I am replacing the electrolytics on a 1974 Tryanor YGL-3 Mk 3
After cleaning the post and having replaced most of the electrlytics ( some are on order ) I have a few issues with the amp.
THe "normal" channel is very weak, low volume and the range of intensity for the tremolo only starts around 5 or 6 on the dial, the lower part of the pot's rotation there is no effect.
Working with a full set of known good preamp tubes. Need to know if I should remove the ground switch, amp has a 3 prong cable installed.
Very weak channel and intermittent Tremolo !
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Very weak channel and intermittent Tremolo !
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Last edited by hebaton on Sat Jan 10, 2026 2:36 pm, edited 1 time in total.
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Stevem
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Re: Very weak channel
So what do you have for voltages on pins 1,6,3 and 8 of V1a and V1b as compared to the schematic, assuming your heater voltages are of course good on that tube.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Very weak channel
Here you go: pin 1:162 6:157 3:1.2 8: 1.2
Tried a new 12ax7 again this morning, no change.
Also, the Tremolo didn't come on when I turned on the amp after it sat off all night, then after10 minutes it came on suddenly when I turnedthe Mids up on the channel..,
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Stevem
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Re: Very weak channel and intermittent Tremolo !
Sorry, it was the voltages on v2a and V2b I should have asked you for, and this time please include checking pin 2.
Does your reverb sound like it’s working at all?
Does your reverb sound like it’s working at all?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Very weak channel and intermittent Tremolo !
So, On V2 readings prettu similar pin 1:152 2: 0 3:1.2 6:150 8:1.25
V2 drives the effects channel and yes the reverb works fine. If anything I would like to tame the highs on the return from reverb, I find it very bright.
About the Tremolo, I tried taking some readings there on V3 but with a tube in place, pin 1 voltage is very unstable, pin 6 reads in the 230v area others are difficult if not impossible to read. With the tube out I get 325v on Pin 1
There are still afew old electrolitics in place in the amp. The ones on the bias supply, the 2 10@400 found at C22 and C26 also a 125@16 at C27
Last edited by hebaton on Sat Jan 10, 2026 4:27 pm, edited 1 time in total.
Re: Very weak channel and intermittent Tremolo !
Yes. Remove the ground switch. Ground switches are a known way to electrocute the player if the cap fails.
Then check to see if the 3 wire cable is installed correctly. Using your ohmmeter, measure the resistance from the ground prong of the AC cable to the chassis, the bushings of the input jacks, any metal the user might touch. Should show a very low resistance. Then, for kicks, measure the resistance between the AC line and neutral prongs to the ground prong in both positions of the power switch. Should show very close to an open circuit, much more than a megohm.
"For every complex problem there is an answer that is clear, simple, and wrong"
H. L. Mencken
H. L. Mencken
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Stevem
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- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Very weak channel and intermittent Tremolo !
None of the caps you listed in your last post will have any to do with the Tremolo issue.
If you have not changed out C12 yet then I would do that along with any of the other non electrolytic caps in the Tremolo circuit, or at least change out all the caps off of the plate of V3 b
If you have not changed out C12 yet then I would do that along with any of the other non electrolytic caps in the Tremolo circuit, or at least change out all the caps off of the plate of V3 b
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Very weak channel and intermittent Tremolo !
Thanks, i'll do that. What about the normal channel being so weak, any clues on that ?Stevem wrote: ↑Sun Jan 11, 2026 11:49 am None of the caps you listed in your last post will have any to do with the Tremolo issue.
If you have not changed out C12 yet then I would do that along with any of the other non electrolytic caps in the Tremolo circuit, or at least change out all the caps off of the plate of V3 b
Re: Very weak channel and intermittent Tremolo !
Tremolo issue could also be caused by a bad optocoupler.
...Steve
Re: Very weak channel and intermittent Tremolo !
CAn anyone suggest a mod to tame the highs from the reverb ?
Re: Very weak channel and intermittent Tremolo !
Will try that in the morning.
I am finding thai amp very brght in general. On the effects channel, I woulder inf there is something similar to a marshall plexy bright channel going on, if there is something I could change to tame that down a bit that would be great, just don't know what to look for. Also, still cannot figure why the normal channel is so weak, any clues on tha would also be vey much appreciated.
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Stevem
- Posts: 5604
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Very weak channel and intermittent Tremolo !
Why don't you do all of use who are trying to help you a favor and post up a schematic of the model amp right to this string of post.
Why don't you try this .
On V1A and V2A remove both wires from pin 6.
Then run a wire from pin 6 on V2A to the wire you removed from V1A.
Does the low output issue you have stay with the normal channel?
Why don't you try this .
On V1A and V2A remove both wires from pin 6.
Then run a wire from pin 6 on V2A to the wire you removed from V1A.
Does the low output issue you have stay with the normal channel?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Very weak channel and intermittent Tremolo !
Sorry, I got confused with a previous post where the schematic is aready posted. Here it is .Stevem wrote: ↑Tue Jan 13, 2026 9:37 am Why don't you do all of use who are trying to help you a favor and post up a schematic of the model amp right to this string of post.
Why don't you try this .
On V1A and V2A remove both wires from pin 6.
Then run a wire from pin 6 on V2A to the wire you removed from V1A.
Does the low output issue you have stay with the normal channel?
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Re: Very weak channel and intermittent Tremolo !
Explanation for my proposal regarding C20:
This cap forms a resonant circuit together with the inductance of the reverb transducer resulting in a treble boost of the reverb signal.
Fender started using this method to brighten up the reverb with the SF amps.
This cap forms a resonant circuit together with the inductance of the reverb transducer resulting in a treble boost of the reverb signal.
Fender started using this method to brighten up the reverb with the SF amps.