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Wednesday, December 13, 2023

Compactron : What is it and who is it for ?


This year I introduced a whole new product line of electronics which I called Compactron. I thought it would be a good idea to explain the philosophy and idea behind this new line a bit in detail.

While my existing line up of electronics remains quite popular among music lovers, there are many for whom it does not fit for various reasons. One comment I receive a lot is the sheer size which comes with the external power supplies. Some people just do not want to have so many chassis which can be up to 8 for a combination of phono, line and power amps. This is most often a remark from the better half of my customers. Next point is the look. While many, including myself love to see a landscape of tubes, capacitors and transformers on top of the chassis, some people prefer a simpler look. Next is flexibility on the phono stage: I get many requests for the inclusion of multiple phono inputs and to support both MM and MC. Also the possibility to adjust input impedance and capacitance is often wanted.

Of course in order to pack a complete preamp including phono section and power supply and additional features into a single housing, the design needs to be somewhat simplified and I needed to let go of transformer coupling (at least partly), LCR RIAA EQ and the use of directly heated tubes. Beginning of this year I built a first prototype to prove that I can fit everything into a single chassis and inclusion of the power supply will not introduce any problems with hum.

The first prototype was finished in February. The phono section was completely done in RC coupled fashion and with passive split RC RIAA EQ. For the line section I wanted to keep transformer output coupling and transformer volume control. Also tube rectified high voltage and choke filtered supplies remained a must have. The prototype worked and sounded nicely without noise but it turned out bigger than I would have wanted with more than 60cm depth. So further compaction was necessary.

In my tube of the month series of articles I presented many so called Compactron tubes. And I choose such tubes for the prototype. The 6FM7, 6FY7 and 6BE3 rectifiers. I always wanted to make more use of Compactron tubes, so the decision to exclusively use them for the new product series was set. Hence the naming of the entire product line which also reflects the compactness of the housings. A bit of background about Compactron tubes can be read in the 6GE5 tube of the month post

For the chassis of the new series I needed to find a new metal supplier. I wanted the faceplates with brushed surface and exposed sides. After getting samples from different suppliers I realised that not everybody can do that in good quality. But I was lucky to find the right partner for supplying the chassis material. Better component layout enabled me to get the size down to a foot print of 434 by 434 mm and all within 100mm height. The first final version was a full function preamplifier similar to the prototype. It had 4 phono inputs (2 MM and 2 MC), balanced and single ended line inputs.

Transformer coupled line out, transformer volume control and as a special feature a gain switch which can set the phono stage gain in 4 steps was added to the back.

Soon afterwards the first orders for Compactron gear came in. A line stage was first and also the first to try different color anodisation.

Next was a phono stage with adjustable EQ curves for historic records. This time with an orange faceplate. Having a metal supplier at hand who can do such quality metal work I decided to also offer my existing products in a similar chassis, with the 10Y linestage being the first to receive this housing. D3a phono and also power amps will follow.

With all these new developments in the product line up came the decision to exhibit at next years High End show again, after a 3 year break. That means a complete lineup has to be ready and the next one was a Digital to Analog Converter with volume control. 

The DAC was the first Compactron unit which received metal side panels as an alternative to wood.

And the next addition to the line up was a Stereo Power Amplifier.

Together with the DAC this amp is all you need if you only want to use digital sources.

All Compactron chassis are stackable.

The round recessed circles on the top plates can hold stainless steel discs which support the spiky feet of equipment placed on top.

More Compactron gear coming up with another full function preamp next.

Also a pair of mono power amps almost finished.

5 more different pieces coming until end of January: An integrated amplifier, more DACs, a stand alone phono and a line stage. All will come in different colors as show pieces for the High End show.

Now that I explained a bit about the history and motivation of this series of products, who is it for? Firstly of course for those who want something more compact and those who are looking for more flexibility in the preamplifier. However compactness can be relative. The chassis are still quite substantial with the width of 434mm and they are also quite heavy due to the liberal use of metal with 25kg and more depending on which unit.

In the recent years 'tube rolling' became more and more popular and seems to be a big trend in the moment. On the other hand I heard from many people who would be interested in tube gear that they are scared off by this because they have the impression that tubes need to be constantly changed and one needs to search through many different tubes to find the right set for their taste.

Tube rolling is not needed with these. As far as I know Compactron tubes have mostly been produced by General Electric and other companies simply sourced their Compactrons from GE and relabelled them. So no need to hunt for rare brands. Compactron tubes were one of the very last developments in tube technology to show the capabilities against the transistor. Vacuum tube technology was very matured by then and Compactrons were mostly produced for TV sets in the millions. That led to very rugged and reliable tubes. I have an amp with Compactrons running daily since well over 10 years and the first set of tubes. They will probably run for another decacde.

So this series of products is for the music lover who does not want to fiddle around with his gear. Who just wants to plug it in and enjoy music. And enjoy you can with them. I am very happy with the sound of the first units I built and they all sound very smooth with a lot of PRaT (pace, rhythm and timing), dynamics and a beautiful tone.

It is also for people who like the simplified aesthetics of the housings. Without unnecessary gimmicks. Reduced to plain functionality in the tradition of great HiFi gear from the 80ies which inspired this design. Also inside no nonsense, no PCBs, all hand wired for sonic bliss. All Compactron gear has these characteristics in common:

- Each unit comes in a single chassis (power supply integrated)

- All Compactron gear has tube rectified high voltage

- All power supplies are choke input filtered (including DC heaters in phono and DC voltages for DACs)

- No electrolytic capacitors in the signal path

- Customisable (features, metal anodisation, side panels)

Send me an email if you are interested in a Compactron unit. Also dealer inquiries welcome for this new product line.

Best regards



  1. Dear Thomas,
    I think this concept will win some new customers.
    I myself have been looking for high-end devices from Germany with a uniform, modern and functional design line for a long time.
    For me, installing the tubes in a closed housing is essential for two reasons:
    firstly so that my little son can't destroy the valuable tubes and secondly it is much easier to keep the device dust-free.
    Now all that matters to me is the acquisition costs.
    With best regards, Tim

    1. Hi Tim, contract me by email if you are interested in any of the Compactron line

  2. Herr Mayer

    Fantastic post, really enjoy seeing the whole and imaging a new set of hifi enthusiasts that this would appeal to! The design is very pleasing as well!


    1. Thank You! New chassis material just arrived for the next units in this series

  3. Blown away by that internal layout! Absolutely fantastic.