Not long ago I was searching high and low for a Marshall JMP from the ’70s. These aren’t terribly difficult to find—they pop up from time to time online, and even at big-chain guitar stores with used instrument sections. The problem is that the JMP is a longtime favorite of amp modders. Many dubious modifications can lurk beneath the surface of these amps. I've heard horror stories about mismatched transformers, “special” caps, and midrange boosts. Not wanting to gamble on a potential lemon, I shifted my search to newer amplifiers built for vintage tastes.
That search led to the doorstep of Dr. Z, a company with a reputation for vintage-sounding circuits that always seem to deliver something extra. Their latest is the Antidote, a 45-watt, two-voice head that delivers soaring KT66-driven tones reminiscent of everything from early JTM45s to those ’70s JMPs I’d been lusting after—all from a beautifully uncluttered and easy-to-operate six-knob control set.
Channel Linking without the Fuss
Like Dr. Z’s Remedy amp, the Antidote achieves much of its versatility via creatively configured volume controls. Decades ago some inspired tone seeker found you could link two input channels on Marshall plexis and Hiwatts to blend the high and normal inputs. Dr. Z modifies the equation (and eliminates the need for that little 1/4" cable) by offering one input and utilizing two volume controls to mix channels. The high input knob adds top-end shine, while the normal channel has a darker personality.
The Antidote’s power section uses an ultra-linear output transformer and runs two Genalex Gold Lion KT66 power tubes (reissues of the clear glass originals). Purists may scoff at anything short of new-old-stock, gray-glass Genalex KT66s, but the reissues are powerful as hell and don’t cost a fortune. The preamp section utilizes three 12AX7s, and there’s a 5AR4 rectifier.
Another important feature is the front panel’s modern/vintage toggle. The vintage voicing tends toward tweed Fender Bassman rumble—fat with ample low end. Flipping to the modern setting focuses the midrange, enabling everything from Blue Cheer-style rage to more ’70s-style flavors. You control both voicings via a single tone section (3-band EQ plus a presence knob). You can also use a footswitch to bypass the EQ section for savagely loud high-gain lead sounds. There are separate outputs for 4 , 8 , and 16 cabs.
Like all Dr. Z amplifiers I’ve played, the Antidote is expertly crafted. It’s handwired at the company’s home base in Cleveland, Ohio, and my review model is covered in blonde vinyl. (Black and red are also available.) The 27-pound head is constructed from 1 1/4" birch. Its corners are reinforced with metal brackets, and it rests on four extra-large rubber feet. In addition to a jagged metal “Z” nameplate, this model is emblazoned with a serpent-entwined caduceus, a clever play on the amp’s medical-sounding name and an elegant match for the Antidote’s clean, uncomplicated aesthetic.The Volume Man Cometh
First off, this thing is “holy $#!t” loud. If you seek bedroom levels with serious crunch, forget it. With no master volume, you need to crank the Antidote to get its 45 watts cookin’. That said, lower volume levels are more than suitable for clean tones, though you’ll still need to give the amp a fair bit of gas to get the fullest low-end tones. Pegging the normal volume at 10 o’clock with the high volume around 8 o’clock produces a clean-ish Marshall-type tone, albeit on the darker end of the spectrum.
The KT66 power tubes are often associated with Clapton’s Model 1962 “Bluesbreaker” sound, and the Antidote mimics that classic Marshall combo well. The picking response is exemplary—punchy with a resonant, bell-like attack that gets dirtier the harder you dig in. Keeping the toggle in vintage mode opens up room to explore these sonic regions, and pairing the Antidote with humbuckers helps nail those Clapton tones. Switching to a Fender Jaguar, I found myself rolling back the amp’s presence to accommodate the brighter single-coils. Setting both volume controls to noon summons tones akin to a driven JTM45 or Bassman. Expect crunchy clarity with well-defined bass heft.
Flipping the character switch to modern provides a significant mid boost that usually requires some EQ tweaking for both humbuckers and single-coils. The amp’s overdrive capabilities blossom in this setting, where you get an extra spoonful of output.
Paired with humbuckers, the Antidote is a heart-stopping, Thin Lizzy-style hard-rock machine, rich with sustain and natural compression. Dirtier settings also yield smooth, singing sustain, but remain airy in the upper-mid frequencies, with an elastic picking response.
Both closed and open-back cabs work great with the Antidote, though I preferred the gloriously sharp snap of a 4x12 paired with the KT66s. Adding pedals to the mix showcases the Antidote’s clarity. Fuzz pedals are especially effective—even the chainsaw buzz of an EarthQuaker Devices Hoof Fuzz retains its unhinged but harmonically rich voice.
Dr. Z amps aren’t exactly cheap, but they’re beautifully built. Take care of the Antidote, and it’ll probably take care of you for a very long time. This 45-watter isn’t for high-gain freaks, but it delivers aggressive hard-rock tones and enough volume to sail over the loudest band. It will capture the hearts of vintage-Marshall and tweed-Bassman lovers. It rewards old-school overdrive methods—namely, working your guitar’s volume knob. The prismatic cleans turn on a dirty dime if you give it gas, with humbuckers providing a heavier crunch at lower volumes. If vintage Marshall tones have eluded you, or if you like the idea of JTM tones plus a little something extra, Dr. Z does indeed have the Antidote.