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TWS Bass Boy

All-Tube. For modern Bass Players. Finally.


"Why isn't there an all-tube bass amp which suits the demands of studios and smaller venues of our days?"

This is one of the most frequently asked questions that we have been asked since Tube WorkShop was founded.


We cannot answer that question, but we can say: It's here now. The Tube WorkShop BassBoy!


Even if our BassBoy is a completely new development, it is inspired by the legendary Ampeg B-15. This studio icon shaped the bass sounds of of a whole era. With a power amp switch between 30W Cathode Bias (like the 60s models) or the 50W in Class A/B mode of the 70s models of the B-15, the BassBoy does justice to both decades.


The legendary Baxandall tone control, specially developed for bass applications, has been completely revised and, with the new "Character" control, offers complex access to the important mid-range spectrum. This allows the BassBoy to switch effortlessly between traditional (rather aggressive) bass sounds and modern, tidy sounds.


guitar 09/2023

"So why aren't there "small" tube amps for bass? This is a question that worries me and no doubt many other bassists as well. Mario Gebhardt, the mastermind behind Tube WorkShop, has taken our cue and designed the BassBoy, a 50-watt tube amp for bass, which is intended to close this gap on the market.​ [...].  The BassBoy is (once again) a heavy hit from TubeWorkShop. With its compact format , it covers all needs of the High-End community and fills a real gap in the market." 


Guitar & Bass 01/2024

"There are other candidates for pure performance and analytically clear playback, that should be clear to everyone who is looking for good tube sound. There is plenty of it here and in a quality and flexibility that is second to none. Even at low volumes it has Tone is addictive, when turned up the desired saturation comes into play in a pleasant way. The easy-to-use preamplifier offers a cornucopia of sounds; everything I fed to the combination was not only reproduced with all the advantages of good tube sounds, but could also be refined with a strong character." Here you can read the Full Article ...



handmade in Germany.

Every BassBoy is handcrafted in Leingarten (D) and wired point-to-point with the shortest signal paths. All connections are soldered (no connectors) to permanently prevent loose contacts and contact resistance.


The massive (2mm thick) aluminum chassis carries only hand-picked premium components as well as the highest quality transformers and an "over-designed" power supply for maximum durability. Only the best is good enough for us.

The mechanical installation of all components is completely decoupled from the electrical connections. Jacks, pots and tube bases do not exert any forces on the electrical connections that could lead to broken solder joints over time.


An extremely robust housing made of solid 18mm pine multiplex gives the BassBoy a high level of roadworthiness and at the same time is very easy to transport thanks to the generous carrying handle. Of course, the housing is handmade in Germany.


guitar 09/2023

"Mario doesn't skimp when it comes to craftsmanship. For the price asked, you should be able to expect that, but the expectation is undoubtedly fulfilled!"


Guitar & Bass 01/2024

"I don't know how you feel, but looking at a circuit that has been accurately built by hand with the best components and soldered point-to-point makes me feel happy. You look for circuit boards in vain, but the components, cable routing and workmanship are leave no doubt about the claim to deliver the finest here. This looks extremely promising and is also service-friendly."

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Tone Control

3 knobs. From "modern" to "vintage".

Normally, bass players are used  to be "left alone" with a flood of controls in order to somehow tinker heir "desired sound". At TWS, we wanted it to be more simple and more practical... with fewer controls!


Based on the classic Baxandall tone control, which works very efficiently on the bass and treble range, we invented the "Character" control, which controls the important mid-range in a multi-layered manner".


With the character controller you can continuously fade back and forth between a more "modern" and a "vintage-oriented" sound. "Modern" brings a very contoured and tidy bass sound, which is also ideal for slapping. "Vintage" results in a dense and assertive midrange, as we know it from countless recordings.


The "Character" control does much more than just boost or cut a specific center frequency. Rather, both the center frequency, the bandwidth and the boost/cut are continuously altered over the entire control range.


We can proudly say that this tone control is pretty unique!



"When it comes to tone control, we're not simply dealing with a classic 3-band EQ. As with the Ampeg model, the BassBoy has a Baxandall tone control. [...] But what's the deal with the controller in the middle? Instead of "Mids" it says "Character" and in fact Mario has incorporated a technically complex but very simple control, that determines the tonal orientation of the amplifier. On the left side you counteract a modern, tidy bass sound that tends to be clear, while the right side is dedicated to growling, dedicated vintage sounds."


Guitar & Bass 01/2024

"Gain and master regulate the input and output volume, and there is also a three-band tone control. It can be that simple! But it's not quite that simple. [...] Wedt the tone controls make it easy to emphasize the character even more or to adapt the sound to the room and personal taste. Even larger sound changes are possible. This is where the mid control shines, as it supports an astonishing slap tone when turned all the way to the left, while at the other end it brings the mids into focus across a broad spectrum while at the same time reducing the highs quite a bit. The complexity with which it is regulated here - simultaneous processing of frequency, filter quality, boosting, cutting - can be heard in a complex sound image; it couldn't be simpler and more uncomplicated to operate."

Preamp & Ultra High

Full controll over distorted sounds.

The TWS BassBoy was specially developed to deliver the coveted distorted tube bass sounds.


This is achieved through a finely tuned combination of the preamp control (= gain) and the "Ultra High" function, which can be activated by pulling the control. "Ultra-High" is not a gain boost, but a finely tuned treble boost. Our circuit is different from the original "Ultra-High" in the Ampeg B-15, but for nostalgic reasons we kept the name,

In addition to the fact that the "Ultra High" function can bring even very dull-sounding basses back to life, this function is the "weapon of choice" when playing with the plectrum and with the BassBoy in the complex world who wants to immerse themselves in distorted tube bass sounds. Ultra-high "On", character in the direction of "vintage", reduce bass and treble a little - and Motörhead Rules.


Have fun with it!


guitar 09/2023

"The degree of distortion can be finely controlled via the Preamp-Knob. The spectrum ranges from a clean, but always warm sound, to a wonderfully dynamic crunch sound that, depending on intensity of playing, sounds either clean or beautifully grumpy. Up to a rough tube distortion sound that makes the faces of Black Sabbath and Motörhead fans smile. With a pull on the preamp control, the "ultra bright function" is activated, which gives the signal additional clarity and highs."


Guitar & Bass 01/2024

"With maximum mids on the amp it gets the Spector Ethos imposes an almost classic, round sound with plenty of growl. The treble control on the amp is only slightly effective even when turned up to full capacity - but there is also the bright switch on the volume control, and that brings the brilliance back in one fell swoop. It has just as big an effect on distorted sounds. They almost come naturally, because despite all the flexibility of the preamplifier, the power of the power amplifier is limited, which is part of the fun. With higher gain in the preamp or higher load on the power amp, a rich growl is achieved, which can be pushed up to tube-like distortion with even more gain and the post-phase inverter master extended."


Guitar & Bass 01/2024

"TWS sees the best way to record the amp live or in the studio by using a microphone, but the DI standard should still not be missing and should then be as good as possible, namely transformer balanced with the best transformer. Groundlift takes care of any hum loops."

DI out

Transformer symmetrical. What else?

Every good bass amp needs a balanced XLR DI-out.


Even if miking the bass speaker is the variant with the most character, the XLR DI-Out has established itself as a fixed connection standard for bass amps.


Of course it is also available with the TWS BassBoy. And of course we have installed the highest quality variant for you. This is transformer-symmetrical with a first-class transformer and of course has a GND lift switch to prevent ground loops.

The DI-Out on the TWS BassBoy is absolutely “pure” and not frequency-corrected to give you maximum freedom when processing the signal. Especially if the BassBoy is run with distortion, we recommend using an IR-Loader with your favorite cab sims as the speaker sound has a very big influence here.

Or you can just do it the classic way: Microphone in front of the speaker, and "What you hear is what you get!"


Master & Power

Contemporary, with options from the 60's and 70's.

Gone are the days when you had to cover the whole concert hall with 300W tube amps and huge 8x10 speaker cabinets.


Today, we are happy to leave applications that require "pure power" to the well-assorted field of Class-D amplifiers. 


In our opinion, 50 "tube watts" represent the "sweet spot" in order to have sufficient headroom in most applications and to be able to fully enjoy the coveted dynamic tube sound.


In order to perfectly set this to your personal needs, the TWS BassBoy has a PPIMV master volume that controls the volume at the latest possible point (i.e. directly before the power amp) and only minimally influences the overall sound of the amp.


But that's not enough for us.

With the 50W/30 switch on the back of the BassBoy, the behavior of the power amp can be switched between the early B-15's with "Cathode Bias" (approx. 30W) and the later B-15's (with approx. 50W Class A/B and toggle "Fixed Bias").


The volume differences are rather marginal. With a "fully cranked" TWS BassBoy, however when fully cranking the amp, you will appreciate the differences, where the 30W Cathode Biased option reaches saturation much earlier than the more stable Class A/B variant from the 70s.


Guitar & Bass 01/2024

"The bias switch selects between two methods of determining the operating point of the power amplifier tubes, which result in different output lines. Differences that the Ampeg models also had at certain times in their history. [...] The response is in 30-watt mode "sweeter", here the power amplifier is operated with cathode bias like the B-15 flip tops until the mid-60s, the mode with fixed bias, borrowed from the 70s B-15, brings the power to 50 watts and remains more stable. "


Technical Specs

and specifics.

  • Handcrafted in Germany

  • Shortest signal paths. Best components. No connectors.

  • 50W Class A/B / 30W Cathode Bias, switchable

  • 2x 6L6 power tubes

  • 1x 6SL7 preamp tube

  • 1x 6SL7 Paraphase Phase Inverter

  • GZ34 rectifier tube

  • Post Phase Inverter Master Volume (PPIMV)

  • Preamp (gain) control with "Ultra-Bright" function

  • 3-band tone control with bass, treble and character controls

  • 4/8/16 ohm speaker impedance selector switch

  • Transformer-balanced DI-Out (XLR) with GND-Lift switch

  • Dimensions: WxHxD = 530 x 260 x 260 mm

  • Weight: 14 kg


TWS BassBoy top: RRP €3,299


Or contact us personally:


You can also get all of our products from:

Thomann_Logo_with claim.png

guitar 09/2023

"The price asked is definitely proud, but absolutely justified in view of what is on offer. Who can afford it, and is looking for the bass amp for a "lifetime", you should take a closer look and listen to the BassBoy."


Guitar & Bass 01/2024

"You don't have to pay a lot of money for this, but the quality in every respect justifies it for me, especially since there are few alternatives. If you have the opportunity, definitely play!”

TWS 1x12 Bass Cab

"Small" speakers can sound "Big"...

To match the TWS-BassBoy, we decided on a compact but fully-fledged bass speaker with 1x12 full-range equipment.


An additional tweeter was deliberately omitted in order to achieve a lively but never cool or sterile sounding treble range in combination with the BassBoy. 


The decisive factor was the construction made of 15 mm birch multiplex in a closed housing with a well-coordinated bass reflex opening on the front. This creates a consistent sound across all frequency ranges. The TWS 1x12 bass box is both balanced and very powerful with the smallest possible dimensions.

  • Handbuilt in Germany

  • Standard equipment: 1x12" Eminence Kappa-12A speaker

  • Load capacity: 450 W

  • Impedance: 8 ohms

  • Housing and baffle made of 15 mm birch multiplex

  • Closed housing with bass reflex opening on the front

  • Generous carrying handle

  • Dimensions (W x H x D): 595 x 400 x 300 mm

  • Weight: 15.5kg

  • Cover: Black Tolex

  • Front covering: Black/Silver



TWS 1x12 Bass Cab: RRP €1,099

Available from November 2023

Or contact us personally:


You can also get all of our products from:

Thomann_Logo_with claim.png

guitar 09/2023

"The TWS 1x12 bass cab has a practical format, a birch multiplex housing and is equipped with a 12" Eminence Kappa 12A speaker. The cab reacts very directly, reproduces the warm amp sound excellently and is even not a heavyweight at 15.5 kilograms. If you want it even lighter, you can also have your TWS cab equipped with a Jensen Bass Smooth Neodymium upon request."


Guitar & Bass 01/2024

"The associated box keeps up with the top in terms of appearance and quality. [...]. The Eminence Kappa-12A twelve-inch speaker is very modern and can be loaded with a maximum of 450 watts. The Jensen Bass Smooth is optionally available, thanks to neodymium lighter, yet smoother in tone. [...]


Not only does the box go down far enough to convincingly play the low B string, but also the ultra-modern sound design of an Spectors is superbly hit and strengthened."


Power or Lightweight?

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Our Standard: Eminence Kappa-12A

A legend among 12'' bass speakers. Heavily built, high efficiency. Extremely "direct" and very balanced. This speaker literally "jumps" at you and sonically "pushes" you in every situation. Within the best speakers you can get...

Lightweight Alternative: Jensen Bass Smooth 12

- Free of charge -

The Jensen Bass Smooth offers a very clear and differentiated sound with a weight of only 2.5 kg.

We recommend this speaker for all applications where low weight is more important than maximum sound pressure and power.

Tailored TWS Covers

keep the fun going...

TWS Protective Cases Top & Box

Of course, the best thing for your darling would be a flight case. But that's where things get big and difficult. And when you're not on a world tour, a good protective case is the perfect and affordable everyday companion.

  • Handmade in Germany

  • Custom made to fit the TWS BssBoy

  • Tailored to fit the TWS 1x12 bass box

  • Perfectly sewn imitation leather protective cover in leather look with sewn-on TWS logo

  • The protective cover is padded and splash-proof. It protects against knocks during transport and also against fading (UV protection) and dust.

  • Thanks to the neatly incorporated handle recesses, the amp and box can still be transported without any problems.

Price BassBoy Top protective cover: 69,-€

Price TWS 1x12 Bass Cab protective cover: 79,-€

Sound Samples

let's stop talking... just listen.

Pictures, pictures, pictures

Tell more than 1000 words.

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