JTM 45 & Bluesbreaker? Same amp?

Discussion in 'Amps and Cabs' started by illini, Oct 15, 2008.

  1. epluribus

    epluribus Member

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  2. illini

    illini Member

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    So what year did they switch to the 10.5" cab's. Or where do I find this info?
     
  3. illini

    illini Member

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    Is there a tonal difference between the 30 and 50 watt Bluesbreakers?
     
  4. illini

    illini Member

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    +1 I also want to know this.;)
     
  5. jumpnblues

    jumpnblues Member

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    Check out the Louis Electric version of the Bluesbreaker...killer tone.


    Tom
     
  6. 908SSP

    908SSP Supporting Member

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    Quoting yourself thats pretty funny

    Well there really is no 50 watt BB. Not sure what you're talking about. 50 watt combo my look like a BB but it is a 50 watt combo and any one calling it a BB doesn't know what he is talking about. Of course if Marshall does it it is pure marketing BS.

    So yes they sound different. The BB breaker is JTM45 with tremolo a softer cleaner bluesier tone. A 50 watt is a SS rectifier aggressive crunch machine depending on year and exact model of course they can go from the warm fat tones of the bass to the screaming aggressive tones of 72 lead.
     
  7. jmp

    jmp Member

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    I was a contributor to that website and spent many hours inside a BBRI chassis or two doing all the recommended mods.

    You actually can fit the Chinese KT-66s in the older 9.5" deep reissue cabinets (I did it on both of mine), but you will have to remove the chassis to do it as there is not enough room for the tube pins to clear the socket. Regardless, I would still hold out for the newer 10.5" cab if for no other reason than it just sounds bigger and richer.

    The tonal differences between a Bluesbreaker combo and a JTM-45 are due mostly to the types of speaker cabinets the two amps are usually played through. While the tremolo on the Bluesbreaker probably reduces the overall gain slightly, I don't think this feature alone would be enough to account for a dramatic difference in perceived tone. An open back 2x12" cabinet with 20 watt Greenbacks will sound different and break up earlier than a closed back 4x12" loaded with the same speakers.

    If I were to ever pick up another stock Bluesbreaker reissue it would be one of the newer 10.5" deep models. I would drop both filter caps down to 32x32uF, install a good set of KT-66 or 6L6 tubes, and swap the speakers for the Heritage G12M 20 watt Greenbacks. I would not mess with the circuit board or output transformer. If you're going to that much trouble you might as well go the boutique route or have a clone built from scratch. All those mods were developed back before there were companies like Germino and Metro building great clones at decent prices, so there are more options available now than there were 8 or 9 years ago.
     
  8. epluribus

    epluribus Member

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    Interesting. Ever happen to notice if the circuit components in the originals were same-sourced or were there indeed different suppliers involved, like transformers perhaps? OEM Bluesbreakers have always struck me as a bit gain-ier, but maybe BB players just run 'em that way cuz they sound so cool.

    --Ray
     
  9. illini

    illini Member

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    There is a guy locally advertising a 50watt Bluesbreaker combo, which is why I asked. Here is a quote from the ad. Did Marshall make a 50 reissue combo that looks like a bluesbreaker?

    "I have a mid 90's 50W bluesbreaker with (2) 25W greenbacks. Awesome tone and volume. Comes with vinyl cover. Amp is overall in good shape.
    Please email if interested"
     
  10. 908SSP

    908SSP Supporting Member

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    Yes that is wrong he means combo not BB. Look people make mistakes or take liberties with semantics all the time. 90% of peoples arguments are because of semantics. People wrongly use the BB for any Marshall combo from 10 watts to 100. Only the JTM45 tremolo amp in a series II cab can accurately be called a BB. The series I combo that EC had and lost in Greece should be called a Yardbirds combo because he recorded the BB album with the then new series II.
     
  11. jmp

    jmp Member

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    This is probably getting slightly off topic, but does anyone know which amp(s) Clapton would have been using for earlier Bluesbreaker recordings like "Telephone Blues" or the live version of "Stormy Monday?" I don't recall if those recordings were pre- or post-Greece. I want to say pre, which would indicated either a JTM-45 halfstack or the Series I combo. Granted it's an old mono recording, but "Telephone Blues" sounds like he's got a closed back cabinet (the low notes have a percussive "thump" to them that is not usually present with a combo).
     
  12. jmp

    jmp Member

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    I really haven't noticed. Since both circuits were essentially the same (save for the addition of the tremolo in the combos) I tend to think they would have wanted to stock as few component variations as possible to keep costs down. That's not to say a combo made one week might have different components than a head made three weeks later. The only thing consistent in those days seems to have been the inconsistency of parts availability. However, most of that inconsistency resulted in slight differences in small part values, such as caps and resistors. I think the only documented difference on the schematic is the bright cap on Vol. 1: 100pf on the combo vs. 500pf on the head, IIRC, which would make sense because the combo would have been lacking in bass response when compared with the head/4x12". A lower value bright cap allows more bass freqs to pass through for a fuller sound to compensate for the open back cabinet.
     
  13. Roe

    Roe Member

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    yes the model 1961 and 1962 "bluesbreakers" untill ca 1966 were jtm45 tremolo models in a combo
     
  14. Roe

    Roe Member

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    yes the latter are more aggressive, distorted and bright
     
  15. illini

    illini Member

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    Did they reissue the 50 combo's as well as the JTM45's in the 90's?
     
  16. Roe

    Roe Member

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    no, they didnt reissue the 50w combos. the 50w head was reissued as the 1987x
     
  17. Nolatone Ampworks

    Nolatone Ampworks Member

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    Just get 'em both and save that stone to defend yourself when your wife finds out! :eek:
     
  18. epluribus

    epluribus Member

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    Hey jmp, 'preciate the info. Sorry about the pokey reply, this thread fell under my radar for a while. Bluesbreakers are such cool amps IMHO, always interesting to peek under the hood and learn a little more about what makes 'em tick.

    --Ray
     
  19. Roe

    Roe Member

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    there are more differences as well:
    - some amps have mixer resistors bright caps but other dont (typically pa amps)
    - ot changed in late 65 from RS to drake
    - different tubes: 5881s, kt66s, el34s
     
    Last edited: Mar 10, 2011
  20. epluribus

    epluribus Member

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    Hey Roe, 'preciate the info. Fosse-natin' about those PA amps...IIRC it was Aspen Pittman that mentioned getting the PA head cheap and doing a couple of quick mods to turn it back into the guitar circuit. If only I could actually find one of those cheap PA heads... :)

    I was just crunchin' a couple of numbers to estimate the impact of that bright cap (that jmp talked about, above) on the freq response curves and then staring at Tone Stack Calculator trying to picture the sound from the plots. Interestingly, via some rough analysis, you can use Fender's digital tone stack circuitry in the dreaded Cyber Twin to actually model things like that--once you know what the respective plots look like you can take advantage of some CT menu quirks to actually audition mods. Sooo...that bright cap in a circuit feeding an open-back cab would make a modest contribution to the BBs unique character...IMHO, natch. :rolleyes:

    As for transformers and tubes, that's the sort of thing I'm curious about. If it were magically possible to establish which suppliers and sources were the most common in the JTM45 production runs vs the BB, I suspect we'd find more subtle culprits like those you mentioned. Slightly different parts, a different way of wiring, etc. As they say in the Formula 1 car-building biz, big changes make small differences, small changes make big ones. Always liked the wry irony in that observation. :)

    --Ray
     

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