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EH question-Puretube to the rescue once again!

Started by jimbob, November 13, 2004, 11:54:46 PM

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jimbob

November 13, 2004, 11:54:46 PM
I have a Mini EH Q Tron that keeps making this wierd laser gun type sound no matter what string or note i hit. But it is also touch sensitive meaning the harder i hit the strings the higher pitch it makes. Looking at the board its simple enough. In fact , im suprised no one rev's this thing. Theres really not that many companents involved..Anyway, anyone have this problem before or an idea what might be the problem. Ill get an audio probe to it sometime, but i thought id see if anyone has heard of this before..I did see that it uses tlc2262cp...

anyone?

thanks
"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?"

aron

#1
November 14, 2004, 04:32:07 AM
Sounds like the "resonance", "Q" or "feedback" is set a little too high. That would explain that sound.

Is there a control for that or an internal trimmer?

bobbletrox

#2
November 14, 2004, 04:50:42 AM
It's a simple pedal is it?  I always figured it hadn't been traced because it must have been really complex.  I saw a pic of a mini qtron rehoused in a bb box on a website once, so maybe it's a candidate for DIY.

jimbob

#3
November 14, 2004, 11:50:46 AM
Aron- that sounds about right. I noticed the pot for that function doesnt make any difference when i turn it left or right. the other 2 outer knobs work though...hmmmm
"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?"

puretube

#4
November 15, 2004, 05:54:22 AM
is that again one of your "cheap finds" pedals?  :)

jimbob

#5
November 15, 2004, 12:37:56 PM
puretube- yuppers

I can always count on EH to keep me busy and in stock.
"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?"

puretube

#6
November 15, 2004, 01:27:18 PM
check the wires (prob. 2) from the Q-pot to the PCB - resolder them - ;
measure resistance of (de-soldered) Q-pot between wiper & ccw lug (should vary between 0 & 150k...);
if faulty, replace with 220k log. pot, and solder a 470k in parallell...

jimbob

#7
November 15, 2004, 02:28:13 PM
VERY COOL!!!!!!  

THANKS
"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?"

jimbob

#8
November 15, 2004, 04:54:16 PM
Puretube to the rescue once again!

It was a bad 150ka "q" pot. One thing ive learned from EH stuff is that  99 percent ot the time the circuit is fine ..its the mechnical end of it that fails..And thats not a bad thing really..Makes for an easy fix!!!!!

Thanks Puretube!!!!!! :D
"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?"

puretube

#9
November 15, 2004, 06:42:22 PM
you`re welcome "jb":
I dug up the schem my friend Mike Beigel comforted me with confidentially,
took a look where too much Q could originate...

sir_modulus

#10
November 15, 2004, 10:55:40 PM
What a freakin' coincidence!! Thats what happend to my Q tron. It sounds like there is a ton of gain on the signal, so it goes all high, and soft, then it adds volume as it comes back. I just resoldered the PCB mounted pots, and it works real good now. thanks!

Nish
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