Reviving this thread because the replacement speaker in the TR120 also blew. Well, it’s doing some weird fizzy stuff.
My TR35 is also in need of a new driver.
So let me get this straight - I should get an 8 ohm speaker for each amp (obviously with the appropriate wattage)? Both amps have the “minimum 4 ohm” warning on the external speaker jack.
The amps themselves work fine, I ran each of them to an external cab and they sound great.
TR120B speaker help!
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kennyhowes
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Re: TR120B speaker help!
First of all, hope you found a suited new speaker.kennyhowes wrote: Sat Apr 18, 2020 6:06 pm Reviving this thread because the replacement speaker in the TR120 also blew. Well, it’s doing some weird fizzy stuff.
Based on info around here (from John Hall), I thought to have understood the TR120B uses originally a speaker with additional terminals (an additional coil for some kind of feedback, so 4 terminals). Can imagine replacement speakers didn't have this, but then there'd be some unused wiring around, is it?
Curious. Also to see a TR120B schematic, how this was originally implemented.
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kennyhowes
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Re: TR120B speaker help!
I actually sold my TR120B and my TR35B shortly after this post, and moved over to a more powerful tube bass amp (a Vox V125B).
There's a schematic on the RIC website for a TR35B, but I don't know if there's one for a TR120B handy.
There's a schematic on the RIC website for a TR35B, but I don't know if there's one for a TR120B handy.
Re: TR120B speaker help!
Hi, Ah I see. Yes, I have the TR35B schematic, but the TR120B schematic isn't there.
It'll indeed be pretty alike, but the power-amp for the TR35B definitely doesn't use a 4-wire speaker connection (which the TR120B seems to use).
We'll see when I have the TR120B here, and when I'm able to lift the speaker. (Which I didn't force on the TR35B, speaker of that one also seems glued to the baffle.
)
BTW, since you had both types, I wanted to ask about that additional fifth control of the TR120B (w.r.t. the TR35B):
is this simply a level-control for the preamp out jack (so not affecting main signal path towards speaker), or is it some master-volume?
But just happened to find the answer somewhere, it gives the impression it controls the preamp-out level, but actually it happens to control the level of the incoming signal for the power-amp. OK.
It'll indeed be pretty alike, but the power-amp for the TR35B definitely doesn't use a 4-wire speaker connection (which the TR120B seems to use).
We'll see when I have the TR120B here, and when I'm able to lift the speaker. (Which I didn't force on the TR35B, speaker of that one also seems glued to the baffle.
) BTW, since you had both types, I wanted to ask about that additional fifth control of the TR120B (w.r.t. the TR35B):
is this simply a level-control for the preamp out jack (so not affecting main signal path towards speaker), or is it some master-volume?
But just happened to find the answer somewhere, it gives the impression it controls the preamp-out level, but actually it happens to control the level of the incoming signal for the power-amp. OK.