Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Latole on January 06, 2025, 03:55:50 am
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Hello,
Owner of Traynor YRM-1 Reverb Master.
My question does your YRM-1 tremolo work like this one?
Long story short :
I repaired the tremolo which didn't work at all ( a solder ) .
I notice that the tremolo starts working from 5 on the INTENSITY button.
From 5 to 10 tremol sound normal, good.
It's a very special tremolo circuit, never seen anywhere else. Many circuits are close.
Thank's
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Uncle Doug have a video where he repairs an amp with very same behavior, effect only start working at 5,
Im not sure which video it was but ain't many with the tremolo topic.
Maybe this one:
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Thank's , I will search under Uncle Doug videos
Fender use another tremolo circuit . It will not help me.
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I did not find anything to help me.
Best is to have a feedback from an owner
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You need a strong 12AX7 for the trem to get it to start.
I'd replace C26 ecap, 125uF/16v, and check C23, C24, C25 to see if their leaking dcv.
Then check all the R's, including R20/R22 that feed the trem signal to the PI's output, to see if they've drifted. And if still not fixed, check C13/C14.
(Edit; I gotta stop stayin up so late. Those are the PI plate R's. :laugh:)
Check R39 by the trem foot switch, it's supposed to be getting -36dcv. Make sure there's a -dcv after R39, 1M R, between R39 and the trem foot switch jack. That dcv helps 'jump start' the oscillator. Fender does the same thing.
If it's not those things then it's probably the roach/bug.
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You need a strong 12AX7 for the trem to get it to start.
I'd replace C26 ecap, 125uF/16v, and check C23, C24, C25 to see if their leaking dcv.
Then check all the R's, including R20/R22 that feed the trem signal to the PI's output, to see if they've drifted. And if still not fixed, check C13/C14.
Check R39 by the trem foot switch, it's supposed to be getting -36dcv. Make sure there's a -dcv after R39, 1M R, between R39 and the trem foot switch jack. That dcv helps 'jump start' the oscillator. Fender does the same thing.
If it's not those things then it's probably the roach/bug.
Thank you Willabe,
All are done before.
All these resistors and caps are good . I don't take chance and put all news cap for test.
When R39 send -negative voltage ( with pedal jack plugged ) ; tremolo stop
With no pedal plugged / no - negative voltage ; tremolo work.
This tremolo is not same as a Fender or other Traynor wich I know pretty well, that is why I ask for a YRM-1 owner.
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A 100k resistor start the tremolo at 3.
An idea suggested to me by someone on Facebook
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In conclusion, the tremolo works in a completely normal way for a circuit with a photo resistor (LDR) because I was able to compare it with 3 other amps that also have LDRs, 3 Fenders, a Bandmaster, a Tremolux and a Vibrolux reverb, all in perfect condition.