May 2009 \ Features \ 45 Degrees of Tone: The JTM45 Roundup

45 Degrees of Tone: The JTM45 Roundup

Steve Ouimette

Nearly 50 years since its creation, the Marshall JTM45 remains both a relevant and near-perfect example of what a great rock ‘n’ roll tube amp should be.
Premier Guitar May 2009
(3 of 8)



MetroAmp JTM 45 Kit and GPM 45 Custom Build

George Metropoulos is no stranger to the world of Marshall amps or to the online ampbuilding community. Having run MetroAmp for some time now, George offers everything from fully built replicas of many classic Marshalls to ready-to-build kits and hard-tofind replacement parts for vintage Marshalls. A player, George honed his amp-tech skills by adopting a DIY approach, taking care of his own amp repairs on the road. This extended into repair work at home, and then really took off when amps began coming in for restoration rather than simple re-tubing. After his ’73 Super Lead was stolen from a gig, he realized it might be best to leave the valuable amps at home, and so he embarked on a never-ending quest to replicate the tone of the old Marshalls.

Like all the builders in the roundup, George is passionate about vintage Marshalls and obsessive over the details that make these amps so coveted. We received two amps from Metro: the JTM45 kit (which can be purchased already assembled for an additional $400) and the GPM45, George’s custom-built JTM45 using NOS vintage parts. When we fired up the MetroAmp 45s, it was clear that they both came from the same camp. Both amps were meticulously built and incredibly precise in their layouts. The main physical differences between the amps came down to the caps, resistors and tubes. Both amps shared the same iron and layout, so they also shared a lot of the inherent tone in their circuits. As George is a fan of the mid-sixties JTM45s, Metro’s transformers are based on the Drakes, rather than the earlier Radio Spares iron. Still, there was no question that the GPM45, which included NOS Phillips mustard caps, Allen Bradley carbon comp resistors and a gorgeous set of Genelex KT66s, was sweeter sounding.

While those differences accounted for a tonal upgrade, what made the differences even more compelling was the way they affected the touch factor of the amp. Much like our ’65, the custom-built Metro had an ease about it that felt like a broken-in vintage head, making it a breeze to dig in, or to lay back on the strings and feel the amp act as an instrument. It was truly inspiring. Of all the amps in the roundup, this amp sounded most like our ’65—frighteningly close! I should mention that the Metro kit version was actually plugged in first, and before comparing it to the GPM45, we all agreed we’d be thrilled to have one in our collection. We may be splitting hairs here to some degree, but knowing that anyone can buy a complete kit for under a grand, and have that kind of quality and tone—that says a lot.

metroamp.com

JTM45 Kit:



GPM 45 Custom Build:




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Comments

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BobC
on 03/23/2013 		@W.A.Looker Because they were named JTM45 due to the fact that they had a max output of 45watts. As measuring the power of guitar amps became more about a standardized RMS measurement and less about marketing fluff the "real" wattages started being used. People around when the JTM45 was created still know it as a "45 watt" amp even if under the more accurate measurement it is not.
W.A. Looker
on 10/25/2012 		Why does everyone and I mean EVERYONE insist on saying that these are 45 watt amplifiers??? The clones might very well be, but on Marshalls own site it says that the reissues are 30 watts. It might not mean much to some, but if you are going to put it in writing, be accurate.
Joe R
on 08/13/2012 		I have a 97 Re-issue (pcb) which performed extremely well for the past 10 years. Currently the board is being replaced with a Ceriatone turretboard unit and 5881's with KT66's. (all due to a funky colored burn on the pcb and strange microphonic type squeal (not affected by tube change in preamp). Can't wait to ressurect this beast!
paul
on 01/02/2012 		I live in the UK and bought a JTM45 re-issue new, less than half the price of any of the clones here. And of course I supported British jobs cos the amp is MADE IN BRITAIN. Unfortunately, CELESTION SPEAKERS ARE CHINESE and as such are NOT British. My JTM RI sounds great. I think no amount of amp tone can make up for the tone you get from your fingers, so i am not even gonna read these reviews, I am going to PLAY.
de
on 03/16/2011 		i have a jtm 45 reissue from the mid 90's. the original printed board is replaced with a doug hoffman marshall plexi-style point-to-point board and the amp builder had to increase the caps sizes a bit. it's now using 2 el34's, but i want to go back to using paired 6l6's/5881's. in my opinion the jtm 45's have a more mellow, less edgy tone than the jtm 50 w plexis, even when keeping the tube rectifier in there.
Andrew
on 08/23/2010 		I have a JTM 45 reissue from the early 90's. This is the last model with the original Drake transformer.. Whoever says the Metro amps and all boutique custom built shit overtaking mine: thick bullshit. 6l6 sound darker indeed than EL34 but this particular baby really smokes... Tried Metro, Germino, Ceriatone, etc.. they are all good, but cannot really tell the difference sound-wise blindfolded.. SG, good cable, JTM 45 cranked, maybe throwing a fulldrive 2 in front of it, man you would love it!
Peter
on 07/24/2009 		Just in reply to the man who said we are sheep... you're right :-) When you look at players in the sixties they were doing all sorts of wierd mods, slicing speakers because the distorted sound was groovy baby.... but they also used dual showmans, hiwatts, FUZZ boxes :-) My favourite amps at the moment are a Marshall DSL100 and Fender (red knob) Dual Showman head and they do everything, plus more, that I want... for another bloke it would be a Fender Twin or a Boogie... Don't get me wrong, these were great amps in their day... and when pushed they crank today... but again it's funny making big money from old technology...
Peter
on 07/24/2009 		The reason why companies change their product is competition... idiots wanted more and more gadgets built-in to the amp... channel switching, overdrive, reverb, FX, lighter amps, etc... or be left behind in the rush...

You can't beat ONE great tone... and then play around with that... add one great guitar... and a guitarist with "the touch" and bingo... If I became a Satriani on guitar and used a TSL601 combo... and young pups looked up to me... they'd re-issue the TSL in 20 years time :-)

Cheers!
Frank M
on 06/24/2009 		One thing I think needs to be pointed out about the Marshall Reissue in this roundup is that looking aththe PCB you can easily see that the circuit was totally modded from the original JTM45 circuit with those larger caps and how they're wired up as well as the fact that the orignal came with 5881s not EL34s so that was a mod as well. Still a great article and about the only one out there that compares them. Now if we could have a good Plexi 100 watt round up would be really great!
trippin
on 05/29/2009 		Skeptical of "reissues"? Why did people stop making them? Easy. Making short term cost improvements and the typical kinds of model "upgrades" dictated by a competitive marketplace. The same reason Les Pauls were made with pancake bodies and poly finishes. So I'd say rather the opposite: the sheep were the ones lured to what was peddled as the latest and greatest iron at that point in time. Even the Beatles went all transistor, didn't they? Sputniks and all that mod stuff! That was like the cool thing: "Solid State." Since then we reflected on our musical history and discovered that, hey, whoa, we really liked those old records for a reason. Not everyone, mind you, but some. It's a conscious decision and a conscious goal that has nothing to do with wool bearing mammals, and it's not everybody's bag. So if it's not your bag, that's cool. But no one is "amending" the past. To the contrary, we're recreating it as true to original as possible. We do this because we HAVE learned the lessons of the past. You've got it all backwards, man.



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