Portable battery powered headphone amp?

[Spraiski]

Does anyone know of a design for a portable battery powered headphone amp?

I am looking to drive a pair of iGrado's (they use the same 32ohm drivers as the Grado SR60's).

[Spraiski]

I should probably mention that I'm not opposed to a solid state/tube hybrid solution.

[Spraiski]

What does everyone think of this design?

http://www.fa-schmidt.de/YAHA/index.htm

[TomMcNally]

Well ... I don't see the point. Tubes running on battery power basically kill the batteries fast. Normal tubes running on 12 volt B+ are more like "gimmicks" in my mind than actual amplifiers.

... tom

[sorenj07]

CMOY.

[Spraiski]

Well I've already got a cmoy

I'm aware of the battery draining nature of tubes - but a 12v 2Ah lead acid battery wouldn't be out of the question.

I thought that the 12v B+ was a little fishy. Does anyone know of a non-gimmicky design?

[EWBrown]

Some of the "space charge" tubes (from the late 50s / early 60s) which were designed for 12V B+ (and filaments) wil lrun niely o 12-24V B+, but their gain and overall output voltage "swing" are severly limited...


You still need some solid state to develop any useful power, even at headphone levels.

John Broskie, on his Glassware / Tube CAD site had an article about a 6GM8 based "Aikido" HP amp, which used three-terminal regulators as the output power elements, and he even had special boards designed for this purpose.

/ed B