Marshall JTM-45 with a Attenuater - HELP!!

Discussion in 'Amps and Cabs' started by Robert123, Mar 17, 2006.


  1. Robert123

    Robert123 Member

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    I have been craving the feel and look of a Marshall JTM45 for awhile now. However, I have been using 18 watt amps so much lately for low stage volumes.... I'm not sure how much louder a JTM45 will be.

    The whole band is put through the PA night after night and the lead singer uses in-ear monitors for all live shows. Do you feel the JTM45 will sound good and tamed with a attenuater? I have never used a attenuater so I'm not really sure how it will work for a simple amp design like JTM.

    Any help on this amp with a attenuater is highly appreciated.
     
  2. trisonic

    trisonic Member

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    If you play the 18 watter cranked the JTM45 is actually not that much louder.
    JTM45's (well, the originals) have a very pleasant soudning volume - if that makes any sense.....

    Best, Pete.
     
  3. Jonster

    Jonster Member

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    Hi,
    New around here, but been playing 31 years, 69 amps so far, multiple attenuators. :)

    The bottom line: no matter what anyone may claim, IMO (a strongly voiced opinion) - ALL attenuators affect the tone, depending on the amp/atten. the affect can be profound. That being said: what would be the biggest diff. between your "un-molested" 18 watter, and an attenuated JTM??

    IMO, the 18 watter will be zingier, have more top end, and sound more immediate. (some of this is simply the circuit differences) The attunuated 45 will sound like a 45, but it will lack that immediacy, and sound somewhat congested. Not a bad thing per se, but a markedly different thing for sure. The speaker(s) will not be behaving the same way, and that is a MAJOR factor in tone. Now, I have succesfully run attenuated rigs live (most notably a 72 JMP50 head, 2x12 cab), and my fav box is a Weber. I think the dummy speaker motor does alot for the feel-factor. But, the Weber eats treble, and bass....make no mistake. As for the 45 being about the same volume,......maybe on a meter, but to my ear,....chances are you'll be asked to turn down a healthy JTM45 at volume. It really is just a trial & error thing. Some folks DETEST attenuators, some guys swear by em. Me: to be honest, mine is gathering dust, has been for some time, and I have an amp that needs it. It bugs me. YMMV
     
  4. michael patrick

    michael patrick Supporting Member

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    How loud the JTM45 will be in relation to the 18-watter will in part be determined by what kind of and how many speakers you'll be using. If you run the 18-watter through one 12" speaker and the JTM45 through a 4x12 (my preferred rig, by the way...) the 45 will be quite a bit louder. But if you run them both through a single 12" the JTM 45 won't be that much louder. A 45 is only putting out 34-36 watts, about double the 18-watter. The rule of thumb I've seen says double power gives you 3db more. Or something like that.

    I use a Hotplate with my JTM45 clone (a Mojave Plexi 45). With one or maybe two clicks down on the attenuator ought to get your volume with the JTM45 in the neighborhood of the volume on your 18-watter.
     
  5. CAFeathers

    CAFeathers Member

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    I have run my Marshall JTM-45 RI through several different attenuators (Weber MASS, THD Hotplate and one other) into a 2x12 cabinet and although the volume level was much lower I really didn't care for the tone. The attenuators muddied up the JTM-45.
    Fewer speakers and use of the volume controls will probably do you much better.
     
  6. GuitarJoe

    GuitarJoe Member

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    Great post Jonster! Posts like yours is what makes a forum like this excellent. Hope to read more of your informed and valuable posts in the future. Thanks.

    GJ
     
  7. jkr

    jkr Supporting Member

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    You nailed it!
     
  8. big mike

    big mike Fixed Bias Moderator Staff Member

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    Really depends. If you're just trying to knock of 3-6 db, it's no problem, and should work fine. If you're attenuating heavily, then all bets are off.
     
  9. MLG8675

    MLG8675 Member

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    Having recently picked up an 87X and a THD hot plate, I'd have to say i'm quite pleased with the results through my 4x12. In fact, I think I prefer it to my MV Marshall (although things tend to even out when both are sufficiently cranked). A quite acceptable tone can be achieved with even a fair amount of attenuation. Like most would and have already agreed, that more attenuation= more tone sucking. One caveat would be that some amps may not agree with attenuators or particular types of attenuators. So do your homework and go for it.
     
  10. Robert123

    Robert123 Member

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    The question that has been asked many times. But taking note of what a new JTM-45 RI costs verses a somewhat vintage Marshall made before 76'..... is there a very noticeable sound difference? Will I really have to listen closely for the difference or has the Reissue verses vintage somewhat been blown out of proportion?
     
  11. Jonster

    Jonster Member

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    Robert,

    Having owned a RI, and having played an original, I can state that to me, the RI did a pretty decent job at getting the the tone one expects from a JTM45.

    However, as is the case with may a RI vs Original comp., there were differences, and unfortunately they were magnified as the volume increased and the amps were pushed. The RI to my ears is stiffer, more strident when pushed. The drive is not as fluid. It is a tad tubby compared to the original, lacking just that extra hint of mid range sweetness. I think with a wise pedal choice, and some carefull tweaking of the dials this could be minimalized. Also many speak of the tube change to KT66's, and I am sure that would help as well. Now, cost considered, would these tonal differences keep me from owning another RI? NO. I think it's a great amp for what it costs, and if I wanted to just about nail the originals tone, I am pretty sure I could. You probably could as well, with little effort. Will it ever be %100 dead-on? Probably not, but the gap can be marginal. I had alot of fun with that amp. Squishy, fat, bold, zingy......LOVED my Teles.

    (I ran old greenbacks)

    The attenuator thing with that amp, to be honest, I would sooner run a good OD to push it a bit, and dial-back whatever frequencies the OD exagerated rather than attenuate. I think alot of the immediacy of that amp would be crushed by attenuating it. Just my 2 cents. YMMV :)
     
  12. Robert123

    Robert123 Member

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    Thanks Jonster I found what you wrote very informative.

    Another question that has been confusing my decision making is other Marshall clones like Germino, and Mojave etc.... Are they a better bang for the buck? Or if you want the Marshall sound get a Marshall?
     
  13. Jonster

    Jonster Member

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    The Germinos I have heard are just killer. (dare I say sound BETTER than most Marshalls I have heard) Yikes!....shhhhhh.

    If I was going to go the Marshall route again, that may be my #1 stop, honest.

    However, I can relate to the die-hard, "stick to the original" thinking, as despite large amounts of $$ I have spent on other "clones" (AC30's, various Fender circuits), I still end up with the "real-deals-amps", and like them better. Again, this is me. And again, Germinos just plain kick-butt, period. My last Marshall, a 73 JMP 4 hole, would have been easily beat by many of his models. (now, is the Mojo-factor the same??.....nope)

    My advice, PLAY some amps if ya can. Remember as well: every Marshall is like a fingerprint, no two the same. In fact, you have a FAR better chance at consitency when looking at the RI's, or newer amps like Germinos. I have played several vintage Marshalls right next to eachother, 50 watters, Super Leads, and they sounded WAY different. Same with Fenders. You just happen upon the good ones, or roll the dice on an ebay amp. They can be dogs, despite the pedigree!!! Buyer beware!
     
  14. MikeyG

    MikeyG Supporting Member

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    I just started a related thread, and said the exact same thing: at -3 or -6db, most attenuators work reasonably well. Beyond that, they suck tone hard.
     
  15. hamrhed1

    hamrhed1 Member

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    I have a Rockytop 18 1X12 G12H and a Germino Classic 45 + 2X12 G12m Heritage speakers and these are good descriptions of both of them. They are both friggin loud for around the house BUT...they sound fantastic. I also find that I am happier with the 18wt's level of gain with no pedals. The 18wt on 6-7 has a nice grind with no pedals. To get the sound I like from the 45, I crank it up to at least 8-9 on the bright channel and then hit it with a Fulldrive II. When driven like this, it's big and fat and round and not a bit harsh. Back off on the volume and you have a nice "hairy" clean, crank the volume and it's classic rockville with lots of sustain. The point is that even though the 45 isn't so much louder than the 18, I always seem to use most of the extra volume because to my ear...it just sounds better and bigger when the 45 is hit with a Fulldrive II AND being driven hard. I have a Dr Z attenuator and it does work well with the 45 for the first few clicks. I also use low efficiency Heritage speakers and I have ClearSonic shields. All of this helps.
     
  16. Robert123

    Robert123 Member

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    That is a good price on the Rockytop 18. Is there tone and build quality as good as some of the other Marshall clones out there? Where are they cutting corners to almost bring the price down a grand?
     
  17. hamrhed1

    hamrhed1 Member

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    The Rockytop sounds fantastic and seems well put together. It seems to hang well with my Germino Classic 45 and Masonette in the tone and fit/finish dept. I believe others here have stated that the parts used in amps by both builders are of simlilar quality.

    I think that the Germino warranty is longer than the Rockytop warranty.
    Greg at Germino and Jesse at Rockytop are both top-notch to deal with.
    Both builders will tailor the amps to fit your needs and provide speaker types and configurations/tolex-grill cloth options that aren't available with Marshall too.

    I don't think these guys are cutting any corners...I think they're just hungrier than a company the size of Marshall.
     
  18. myles111

    myles111 Member

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    Pete,

    You are correct.

    Cathode biased amps have more (or different) harmonic content so they will seem louder for a given wattage. This is one reason a Fender Twin Reverb at 85-100 watts is no louder than a "30 watt" Vox AC-30.

    My Dr. Z Carmen Ghia is louder than my own JTM-45 which benches out at about 38 watts.
     
  19. John Phillips

    John Phillips Member

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    To get a JTM45 down to 18-watt level only needs 3dB attenuation. You can achieve this very easily by running your attenuator as a parallel dummy load, which is more tonally transparent even than a normal -3dB setting. Just set the attenuator to 'load' (or to maximum attenuation if it doesn't have that), set the amp to half the impedance, and plug the attenuator into the second speaker jack. Now you effectively have two 'cabinets', one of which is silent but is still taking half the power.

    FWIW, I much prefer the sound of a mildly attenuated JTM45/JMP50 etc to a cranked 18/20W, at the same final volume. The big amps just have a depth and complexity that the little ones don't.
     
  20. michael.e

    michael.e Supporting Member

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    That is great info! Thanks!

    Much agreed, that is why, when I did have to downsize, my Reinhardt JTM45 stayed. Perfect club amp and selected outdoors venues
     

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