Giant 2A3 Headamp

[L0rdGwyn]

Yo!

Showing off another completed build. Another one for my buddy Zach of ZMF Headphones. This is a cost-no-object 2A3 headphone amplifier featuring nanocrystalline core interstage and output transformers from Monolith Magnetics. The transformers are huge given the high permeability cores, and as such the amp is huge, and heavy! But hey, this is for the ultimate tube and headphone enthusiast.

Anyway here are some high level details of the build:
- Custom mains and filament transformers from Monolith Magnetics
- Maida style B+ regulators, shunt regulated bias supply feeding the bias pots
- Rod Coleman filament regulators
- 5687 / 7044 / E182CC input stage, LED biased
- Monolith Magnetics nanocrystalline core interstage transformers
- Fixed bias 2A3 output stage
- Monolith Magnetics nanocrystalline core output transformers with 120ohm, 32ohm, and 8ohm taps
- Vintage Amphenol tube sockets
- Simpson milliammeters

Here are some basic measurements:

1mW into 32ohm 0.036% THD
1mW into 120ohm 0.0066% THD
1mW into 300ohm 0.020% THD
1W into 32ohm 0.36% THD
1W into 120ohm 0.35%
1W into 300ohm 0.21%

The circuit.

And some pics of the final build.

That's it, thanks for checking it out!

 

[Redver]

Great build, do you sell these? If so how much, Ta.

 

[L0rdGwyn]

Sorry, I don't sell. I do have a commercial amplifier coming out through ZMF Headphones however, on May 10th.

ZMF Aegis Official Thread

This is a thread to discuss the collaboration between ZMF and @L0rdGwyn on a commercial version of the wonderful Aegis amp that he designed and released to the world. Here are some preliminary pics of the production version of the amplifier: You can read about the origins of the amp in...

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