Darkglass Microtubes B7K Ultra Bass Preamp Overdrive Review

Based in Finland, Darkglass Electronics is well-known for their high-quality, versatile electric bass gear. Their mission is simple – to help bass players of every genre take their tone to the next level. And from my time with a few pieces of their gear, I think it’s safe to say they have succeeded. Today, we take a closer look at one of their more popular offerings — the Microtubes B7K Ultra bass preamp. Based on the already great B7K, this bass preamp looks to kick things up a few notches.

The Features Of The Darkglass B7K Ultra

Compared to the B7K, the Ultra version adds a second footswitch (to turn the drive and preamp circuits on and off) and toggles for more control of both the low-mid and hi-mid frequencies, with three separate settings for each. Overall, these additions add a ton of versatility to the package. Including these new features, the Ultra boasts a total of 8 separate knobs, 4 three-way toggles and two and foot switches. If anything can be said at first glance, it’s that it’s not lacking in control options. And while this might make the B7K Ultra a bit intimidating at first glance, it all comes into place once you break everything down.

Darkglass Microtubes B7K Ultra Preamp OD @ $389.95

The Microtubes B7K Ultra features all the versatility and sonic possibilities its predecessor is known for plus amazing features: (1) A dedicated Footswitch to engage the overdrive section independently. (2) A Master volume to control the overall unit level. (3) Three-way toggle switches for each mid control, with a total of 6 different mid frequencies at your disposal the B7K Ultra allows you to create and tailor your tone to perfection: From crisp, punchy clean preamp to obliterating high gain distortion, and everything in between. The B7K is a universal tone-crafting machine.

Starting with the top four knobs and two toggles, you have the Ultra’s overdrive circuit. The Drive knob allows you to set the desired amount of gain while the Level sets the effect’s volume. Blend handles the amount of wet signal you want to be mixed in with the dry signal and Master controls the overall output level. Moving on to the toggles, Attack impacts the high-end frequencies of the wet signal which can be set to either flat, boost, or cut. Grunt, meanwhile, features the same three options only if affects the low-end.

The next set of four knobs and switches houses the pedal’s 4-Band EQ/preamp section, with settings for Bass, Low-Mids, Hi-Mids, and Treble. Each works exactly as you would expect, which is definitely not a bad thing. As for the two toggles, they allow you to choose between 250 Hz, 500 Hz, and 1 kHz for the Low-Mids and 750 Hz, 1.5 kHz, and 3 kHz for the Hi-Mids.

Then there are the two footswitches labeled Distortion and Bypass, each of which can be engaged independently. For example, you can switch the preamp section off and use the Ultra as a dedicated bass OD. You can also simply use it as a preamp DI to craft your clean bass tone. Of course, you can also use them together.

And finally, the B7K Ultra also features a Ground Lift push toggle, XLR DI output and in/our signal jacks.

The B7K Ultra In Action

If there’s one word that could be used to describe the B7K Ultra it would be “Versatile.” If you removed the preamp/DI component completely, the B7K Ultra would be one of the best bass overdrive pedals out there. It can easily go from a slight grown to full-on distortion — or anything in between — with a twist of a knob.

Conversely, the preamp section is no slouch either. Need a touch more brightness? How about something that can cut through the mix without being too overwhelming? Something with a good amount of thump without being too boomy? It’s all in there and just a twist of a knob of a flick of a switch away.

Combine the two and add in the extra features like the ability to use either section independently, the DI output and ground control and you easily have one of the most versatile and powerful bass amps around. And while the price tag might seem a little steep, you’re essentially getting a great bass OD, preamp, and DI box all in one.

While there is definitely a lot to like with the B7K Ultra, it certainly has some negative quirks. First off, it’s pretty big for a pedal. Yes, the amount of control and versatility more than makes up for its size but pedalboard real estate is a precious commodity and the Ultra will easily take the spot of two or three pedals. And then there are the switch toggles. Even though it’s obvious they were made to be a set-and-forget type of control, there are definitely instances where I would have loved to be able to switch between some of the settings on the fly. Overall, nothing too serious.

Final Thoughts …

One the most versatile bass stompboxes we’ve seen, the Microtubes B7K Ultra is more than just a simple overdrive pedal. Sure, it’s in there, but it also works just as well as a bass preamp and DI combo, making this piece of gear a triple threat bass effects pedal and a worthy addition to the Darkglass lineup. And with new features like dedicated overdrive toggle footswitch, a Master volume control for the overall level and three-way toggle switches for each mid control, you have a powerful device that allows you to meticulously craft your tone with plenty of precision. Whether you’re looking for a punchy yet clean bass tone or a biting high gain sound with plenty of growls – not to mention anything in between – the B7K Ultra can deliver.