Help choosing atranny

Completed amps from Fender, Orange, Hiwatt, Vox, etc.

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hebaton
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Help choosing atranny

Post by hebaton » Sun Jan 03, 2021 12:57 pm

HI, I just had a traynor TBA-1 lokked over and brought to MArshall layout buy Rick Onslow in Montreal. THe amp has a lot of sparkling higs and beautifull cleans...too clean ! THIs is supposed to be somewhat close to a JTM45 wich is fairly clean but I almost feel Like I have a Fender ( thar sound like a marshal if that can make sense ) I am going to swap output tranny but have no clue wich one to choose, can anyone suggest the correct one please ?

danman
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Re: Help choosing atranny

Post by danman » Sun Jan 03, 2021 6:29 pm

Both Metroamp and Marstran sell great replacement OT's but I doubt that a simple OT swap will give you the overdriven sound that you seek. So many factors such as the power tubes, the bias and the B+ voltage will affect the amp's final sound. Without some of these details it will be hard to offer suggestions.

These amps need to be played loud to get that great overdrive that we all love. Are you running the volume pretty high? Are you using single coils or humbuckers in your guitar?

danman
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Re: Help choosing atranny

Post by danman » Sun Jan 03, 2021 6:36 pm

Both Metroamp and Marstran sell great replacement OT's but I doubt that a simple OT swap will give you the overdriven sound that you seek. So many factors such as the power tubes, the bias and the B+ voltage will affect the amp's final sound. Without some of these details it will be hard to offer suggestions.

These amps need to be played loud to get that great overdrive that we all love. Are you running the volume pretty high? Are you using single coils or humbuckers in your guitar?

hebaton
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Re: Help choosing atranny

Post by hebaton » Sat Jan 30, 2021 7:50 am

Bias on El34s about 40ma for 435 plate voltage.
playing the thing at 5-6 an anything past thatm sound un pleasent. I do get some tube overdirve at tha volume but the caracter is not wat I hoped... will try KT66. Also installed a .68uf cap on the 840 OHMS R at V2A and split the V1 cthodes to install 2K7/.68 on bright channel...

Elad E
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Re: Help choosing atranny

Post by Elad E » Wed Mar 24, 2021 7:08 am

Put a PPIMV in that amp and you'll unlock the full range of breakup tones a JTM45 circuit can cope.

with the volume pot between 9-10 and the PPIMV anywhere below 3 o'clock I can get dirty tones I never heard out of my JTM45 at full volume by itself prior to the PPIMV, it can easily get into 80s territory despite anything else being stock (shared cathode, .1 coupling caps, KT66s, GZ34 rectifier, etc.) - I believe the PPIMV drives the PI tube harder than the preamp section can naturally do.

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