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

45 Degrees of Tone: The JTM45 Roundup

by 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
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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.

It was originally built around the design of one of Jim Marshall’s favorites, the Fender Bassman; like the Bassman, the JTM45 was actually a fantastic guitar amp. Because of its consistent popularity, Marshall has offered a reissue version of the head— more than 20 years after production of the original JTM45 ceased. While the reissue is built with modern components and assembly techniques, it retains much of the tone, responsiveness and character of the original, hand-wired versions of the early days. No wonder builders today still carry on the tradition of the JTM45, and guitarists continue to seek out the pure simplicity and touch response of this tone machine. To celebrate the JTM45, I got together with my Sunday afternoon amp group, after contacting a handful of respected amp builders who sent us their versions of the amp. We fired them all up alongside an original and a reissue JTM45 to take a listen—and to enjoy one of the best amps ever designed.

About the Authors
About 5 years ago, while playing a 9/11 benefit show, I had the good fortune to meet two people who would not only profoundly impact my life with tube amps, but would become lifelong friends. John Rossi and Tony Burns were there that day; Tony, a killer player and a regular on the Tempe/Phoenix music scene, and Johnny, his friend and amp tech, making sure Tony’s amps were running well in 115 degree heat at the outdoor amphitheater. When I saw Tony’s wall of Marshalls next to my backline of Marshalls, it was an instant conversation starter.

We spent time between sets that day discussing the various finer points of our amps and gawking at each other’s rigs. The show went great but my ’67 Super P.A. felt a bit stiff, and wasn’t reacting in the most flattering way. This incident proved to be the catalyst, as Johnny was an underground semi-retired tech and ultra-fanatic Marshall enthusiast, and he had some ideas that he wanted to try out. He invited me over the following Sunday to check out the amp, and to experiment with various preamp and power amp tubes while BBQ-ing and having a beer. Tony was there, and it became clear that we all had a deep respect for these amps; rather than modify them, we wanted to bring them back to their former glory. After five years, and dozens of hacked-up Marshalls coming back from the dead, here we are. Over that time we’ve learned more about these amazing amps than any of us ever anticipated, and we’ve have had a blast in the process. I have no doubt in my mind, based on my readings of the various amp forums, that there are plenty of groups just like us all over the world doing the same thing.

The Lineup
The lineup consisted of our own 1965 original and 1990 reissue heads, two MetroAmp JTM45s (a kit version as well as the GPM 45), a Germino Classic 45, a Wallace Amplification BKW45 and Mojave Ampworks’ new Special Edition Plexi 45 head. After searching through our collection of cabinets, we settled on both an eighties Marshall JCM800 4x12 with blackback 25s, and a Mojave 2x12 cab with 1963-era Celestion Alnico Blues. It may sound strange that there were no pinstripe or basketweave cabs used for the roundup, but that wasn’t for lack of trying. Among all the members of the amp group, we actually have a pinstripe, a basketweave and a variety of Marshall 4x12s, but for some reason we always come back to the early-eighties JCM 800 cab with blackback 25s.

That particular cab has more clarity, tone and authority than any other, and it remains our favorite in the bunch—despite the cool factor of the older cabs. The 2x12 with Blues was a natural choice, as that flavor shares similarities with the mid-sixties Marshall cabs and is also a popular speaker configuration for Bluesbreaker combos. The guitars we used were our standard array of Les Pauls from the ‘70s, ‘80s and 2000s, as well as a newer 2008 Fender Strat and two early-seventies Strats. With everything in the room (it was quite a sight!) we were ready to begin.


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Comments

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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.
Frank M
on 05/24/2009
Question: You say the JTM45 reissue sounds great as long as it's biased hot. What range would you suggest with KT66s? More than 38mA?
Frank M
on 05/24/2009
Well after reading this article, I remembered a used Marshall JTM45 Reissue 1999 model sitting at my local Guitar Center. I recalled playing it a couple times with a Zvex box of rock and thought it sounded nice but no match for my JCM 800 50 watt combo. Against my initial reaction, I decided to go trade my 800 + some other gear and cash to get it. So I took it home and it had amazing low end crunch through 2x12 Celestion G12C Greenbacks as used in the JH Hendrix 45/100 amp. Only thing it had no balls with the existing 5881s. So I popped a set of Valve Art KT66s no screen resistor change or any other alterations necessary and biased them at 36 & 38mA. Shazzam! I'm back on stage with Jimi in 68 and I ain't a kiddin'! Man oh man the thick gooey syrupy low end crunch I've been chasing all my life and thought it was in the speakers. This is a total different animal from every amp I've played including a Dr Z Route 66 based on the JTM45 circuit except it uses an EF86 front end instead of 3 preamp tubes. It was way too clean and needed a pedal to crunch up. Not this baby. I dime it and can nail any early or late Hendrix or Trower. So I changed out one Greenback for a G12H30 anniversary and that took a slight amount of the low end crunch and tightened up the bottom but gave amazing singing sustaining mids out the wazzoo! So now it has the best of both worlds, vintage Jimi with modern but through the mix that will open up a serious can of whoop ass on any Super Reverb, Twin, Bassman or 100 watt modern Marshalls. I just can't get enough of it. While the HW clones sound great on youtube etc, this reissue is everything I've been chasing for 35 years of amp after amp. When you rated the reissue up top, you were spot on because I think I have a very well trained ear and this baby rocks! Don't waste any time on modern amps if you want vintage Hendrix, Clapton, Trower, Free type sounds. The reissue is my choice hands down and I doubt I'll change or mod a single thing about it
gaz
on 05/23/2009
I am wondering if this should be my next Ceriatone, or the HRM (dumble)(hot) clone, I have the Overtone Special and it is my fave. A friend has a JTM45(Bluesbreaker, right?)combo, they are great sounding, loud though, a master volume could wreck the tone I suppose... any way Ceriatone will be my path...
mark lock
on 05/22/2009
i own a ceriatone jtm45 loaded with jj pre amp tubes and kt66 power tubes. the craftmenship of this amp is mind blowing. i play with some of the top players in the st.louis area and they all agree this amp is as sweet as it gets. less than a 1000.00 and shipped perfectly to my front door. i have played most styles of marshalls, fenders, mesa, vox and so forth. the jtm45 in my opinion is the most universal amp in the world, and second to none excepting quatlity pedals.
Anthony
on 05/13/2009
Great article! Very informative. I'd like to know what folks think of the Budda amp.
Frank McLaughlin
on 04/30/2009
Re: major issue with ALL "reissues". I see your point but if you look back on history, the only true lucious tones ever came from those late 60s amps. After that, it's all been garbage tones through particle board cabs till people started realizing they threw the baby out with the bath water. My beef about "reissues" is they're never really a true "reissue". Take the Vox V847 wah where they say "based on the design of the original pedal of the '60s". Well nothing could be further from the truth. if you open up an original you see a bunch of good quality electronic parts hand soldered to a circuit board. The new one is a bunch of surface mounted chips on a green circuit board with a ribbon cable coming out and bears no resemblance at all no does it sound anything like an original to my ears. I think The Metro Amp folks seem to follow through to the closest approximation and the fact that the reviewers thought it sounded the best proves it out so kudos to them and to the others who without tweaking there'd be no innovations. My money would be on Metro though. I would like to hear though about Ceriatone as well from some pros in the know.



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