211SE with 14K Trs

[L CAO]

With 211 tube made a single-ended power amplifier, the use of a 14K impedance of the output transformer, so you can not loop negative feedback.

 

[L CAO]

EF91+5686+211

 

[L CAO]

EF91 & 5686 are triode connected.

 

[L CAO]

Test Results:

1 watt output frequency response:


8 ohm 10 watt output frequency response:


Output power VS distortion:


FFT:

 

[L CAO]

211 operating point is: 1000V 60mA

 

[jazbo8]

They are beautiful, and thanks for sharing the design!

 

[waltube]

The FB loop exist
Not from out but from driver stage

Walter

 

[rdf]

Test Results:

That's truly impressive performance. What are the output transformers?

 

[artosalo]

Performance (THD vs. output power) at 1 kHz is not fully informative.
But how is it if measured below 30 Hz.

 

[Lingwendil]

Clever feedback, clean assembly, and nice numbers. Great build. Glad to see a little feedback in a DHT design, the zero-NFB craze is too overdone and it's nice to see something that isn't just thrown together!

Great job.

 

[L CAO]

DIY.
It seems there is no similar product on the market, the use of EI core, size 114 × 50

 

[RajkoM]

>> DIY <<


Great !!

 

[jazbo8]

Lao Cao is a manufacturer, but chose to share his design, I think that’s great.

 

[pieter t]

Lao Cao is a manufacturer, but chose to share his design, I think that’s great.

Agree, but Lao Cao being a manufacturer this thread is in the wrong forum

 

[jazbo8]

There is no problem as long as he is not selling.

 

[pieter t]

Promoting comes first, selling next

 

[RajkoM]

I agree with jazbo.
At manufacturer forum I would never have looked at this design.

 

[jazbo8]

We’ll see, if it does happen, the thread can be moved.

 

[L CAO]

I know the rules, in the forum I will not have any business practices.

 

[rdf]

Agree, but Lao Cao being a manufacturer this thread is in the wrong forum

Full circuit, with measurements, and no contact info. It's the right forum.