All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.

Wednesday, September 30, 2015

211 -The Next Generation- Part 11 : 801A/211 tower, amp assembly


The next set of 801A drives 211 amplifiers shares exactly the same circuit with the already finished amps. But it will be in a different chassis in 'tower style'.

Everything will be mounted on metal plates, stacked above each other:

The top plate carries the two tubes and the signal transformers:

The bottom side of the top plate showing al the signal wiring:

The small transformer on the top left is the input transformer which is wired 1:4. This way the amp has a sensible input sensitivity with only two stages.

Handles and vertical mounting bolts added:

Capacitors and chokes are mounted on a sub assembly and pre wired:

The sub assembly added to the amp:

The amp ready for testing:

In the next part I will show the assembly of the power supply.

Best regards



  1. Hi Thomas,

    Very clean build (again..) I like the minimalist look on top. For this build you use 1:4 input transformer ratio for the 801A. For your 45/45 amps do you use a higher ratio like 1:8? Thank you.

  2. Hi Rick,
    I select the step up ratio depending on the gain needed in the system in which the amp is
    going to be used. I try to keep the step up ratios as low as possible


    1. Hi Thomas,

      Thanks for the reply. That was helpful info..