1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

[muttznmongrelz]

Ran across this locally and played it enough to be impressed and pick it up yesterday. Reminds me (as it should) very much of the 1978 Marshal JMP 50W 2x12 Greenback Equipped Combo I had for about 13 years. Tolex tears and grill cloth has some holes from the speaker mounting screws poking through; cosmetic wear from gigging but it sounds amazing!

[jeremy]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

sweet man. never played a ri but i know a guy who had an old one and it was great!

[muttznmongrelz]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Thanks. Not a lot of info on these other than a handful that have sold in eBay and Reverb. Going to look into it a bit more this weekend as to confirm type of tubes, etc. as I'm seeing a few spatterings of info - some indicating hand-wired, some indicating EL34 tubes, etc.

Here's what I think applies to it: Serial #V00733, Made in England, 50 watts of EL34 tube power through two 12" Celestion Greenback Ipswich Speakers, top mount controls, heavy duty caster wheels, foot-switchable tremolo.

[jeremy]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

i assume you mean el34

[muttznmongrelz]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Ha! Yes Sir.

[Lake Placid Blues]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

If it is a (year) 1989 reissue, then it shipped with 5881 power tubes with output at clipping of 30 watts. 5881s are used in place of KT-66s on the reissues because there were no current production supply for KT-66s in 1989. The originals in the 60s had KT-66s. Nevertheless, running EL34s in them is pretty common and doesn't hurt anything. (Marshalls almost always have pins 1 and 8 externally jumpered and the stock power transformers handle the heater current ok) There is an impedance mismatch, but there was on the original KT-66 amps as well. I like JTM45s and BBs with EL34s myself.

The amp should have a PCB with chassis mounted components and flying leads. However, installing turret boards in place of the PCB as well as after market transformers was/is a popular mod.

[jeremy]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

i thought the later originals had el34s? didnt marshall start switching over in '66 and by '67 everything was el34 or am i off on that

[muttznmongrelz]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Tried getting some pics...no idea what I'm looking at...am I correct in this being a 1962 Model?

Drake Transformer 11/89


Sovtek Russia


Mesa 6L6


LCR UK


Only finding a few of these out there...hand-wired?

https://reverb.com/item/4057331-marshall-jtm-50-watt-tremolo-bluesbreaker-combo-amplifier-1990?gclid=Cj0KEQjw2fLGBRDopP-vg7PLgvsBEiQAUOnIXDz3x3twGtNP5C26mEP1ksvQ-A9jqlSUh86cvUwoOK4aAt_z8P8HAQ&pla=1

[Lake Placid Blues]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

i thought the later originals had el34s? didnt marshall start switching over in '66 and by '67 everything was el34 or am i off on that

Your correct. During 1967 they were transitioning from KT-66 to EL34 tubes. The JTM45 amps with EL34s are now called JTM50s. Once the tube rectifier was dropped they evolved into the 50 watt plexi. JTM50s had an output transformer which matched the impedance of EL34s. The re-issue is based (mostly) on the KT-66 versions.

[Lake Placid Blues]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Tried getting some pics...no idea what I'm looking at...am I correct in this being a 1962 Model?

Drake Transformer 11/89


Sovtek Russia


Mesa


LCR UK


Only finding a few of these out there...hand-wired?
https://reverb.com/item/4057331-mars..._z8P8HAQ&pla=1

The Mesa STR440 tubes are 6L6GC tubes which are of the 6L6/5881 type. The KT-66 is also a 6L6 type. The output transformer part number 784 339 I don't know. The 50 watt OPT part number for EL34s is 784 139, and the KT-66 opt part number for JTM45s is normally 784 103. This might be for 5881s?

That is the original filter cap for the reissue.

It might be good to replace the output tubes with kT-66 and re-bias, but if it sounds great maybe don't worry about it.

On edit: the Sovtek is the GZ34 rectifier tube. The corner position is the rectifier tube position.

On further edit: KT-66s might not fit in the 89 cabinet?

[Lake Placid Blues]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Only finding a few of these out there...hand-wired?

Yes, but with a printed circuit board instead of a turret board, stock.

[muttznmongrelz]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

Appreciate the insight and info LPB. I was fortunate enough to run across the gentleman who owned it for most of it's life and he indicated that it could probably stand a re-tube and re-bias this point and I've run across a good amp shop locally so I'll probably take it in for a once over.

I am digging the sound as I got an opportunity to plug in, turn it up and play it for a while last night. First impressions were that it is no where near as loud as the old '78 JMP 2104 Greenback Equipped 2x12 Combo that I owned for 13 years but a very pleasant tone and is a touch sensitive/dynamically responsive amp.

[dystrust]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

On further edit: KT-66s might not fit in the 89 cabinet?

The reissue cabs aren't as deep as the original amps, so it's entirely possible that KT-66s won't fit.

[PFDarkside]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

The reissue cabs aren't as deep as the original amps, so it's entirely possible that KT-66s won't fit.

I simply don't understand this. When it's a capacitor that hasn't been made in 30 years or speaker magnets that aren't available I'd get it... but dimensions on a simple cab? Why not just get it right?

[beaubrummels]

Re: 1989 Marshall JTM Tremolo 50 Bluesbreaker 2x12 Combo

That looks like a really nice, fun amp. I could really use an amp like that for local gigs and playing out. Nice one.