Marshall Custom JTM Offset – review

I’m a big fan of Fender amps. I own a Fender Hot Rod Deluxe III, which has been my amp of choice for several years. So why did I buy a 1-Watt Marshall Custom JTM Offset? Quite simply, it looks beautiful, sounds glorious and can be cranked at home without blowing the windows out. What’s not to love?

The design of the new half stack is inspired by the early JTM45 Offset that was produced in small numbers by Marshall between late 1962 and 1963. The latest Offset is a limited edition hand-built offering from the Marshall Custom Shop, Bletchley, England.

This single channel 1 Watt amp has been designed to be used at home, in recording studios and at small intimate gigs. It may be limited to one Watt, but it packs an unexpected punch and oozes classic Marshall tone. The fact that it delivers vintage sounding crunch and drive may come as no surprise, but I was unprepared for its gloriously articulate glassy clean tone.

The head is equipped with only two controls, Tone and Loudness, but the two radio-style knobs are all you need to dial in great sounds with the minimum of fuss. With twin ECC83 valves in the preamp and a single ECC82 valve in the power stage, the Custom Offset is configured to work in “push pull”, just like old Marshalls of the ’60s. This amp rewards the expressive guitarist. It feels responsive and dynamic. There are few components to get in the way of the guitar signal, so it sounds big, open, full-bodied and chimey. The new Offset encourages use of the volume control on your guitar to generate everything from bright cleans through to heavy crunch. Stick an overdrive pedal in front of it for all the gain you’ll ever need. If cleans are all you want, just keep the Loudness rolled back. With this amp you can get pretty much any sound by leaving it cranked up all the way – just use the volume pot on your guitar to clean up the tone, the way guitarists used to do it.

Marshal Custom JTM Offset half stack
Marshal Custom JTM Offset half stack (click for larger image)

If using the full 1-Watt output proves too much for the neighbours, you can activate a low power mode via a switch on the back of the head. This drops the amp to 0.1 Watt and lowers the volume considerably, so you can enjoy all the gain this amp has to offer without causing a rumpus.

In general, tube amps get much of their tone from saturating the power section. However, if you run the volume too low on a high wattage amp, you get little saturation. In most environments you just can’t run a powerful amp at full volume without causing damage to your hearing. So what’s the answer? Get a tube amp with a low power output. With an amp using 1-5 Watts it’s very easy to get lush power-tube saturation at low volumes.

The matching closed back cabinet contains a custom voiced 10″ Celestion G10F-15 speaker. The cabinet produces lots of lovely deep low end, so if you didn’t know better you could be forgiven for thinking it contained a 12″. The head and cab together offer tone that is wonderfully rich, pure and vibrant.

Each Offset comes complete with a certificate of authenticity. The Offset is limited to a very short run and will no doubt be prized by collectors. It’s selling quickly, which means that if you go hunting for one on the second hand market expect to pay top dollar.

The trouble with this type of amp is that it gives you a taste for the good stuff, which can be very expensive.  All I need to complete the package is a reverb unit. Now who makes handcrafted analogue spring reverbs? Mmmm.

Video demos courtesy of YouTube

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