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Old 13th September 2012, 05:58 PM   #11
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I swapped both the cathode resistor and cap. And now it is at the proper voltage per schematic. Problem persists......
When the trem is bypassed I still get a distorted signal when playing moderately hard.
Also the Trem is chopping hard (ticking) when intensity is past 3 on control.Could it be the whole trem section or just the caps? What do yall think???
Could it be the tubes???? I checked them on a tester and they tested good.
Trying to narrow it down with voltage inspection. I will tinker more tonight and see if i can track it down.
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Old 13th September 2012, 06:04 PM   #12
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Try removing V1 and play through it. You dont need that tube just to make noise.
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Old 13th September 2012, 06:10 PM   #13
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Pulled that tube and played same ills.
Hmmn?????
Even though my voltages are in line with specs at the filter caps. Could the can be causing the problem.
It has that slight wave phasing in the noise floor. Similar to the sound of tuning an old am radio.
And of course the fuzz when I strike hard on the strings. What could it be??????
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Old 13th September 2012, 07:36 PM   #14
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Is there any chance you can post up some sound clips?

Even if its just recorded from a mobile phone, so long as the sound from the mic stays clean, it might give us a better idea.

Chris
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Old 13th September 2012, 08:38 PM   #15
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Sure I will later tonight. If I can figure out how to attach them!
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Old 13th September 2012, 08:47 PM   #16
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I worked on a bunch of Ampegs. They use some of the worst random surplus caps I have seen in gear of this quality. FIRST thing I would suspect is coupling caps. What is in there for caps?

The green transparent Wimas are usually ok but Tiny Chiefs and those green plastic Sangamos are very dubious.

Also if the filter caps are shot, which is a very good bet, you could have all sorts of odd oscillatory effects due to deficient decoupling. This seems to be in accord with the symptoms you report.
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Old 13th September 2012, 09:44 PM   #17
Enzo is offline Enzo  United States
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Fix one thing at a time. Turn off the trem and fix the distortion. THEN go back and fix the trem.


A rule in my shop is FIX the amp first, THEN go back and update parts. If you start swapping out a lot of stuff "as long as I am in there" but without having made the amp work, you are just adding that many more opporunities to cloud the original problem and its solution.
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Old 13th September 2012, 09:48 PM   #18
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Quote:
Originally Posted by Enzo View Post
Fix one thing at a time. Turn off the trem and fix the distortion. THEN go back and fix the trem.


A rule in my shop is FIX the amp first, THEN go back and update parts. If you start swapping out a lot of stuff "as long as I am in there" but without having made the amp work, you are just adding that many more opporunities to cloud the original problem and its solution.
Enzo - well spoken.
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Old 13th September 2012, 10:03 PM   #19
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Thank You All So Very Much. Your insight is priceless and correct!!!
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Old 14th September 2012, 04:12 AM   #20
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After much, much tinkering the problem persists. I change the filter caps. To no avail. Still producing a fizzy fuzz when played hard. There is a small window of clean tone before it gets thrust into cutoff and distortion. Has anyone ever experienced a OT acting like this. I get a good volume and definitely audible amplification. So assume the OT is fine. Not sure where to proceed except rebuilding the preamp in hopes that it is the caps in that section.
It produces fuzz then when signal amplitude goes down it hits a gate point where it is no longer fuzzy.
Hmmnnn. Any thoughts
Thankyou
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