All right, I’m a sucker for rarity.  As a musician in pursuit of uniqueness, I always get tempted into checking out rare and unique gear — of course, the underlying desire is to find that elusive piece that helps you define your unusual, personal sound. From Ty Tabor’s Strat Elite to Brian May’s Red Special or Buddy Miller’s Wandre Davoli guitars.

Well, this is a review of a rare pedal called Diamond J-Drive TR.  100 of these were made in 2006, and since then the company has been making J-Drive Mk3, which I understand is just like TR except that it doesn’t feature the dual-function part of the boost side.  It’s a simple 4-knobber with boost going into an overdrive, but don’t let its simple user interface fool you — there are a couple of noteworthy twists here.  I don’t know if it really sounds unique and twisted enough to make me or anybody else stand out, but it certainly has a little something to make it stand out of the crowded overdrive market.

Features

So, Drive and Volume are self explanatory.  This 3-knob overdrive side doesn’t have a tone knob, though, instead it has Warmth.  What does it do?  Several things at once — turning it up makes the sound louder, with mellowing of the top end and beefing up of lower mids.  Warmth, indeed.  The knob has a huge range and its effect is not subtle.   There is a Bright switch also, though its impact is subtler than the Warmth knob.

On the boost side, it has a single Gain knob that sets the amount of boost, but the TR-only trick is that you can pull this knob up. In the normal mode it is a general-purpose clean boost, but pulling it up makes it a scratchy, gnarly germanium treble boost.   You can read more technical details about this pedal on their archive page.

Sounds

Thanks to its powerful Warmth control, J-Drive manages to sport much more range than what you’d expect from a typical overdrive.  When the Warmth is turned fully counter-clockwise, it has a cutting edge, perfect for busy strumming rhythm guitar.  It’s very dynamic, though its response is still unmistakably that of a solid-state pedal, not spongy and organic like a tube amp.  All the way on the other side of the Warmth knob, it is woolly and fat, great for single-note playing and has a wonderful vocal quality to it, without sounding nasal like a cocked wah.  The Drive knob has a pretty healthy range, can go from barely noticeable to raunchy classic rock dirt.  So between the Drive and Warmth, you should be able to find a sound that works for pretty much anyone.  My personal opinion is that a pre-gain bass roll-off and post-gain treble cut (think Paul Cochrane’s Timmy) is the most versatile EQ configuration for a dirt pedal — but this one-knob Warmth control is really challenging that notion.  It’s simple in a very powerful way.

The bright switch, as I mentioned, is on the subtle side — it feels more like a slight low-end cut than a boost on the treble side.  Being a single-coil player, I don’t see any need for it on the left half of the Warmth range where the tone is plenty defined already.  It may be useful when you set the Warmth high on a darker sounding guitar.  But then, this pedal features a treble boost, too.

The boost can add quite a bit of gain and saturation to the already healthy range of overdrive.  The treble boost does add more coloration and definition — it doesn’t strike me as terribly peaky on the treble, like some treble boosters do, but the unmistakable kerrang of an old-school treble booster character gets stamped on the sound.

My Verdict

So between the Gain, Warmth and two kinds of boost, this pedal can achieve a surprising range of tones for a simple 4-knob pedal.  I’d thought I would miss a tone control or bass knob but really — the balance Diamond strikes between simplicity and flexibility is quite admirable.  So many gear ends up clouding the user interface with too many knobs in the name of flexibility, only to confound the users and have them endlessly turning knobs.  This one is intuitive and instantly tunable to your needs.

But, like all overdrive pedals, this one does have some limits.  Though responsive and dynamic, this is not an amp-in-a-box type pedal.  It’s not ashamed to sound and behave like an overdrive pedal, with its boxy, constrained feel.  So if you’re looking for a more tube amp-like organic dynamic response, this may not fit the bill.  There is absolutely nothing wrong with an overdrive pedal being unabashedly that — many players swear by classic Boss and Ibanez units.  J-Drive is more responsive than a typical mass-manufactured overdrive pedal, but there’s no mistaking that it’s still a pedal.

I realize the TR version is hard to come by because of the number of units being produced, but J-Drive Mk3 looks pretty much the same pedal sans the germanium treble boost, at least on paper — so I’m hoping that my review will help inform your decision to check out J-Drive Mk3.  I think the balancing feat of simplicity vs. flexibility Diamond achieved with this pedal is pretty awesome, so if you like the idea of a flexible overdrive but are turned off by the idea of many knobs, this one may hit the sweet spot.