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Thursday, August 27, 2015

211 -The Next Generation- Part 7 : 801A Drives 211 Assembly


Assembly of the second set 211 mono amplifiers of this year has been progressing well. The amps are now under test and will receive the final wooden enclosure when testing is finished.

Here a few photos of the assembly steps, starting with the top plate of an amplifier section:

All transformers, tube sockets, resistors and some of the caps are already mounted and wired up. All remaining parts are mounted on a second level below the top plate:

The completed amp without wooden enclosure:

Testing is done on the open amp to have access to all relevant points for measurements. The terminal plate is provisionally attached for the tests:

The power supply sections are constructed in a similar manner.

Mounting of the power transformers:

Two of the transformers are mounted in cut outs and a bit recessed below the main plate since they would others be too high to fit under the transformer covers. Wiring of the high voltage power transformers and tube sockets:

All chokes  and the remaining capacitors are mounted below the main plate. Here the finished power supply ready for testing and before the transformer covers are added. Quite a mountain of iron!

The amps running in the system for an initial listening test.

Stay tuned for photos of the finished set!

Best regards



  1. Hi Thomas,

    A bit off of the topic, but have you made a PX4 or PX25 amp?
    Those seems very interesting sounding tubes.


  2. Where do you get the slotted angle steel?

    Thanks for a very interesting blog.


  3. These are made from aluminium. You can buy them from me