Diamond Amplification Positron Amp Head Review
November 16, 2010
A class A tube head with simple features and portability that''s both low-watt and loud
|Download Example 1|
Fender Strat Bridge, Diamond Vol 8, Tone 12
|Download Example 2|
Fender Strat Neck, Diamond Vol 11, Tone 1
|Download Example 3|
Gibson SG Neck Pickup, Diamond Vol 1, Tone 1
|All clips played into an Emperor 4x12" loaded with Weber C1625s and recorded with an SM57.|
Diamond Amplification’s founder, Jeff Diamant, recently expanded Diamond’s design capabilities by partnering with boutique amp guru Roy Blankenship of Blankenship Amplification. Blankenship established his reputation as a top builder with his 50-watt, EL34-powered VariPlex (which was modeled after a modified ’68 Marshall plexi) and his FATBoy combo, which is inspired by a late-’50s tweed Fender Deluxe. Blankenship had already designed a smaller version of his 21-watt, class A Leeds21, which he called the Leeds21 Carry-On, and it’s a fair bet that experience informed the design and execution of the Positron.
The Positron is about as streamlined in design as a head can be. It has no protective corners, which can mean increased risk of Tolex damage, but that also adds to the very clean and uninterrupted style of the case. The structural integrity of the box is impressive and feels amazingly solid. The amp rests firmly on quality rubber feet and includes a rugged metal-and-rubber handle. The black Tolex (burgundy snakeskin is also an option) is as smooth and seamless as any amp I’ve ever seen, and the backplate fits perfectly flush with a back grate that enables a view of the amp’s interior. Inside, two EL84s in the power-amp section form the backbone of the Positron’s handwired, all-tube circuit, which also features three 12AX7s in the preamp and a 6AC4 rectifier. In short, the Positron is a really well-built amp—though the most brilliant aspect of its design may be that you can fit all this tube-driven goodness inside something the size of carry-on luggage.
Evaluating the Positron was a matter of hooking up my Gibson SG and Fender Stratocaster and routing the Positron’s signal through an Emperor 4x12 loaded with Weber C1265s and an Avatar 2x12 with Celestion Vintage 30s.
The Positron’s front-panel controls are dead simple: There’s a power switch, standby switch, Tone knob, Volume knob, Input jack, and just about the brightest red jewel light on the planet—that’s it. Starting with the Tone at noon and the Volume low, the amp jumped to life with a sharp, brilliant, Vox-like clean tone—especially with my SG’s bridge pickup. AC30 fans should definitely give this amp a test run.
Switching to the neck pickup produced a predictable boost in the amp’s low mids, which the Positron handled beautifully, retaining a fully dynamic clean tone that didn’t break up too easily at low volume. The amp is really expressive and present in clean mode, and plenty loud too. But the amp does not stay clean for long. Bringing the Volume up to just 10 o’clock produced a fantastic, bluesy breakup that responds, like any good tube amp, to even the most delicate fingering. And what I quickly discovered was that this amp could have easily included just a single volume knob. With most amps, I find myself searching for a slightly brighter sound, but from sparkling clean to raunchy overdrive, the folks at Diamond Amplification have obviously taken the time to make sure this amp is voiced perfectly right at noon. The Tone knob is still useful and enables subtle brightening or darkening effects, but it does not deviate much from what Diamond deemed the ideal tone.
With my Fender Stratocaster and the Positron wired to the Emperor 4x12, I rolled the Volume up to noon and let the Strat’s bridge single-coil kick out the twang with a startling volume and dynamic punch. Because of the non-Master volume architecture, I was also to dictate an array of responses quite readily by using the guitar’s Volume knob. For kicks, I dimed the amp’s Volume and strummed power chords, which filled the room with thunderous rock ’n’ roll tones that were similar to an AC30’s, but with a bottom end more like an early Marshall (a quality that was no doubt enhanced by the 4x12 cabinet). Switching to the Strat’s neck pickup kicked up the low-end content yet again, and the amp responded with a smooth, creamy overdrive.
In search of more classic rock tones, I routed the Positron to the Celestion Vintage 30-loaded 2x12 and plugged in my Gibson SG again. The hotter output from the humbuckers drove the Positron into overdrive land, with the preamp emitting traces of sizzling distortion. This is as close to a Marshall sound as I’ve ever heard from a class A amp. Sustained lead notes rang out with musical feedback. Throughout all settings, the amp’s dynamics remained intact, and I had to think that the Positron would be an invaluable amp in the studio.
Tone that hearkens to ’60s, class A, non- Master-volume British amps has been a sound ideal among amp freaks for years. Now, Diamond Amplification’s Positron allows you to access those beautiful vintage Vox and Marshall tones in a moderately powered, portable package that sacrifices nothing but the heft of those icons. The two-knob control setup makes it quick and easy to tap in to the tonal magic, and the compact package means you can take it anywhere, provided there’s a cab waiting for you at your end destination. For class A fans on the run, the Positron is an ingenious little amp of surprising capability.
you crave a handwired, compact, no-nonsense class A tube head that’s loud.
one channel isn’t enough.
Street $1499 - Diamond Amplification - diamondamplification.com