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Saturday, May 13, 2017

News from the ELROG Tube Factory 6


The staff at Deutsche Elektronenröhren Manufaktur GmbH worked extremely hard during the last weeks to finish and test our new tube developments in time for presentation at the High End 2017.

In the last update I already revealed the ER274B rectifier as one of our new tubes. Here it is complete with stamping and packaging:

In the last post I wrote that this is the very first thoriated tungsten full wave rectifier in tube history. This is not exactly true. The UX213 was a very early rectifier which used thoriated tungsten filaments. But it was mostly produced as prototypes and barely any were sold on the market. It was soon  replaced by the UX280 which has an oxide coated filament.

But nevertheless we are very proud of this achievement to offer the only rectifier on the market with the advantages of thoriated tungsten.

While other full wave rectifiers arrange the two plates side by side we stacked them on top of each other.

With a single set of filament strings running through both of them.

Here we see the rectifier in a test power supply. With the lights off it creates a stunning light show:

Having developed the ER274B, offering the 'A' version was a small step:

This is the same rectifier but with UX4 base instead of Octal.

Expect to see amplifiers from me using this rectifier soon!

But this is not all yet!

End of last year we announced the ELROG ER242, a variant of the ER211 with molybdenum plate. It took us longer than expected to get the peculiarities of molybdenum sorted out and to get the first batch of tubes.

Finally the first pairs will be shipped to those who placed pre orders. For these special tubes we also made a new packaging.

Thanks to all who pre ordered this tube. The deliveries will happen soon! Around October we will start another batch. Due to the difficult manufacturing process this tube will only be made in limited batches.

I often get questions about other new tube types. The tubes above will certainly not be our last new developments. But before starting any new types I would like to collect some feedback. We are considering development of these types next:

ER50 : A replacement for the famous type 50 triode
ER801A : A replacement for 10Y and 801A triodes
ER5U4G : Another full wave rectifier

Please send me an email or leave a comment under this post if you would be seriously interested in any of these types. Or leave suggestions for other tube types. In case there is enough demand we will start the next development in some form of crowdfunding scheme. Pre orders will be accepted for the new type and as soon as enough pre orders are collected the tubes will be made. In case the pre order process will not yield enough funds to start the development, those who entered orders will be refunded. This way you will be able to support the development of new tubes. Those who support us with pre orders will get a better price as that after market introduction.

Best regards



  1. Sir, please develop WE 212C tubes. We only have Chinese variants now but they are not very reliable. We need some German 212 tubes please.

    1. Thanks for the feedback. If we get more requests for that tube we can make it!

    2. I own a couple of WE 212C replica P-P amplifiers so if you ever will build german 212 tube I will buy them ;)

    3. Wow 212 PP! That must be some serious power. When we will have plant for a 212 I will announce it on my blog



    4. Yes. You can see my 212 P-P amplifiers here:


  2. ER801A, yes please. :-D

  3. Definitely the ER801A. Producing a driver / pre tube would complement your line very well and put an end to the low (or quasi non-existent) availability of the 10Y. With a ER801A one could build a complete two-stage amplifier, from rectifier to output tubes, with ELROG products from you company.

  4. Thanks for the feedbacks. An 801A seems to be quite popular indeed

  5. To be honest, I find 801a quiet a bit on ebay...they are still out there for prices which I guess the new Elrod will not be able to match. So, why going for the same thing for much more money ? Answer: Either there is a big difference in quality or people will not open their wallets....

    I found the 274b very smart: Take a already good product and bring it with true innovation to a new level...

    So, I guess my vote would go for innovation and differentiation. For example: A 841A with a much lower rp and a mu of 30, or a Th. Tungsten 520B where we can have much more power than 300B with the need to build lethal voltage 1000v psus etc....So, a product which is missing and were you can shine.

    1. Thanks for your feedback! Indeed an ELROG ER801A will be at a similar price level as our 300B. Completely new tubes are possible but with those there is the issue that there are no existing amps out there which could use them. So only people who build new amps fitting for it would buy it. Nevertheless we are considering such alternatives as well

  6. ER801A. Auf die warte ich schon eine ganze Weile ;)
    Eine Ba mit Wolframkathode wäre schön, interessiert aber wahrscheinlich niemanden.
    Alles Gute,

  7. How about 45? :-)

  8. Hello Thomas!

    You built already a considerable number of amplifers with 10Y/801a (line and Power). So, I would vote for the 801a which proved it's use as driver for 300B. Together with the new 274a/b a complete Elrog tube amplifer would be possible ;-)

    Best regards!

  9. The 50 type please! Also, you have built so many amps with 45 tubes I am surprised that you aren't considering an Elrog 45. I would be a customer for either of these tubes

    1. Thanks for the vote! In order to keep the tube production financially sound I need to consider tubes for which there is sufficient demand to justify the development. The amps built be me are not enough to finance the development cost.

  10. How about the 8417? Rare as hen's teeth, and still a bunch of amps out there that need them! Also, if you guys start making a 5U4G, we'll buy a bunch of 'em.

    1. Hi!
      We have no plans for a 8417. We can adapt the design of the 274B to be compatible to 5U4.