DHT headphone amp

[merlin el mago]

If you already have an output transformer, than what is the primary impedance of it?

15K

 

[merlin el mago]

The Raytheon 307A/RK75 it’s a true 307A https://www.radiomuseum.org/tubes/tube_rk75.html

 

[56085]

I do think that the chance that the Raytheon 307A/RK75 and the Western Electric 307A are equivalents is very big.

But mistakes can happen, even on a site like Radiomuseum.org. I know this because I found a lot of mistakes in a tube handbook of which the diagrams are being used by Radiomuseum.org on many of their pages on tubes. I sent them my list of mistakes, which they did use to correct many of the wrong diagrams on their site. See:

Radiomuseum.org - List of errors in Electronic Tube Handbook Muiderkring

 

[merlin el mago]

If you already have an output transformer, than what is the primary impedance of it?

I have 15K-600R, 15K-300R, why?

 

[56085]

To be able to draw a loadline (for the 15K-300R case).

 

[merlin el mago]

OK thank you.

 

[merlin el mago]

I’m thinking, with a 3a5 voltage amplifier and 307a as cathode follower driving a step down transformer, the distortion of the 307a is going to be low is it not?

Do you have schematic?

 

[Bigun]

no I've never had a 307a to play with although I do have some 3a5's.