004, 09:18:24 AM
i built the old version from GGG. have not tried making the pulse LED function, but i plan to.

that first transistor is a buffer stage. the version on runoffgroove.com cindenses that circuit back down to 3 transistors by (somehow) using that first transistor for a buffer too.

hope this helps somwhat ;-)

aaron
Title: GGG EA tremolo correction & debug question
Post by: dubs on March 16, 2004, 05:12:40 PM
Thanks, got it working o.k. Found using Mpf102 transistors in Q2 and Q4 had little tremolo effect , then replaced with 2n5457 in Q2 and it worked o.k. Strange as I built geofex 3 transisotr layout and MPf102 worked o.k.

I did the pulsing led by soldering a led & 10k resistor on r8 (15K) and changing R7 to 390k resistor.