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Friday, April 3, 2020

The New 45 Drives 45 Mono Amplifiers


It's been a while since I built 45 power amps with 45 as driver tube.

Here a pair of newly finished amplifiers in that configuration.

About to be shipped to their new owner in the US.

The amplifiers use a 45 in the single ended output stage, delivering about 2W.

The output tube is driven by another 45 through an interstage transformer.

The input transformer offers the possibility to have a balanced XLR input.

The amps have been constructed in the tower style chassis using all the latest construction techniques which evolved over the years.

A few photos showing the construction process, starting with the raw top plate.

Sockets and meter mounted:

Some components are mounted underside of the top plate via threaded blind holes:

Initial wiring:

Adding the capacitors which are closest in the signal path:

Interstage and output transformers reside on a separate sub assembly along with more capacitors and chokes:

The power supply section:

LCL filtered filament supplies for zero noise operation even on the most efficient speakers.

Adding the sub assemblies layer by layer, with additional plates in between for mechanical ruggedness:

The completely assembled amp, without enclosure, ready for testing:

Some more pics

Best regards



  1. Beautiful Construction, a work of art

  2. Beautiful design Thomas, but 2 questions:

    1) Are Hashimoto interstage /output transformers comparable to Tango technically or spec wise? Build quality?

    2) Is the basic principle behind same tube as driver/ output a way of cancelling distortions similar to a Japanese designer, I believe Sakuma made popular?

    3) Cost estimate of this build?


    1. Hi!

      1.) depends what you compare, pls check the datacheets.
      2) no
      3) this type of amp is only sold as finished product. if you are interested please email

  3. Really rather spectacular. Love the industrial design and the mass of iron, attention to detail, super caps.