EA Tremolo build problems (Dragonfly layout)

Started by superferrite, May 09, 2011, 08:51:54 PM

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superferrite

I had this vero populated for months and finally got it together.
Results are a booster that sounds damn good, and no trem effect whatsoever.
The blinking rate LED stays on all the time, once I flipped it (as per various posts here).

Layout located here:
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album19/album145/EA_TREMOLO_VERO.gif.html

Dual rate mod (accomplished by a dpdt switch) found here:
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/The-Mod-Zone-_/EA_rate_mod.gif.html

Circuit from Runoffgroove here:
http://www.runoffgroove.com/eatremolo.html


Voltages:
Q1
D 6.02
S 1.41
G 0.73

Q2
G 0.038 (then nothing, next check)
S 0
D 0

Q3
C 6.4
B 0.51
E 0


UGH!
Anyone see what might be a problem?   I tried two different jfets...

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superferrite

Nobody has built this?   The search function isn't really helping me on this one.

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superferrite

Bumpage.  I think it might be a bust?!?!?
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ode2no1

i tried building this on a GGG circuit board a few years ago and couldn't get it working either. all i got was a boost as well. i do remember not having the correct pot values (all of them were above what the circuit calls for), but yeah...never once got any trem out of it. i wonder if it's a super finicky circuit or if i just made a mistake somewhere. that was easily my most frustrating build...especially since it was going to be a birthday present for a friend haha. anyway sorry i can't offer any advice. just figured i'd share.

superferrite

Thanks,
I might just build another Colorsound Tremolo.  I know they work, at least until I break them.
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superferrite

What the hell, one more bump for the road.
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mistahead

I know that people have sucessfully made this, I haven't but others have...

Go through the basic modular steps - boost stage works, indication from the lack of trem and solid LED would indicate that modulator is not working (nothing you didn't know there).

Without being well versed in electronics yet - how does the modulator modulate? What is the working stage MEANT to do and HOW? Does it throttle voltage or vary otherwise...

Did you pull the rate mod and just check it "stock" to confirm something wasn't going pear shaped at that point?

McKenzy

I've built this and had the same problem. I had left a tiny hairline of trace on one of the cuts between the transistors. Check around there, that's all it took and it worked instantly. 
( Apart from flipping the LED as said). And 4.5V from trimmer.

superferrite

Thanks guys.   Not what the problem is, but I'm researching what makes the trem oscillate and that is sure to help.
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