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Review – Arkham Abyss Tube Bass Preamp

In the midst of today’s rapid-fire onslaught of newest and greatest products, it’s hard to stand out.

As is often the case, the way a new product cuts through the chatter is not with hyperbole and slick marketing, but when someone you know and trust to have great ears says “man, you gotta hear this thing”.   That’s how I got hip to a tiny shop in Maine called Arkham Sound. And so of course, the unabashed tone hound in me was curious.  When I contacted Micah Smaldone, owner and builder of Arkham, he was kind enough to not only put up with my excessive questions on the phone but send his Abyss preamp in the mail. What arrived was a handsome and robust looking tabletop preamp unit whose feature set and build quality had me interested from the moment I unboxed it.

A little about Arkham Sound:

Micah Smaldone is one of those guys who has been tinkering and experimenting with tube amps and audio equipment since he was a teenager. Originally an acoustic guitarist who in his youth, played in a punk rock band in Boston, Smaldone settled in Maine. “I built a preamp for myself around 10 years ago. I’d been recording an album and was having difficulty with the bass tracks. I cloned a B-15 in a tiny chassis and immediately had the right tone. I felt it worked so well as a standalone unit, I built a few and put them on Reverb or eBay … It took off when someone posted on TalkBass, and I began building them for people. The first one was called the Octling.”

Fast forward to the current state of Arkham Sound.

Micah is busy hand building a line of “Ampeg inspired” preamps for the needs of modern players. I put quotes around “Ampeg inspired” partly because they’re his words, and partly because I find the Abyss to be capable of a wider range of tones and sonic palettes. He may be using Ampeg’s footprint as a starting point, but a couple knob turns jumps the Arkham in to a much broader sonic pool.   The Arkham line consists of 3 preamps, the flagship Zephyr which is a 1u rack preamp which has all of the features of the Abyss, with the addition of a “DI level out” control, a “Pre-out” master volume control, and a Mute switch.  The Bullet pre is the no-frills version of the Arkham line, housed in a slick ammunition case, and features a 2 band EQ with boost switches for “lo”, “mid” and “hi” bands.

When I unboxed the Abyss, I was immediately impressed by its super robust build quality and industrial/military clean and no-nonsense aesthetic.

It is somehow elegant and utilitarian at the same time. All of the knobs have that smooth resistance I love, and the hefty baseball bat switches have a high-quality feel.   The 12ax7 based preamp can be used as a tabletop unit or mounted in a ½ rack with rack ears.

Looking at the feature set, the Abyss has some familiar items and a few unique touches.

The input gain is about what you’d expect. Run it on the low end for clean gain, crank it up above 3 o’clock and you get into overdriven tones.   Running into a power amp with a master volume control, I was able to set it right at the threshold where playing with a light touch was clean and clear, and digging in yielded some very smooth and desirable breakup.    The James Tonestack is essentially a passive Baxandall style tone control circuit and has a very familiar and musical sound to its range.   The treble and bass knob are exceptionally well placed for musicality and versatility.  The hi switch adds a “bright cap” to open up the highs, and the lo switch adds a meaty bump around 80hz, while the mid switch offers a broad bump around 250 Hz, perfect for helping the bass pop through a busy mix.

The last two controls are where things get interesting.  The Abyss features something called a “Range” control.   At first, it’s pretty subtle, but the more I listen to it, the more ingenious I find it. Essentially, it shifts the “tone stack midpoint”, moving the preamps sonic fingerprint up or down to the frequency spectrum to taste, from 150Hz to 1KHz.  I found the sweet spot to be somewhere around 2 o’clock with my rig and according to my tastes, but there is a lot to unpack in that little knob and its relationship to the bass and treble EQ settings, and it’s safe to say that most people will hone in on their happy place pretty quick, and find a great starting point for any additional tone shaping.

The last feature I’ll go over from the front panel is the HPF or “High Pass Filter”.

High pass filters are nothing new, but in the last few years, bass players have started to really get hip to what they do. At their best, they remove subsonic low-frequency rumble which cleans up your stage sound, pockets the low end in a usable way, and reduces the workload on your amp, since it cuts the unnecessary subsonic low frequencies that can hog the power in amplifiers.  I have been using an HPF on my pedalboard for years, and it’s become a “cold dead hands” device for my live rig.   But I digress. Anyways, the HPF on the Arkham is set kind of high on first listen. With a steep cutoff around 150Hz, it does tend to thin out the low end quite a bit.  However, the Arkham seems to be made for a favorite trick of producers and players: using an HPF in combination with bass boost.   By sharply cutting the lows with an HPF and adding them back in with large amounts of EQ (via the bass knob and bass boost switch), you get a less linear and somewhat more energized low end to the sound, which can sound more like a tube power amp being pushed, than a clean tube preamp.  Personally, I preferred the non-HPF’d sound, opting for the leaner, cleaner yet big low end.   But very cool to have these different flavors in one relatively simple box. (Arkham responds:  the cutoff point for the HPF can be set lower if a customer prefers)

The output section of the Abyss is fairly straightforward.

There is a line level ¼” output for connecting to an amplifier, as well as a DI output, which features a “hefty Edcor transformer for full frequency response”.   I had good success plugging the ¼” output into the front end of a bass amp, as well as a power amp input.  The Arkham provides plenty of output and delivers its signature vintage-inspired tone in spades.  I like to think of it as “vintage and then some”

As they always say, the proof is in the pudding.   Great looking, well designed and handsomely outfitted doesn’t really mean much if it doesn’t sound great too.   I took the Abyss to a handful of gigs, including a rock power trio brewery gig, and the Abyss not only delivered, it excelled.  I loved its plump and massive yet firm low end and the full-throated and commanding midrange that sounded like a wall of thickness, but somehow magically didn’t get peaky, bloated or unbalanced.  Sometimes when I hear a piece of gear with a thick low midrange, it can create some buildup around those frequencies resulting in a bloated or boggy low mid profile, but the Arkham seems to be voiced just right, without any of those undesired characteristics.   What’s more, the Range knob allows you to move the tone stacks profile up or down in frequency range, to tailor the Abyss’s luscious sonic footprint for the particular needs of your bass, cabinet, room, or taste.

In addition to my own sense of auditory satisfaction, I was surprised by how other people responded to it.

Band members that I’ve played dozens of gigs with remarked at how great the bass sounded on stage, and asked about what kind of magic box I’m using.  Audience members, known to be painfully oblivious to good bass tone, came up to me asking about my rig and remarking how good the bass sounded in the room.  I take that as a strong indicator, as their obliviousness can be a good reference point for an unbiased opinion.

All in all, it’s easy to see that I was very impressed with the Arkham.

While there is really no shortage of cool pre-amplification and DI options on the market right now, there are always standouts.  I have a short list of tube DI’s/preamps that I think are the bee’s knees, and the Arkham is firmly planted on that small pedestal.  It is easy to use, well built, sounds fantastic and is reasonably priced for what it is and what it does.   At $700, it competes strongly with some of the popular and hip tube preamps du jour.  And the best news?  Arkham is in the process of designing an integrated head, combining all the features and tones of the Abyss with an ultra-high-powered, lightweight, state of the art class D power section.  Also on the bench is an Arkham preamp in pedal format.

For more information on sales and lots of interesting technical info, visit Arkham’s website and follow them on Facebook




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