# Traynor YBA-1 help please



## GuitarG. (Apr 1, 2010)

I have a Traynor YBA-1 amp coming too me. It has the choke transformer but no rectifier tube. It is going to need servicing. Cosmetically it's in rough shape. Both of the output tubes are a mismatch. As far as I know it does power up though and there is sound, so transformers should be alright.
It's not really an amp that I am familiar with. The only other Traynor I've ever owned was a late 60's YGM-3. Completely different amp. I'll be puting in new tubes and going over the circuit for any needed repairs and try it out as stock first. But without really altering the circuit too much to start, what common mods would you suggest to improve the sound from stock if any? I have read the most common is too change the volume pots to 1 meg audio taper and change the NFB resistor too 47k. 
Any other suggestions?


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## dwagar (Mar 6, 2006)

wait till you try it for awhile before you worry about mods. These are awesome amps right out of the gate.
Don't worry too much about mismatched output tubes, I'm actually running 2 different output tubes in one of my Marshalls, I had 2 "matched" pairs that weren't very "matched", so I matched my own pair by the bias numbers.


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## Geriatricrocker (Jul 20, 2009)

These old Traynor amps were made to survive the rental market, there arent likely to be any major repairs necessary, but check the filter caps, they are double section 40 -40 450 volt cans and while they were heavy-duty, now is the time to change them. While matching isn`t critical on these non hi-fi monsters, it couldn`t hurt, especially if you are choosing a particular tube type for a hard or soft sound. A lot of the old ones came with 7027A output tubes which were long discontinued ( although there are some Russian ones now, I believe) but the good news, you can replace with the more common 6550 or even a good 6L6GC. Traynor used to provide the schematic with the amp, check the protective aluminum cover for the chassis, if not, they are easily available at several sites for free. hese amps have a dummy load on the output stage so check your output transformer from before the resistor. don`t forget to drain the high voltage circuit before working on it. The only mod I ever made on mine was using a variable resistor on the bias voltage by varying from -35 vdc to -52 vdc could get much cleaner sound. Also removed the 47 pfd cap to make the guitar channel useable , although you may want to make it switchable .


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## GuitarG. (Apr 1, 2010)

Thanks for the replies. I haven't had a chance too play the amp a whole lot. when i first got the amp it had one of the original GE 6ca7's and what looks like a Siemens EL34. It also had 3 Phillips 12ax7's. Anyway the tubes are old so i pulled them. I will have too test them sometime.
I put in 2 newer SED EL34's and some JJ 12ax7's. I turned the amp on and everything seemed ok. No unusual sounds. Plugged a strat into channel 1 and turned up the volume. Almost all the pots are scratchy BTW. I'm going to need to spray them with cleaner sometime. When i played certain notes the amp would make some squealing noises or certain notes would become boomy sounding. After leaving the amp on and noodling with the guitar for about an hour or so all these unwanted sounds just seemed to eventually go away. I love the sound of it now.
The amp is a '71. All the circuitry appears to be original and untouched and match the schematic stuck too the metal plate shield. The cap cans are also original. Even though i don't hear any electrical hum and the amp sounds quiet I may change these anyway. What i noticed is channel 2 is much louder than channel 1. We're talking volume set at 2 on channel 2 is about the same as the volume set at about 7 on channel 1. Both have the 4 meg pots. Is this normal? The only other thing I noticed that I do not like is when I play the lower E string the bass seems to be a bit farty sounding when the amp is pushed into overdrive. Clean it sounds fine. I wanted too see how close this amp came too sounding like a plexi. An example of what i tried was cranking the volume to get overdrive and playing AC/DC's Back in Black with a humbucker guitar. All the chords sounded ok but in the verse part it does that little muted walk up on the low E string, that's the part that sounded a little weak or buzzy like there was'nt enough punch there.
Anyway I still need more time too mess around with the amp. As I said I haven't had a chance too play it all that much since I got it. From what I hear so far though, the amp sounds great.


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## GuitarG. (Apr 1, 2010)

Oh yes and I will be adding a bias pot when I get the chance.


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