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Saturday, December 17, 2016

The 46 Back in Black!


As much as I like building multi chassis amps with silver/finemet transformers and large transmitting triodes, I also enjoy doing more budget stuff like the amp I am presenting today. A stereo single ended power amp with the 46 as output tube.

This amp is in the classic landscape layout:

It comes in the same black and silver color combination as a 6CB5A amp I built last year and it will be used in the same system as that amp as part of an active set up with the 46 powering the midrange or highs.

Pricing for such amps starts below 4.000,- Euros.

This particular amp has balanced inputs but of course it can be built with RCA inputs as well.

This is actually only the second 46 amplifier I built so far. By coincidence I just had the first one back for service. The first one has a similar style. Only some construction details have been improved in the meantime. Here a photo of the older one:

I always knew that the 46 is a great tube. The first time I used it is almost 20 years ago. I had excellent results using it as driver in a 211 amp. The amp above was serial number 46 of my amps so I used the 46 tube as a gag. However it sounded simply great.

Now I had some time to listen to the old amp after servicing it and to this new one. The 46 definitely deserves more attention. In fact it beats the 45 in terms of sheer fun, musicality and tone. The only drawback ist that you only get 1.25W out of it. Not more. A Watt and a quarter. That's it. But as has been said before: The first Watt counts. And with the right speaker this amp is stunning.

Does it have the resolution and refinement of an Elrog 300B? No of course not. Also not the authority a well implemented 211 or 845 can produce. But it is the kind of amp which you will forgive it's weaknesses and enjoy.

I will cover the 46 again in the upcoming tube of the month post since it is such a great tube. But now some more details about this amp. The rectifier section uses my usual TV dampers:

Everything is mounted in a single chassis which saves cost and space. Here the top plate:

Capacitors, resistors and mains transformer mounted and pre wired:

The output tubes are AC heated from a separate filament transformer which is added to the lower right corner:

Input, interstage and output transformers as well as the chokes are mounted on a separate plate:

Here the inside of the finished amp:

The amp with globe 46 tubes:

After the results from this little gem, I am wondering how a 46 amp would perform with silver transformers and a driver with directly heated tubes like 10Y, or maybe another 46.

It is surprising how loud you can play with only 1.25W. It can make my Wolf von Langa B&W speakers go really loud with deep and well controlled bass.

Stay tuned for more about the 46!

Best regards



  1. Uh oh, the secret's out! I love the 46, have been using it in my monoblock amps for the past couple of years. The circuit is a variant of Gordon Rankin's Bugle 45, with silver outputs. Really wonderful sound.

    1. Hi! I wouldn't say it is a secret. The qualities of the 46 have been repeatedly reported by various people. I think it is mainly the very low output power which is even less than the 45s is what keeps people from using the 46

  2. Hi Thomas,

    Have you tried 46's in a line preamp before? If you did, how did it fare? Thank you.

    1. No, I only tried the 45 in a line and didn't really like it much there. But that says nothing it always depends on the concept not just the tube.

    2. Thanks Thomas.. It would be interesting to try the same circuit/iron as your 45 line preamp experiment but using the 46, but of course with different sockets or adapters.. Hoping that it still has the fun, musicality, and tone going for it..

      Warm regards....

  3. Hej Thomas, I have a 46 as above, I am struggling to get new/NOS Type 46 tubes, any pointers please


    1. Do you mean you have an amp like that? 46 tubes are more and more difficult to find these days. I have not bought any in a while since I have enough stock so don't know where to get any now