Tube Headphone Amp?

[kevinkr]

Originally posted by EC8010


How do you feel about electrostatic headphones?

I've never owned a pair, but I would assume (perhaps mistakenly) that their insulation is up to the task whereas I wouldn't make that assumption with a cheap pair of conventional electrodynamic headphones such as I usually use. I also imagine the cap failure could give rise to a rather loud, possibly ear damaging bang not to mention a possible fire in the headphone ear cup.

About 25 yrs ago I designed and built a wonderful sounding (well I thought so at the time.. ) solid state headphone amplifier with fully complementary output stage direct coupled to the headphones.. A defective output transistor resulted in a catastrophic event to my headphones, which fortunately were not on my ears at the time. (Basically slagged them.. ) Once repaired this amplifier worked flawlessly for >20yrs until I tossed it a couple of years ago as space was getting to be at a premium.. (i.e. Nothing inherently wrong with the design,) Caveat emptor as the Romans would say.. YMMV, etc..

[EC8010]

Odd you should mention fire...

Many years ago (before I was aware of the distinction between resistance measured by a multimeter and resistance measured by a high voltage tester), I made a pair of electrostatic headphones. Each driver was essentially two plates of perforated steel with a bit of cling film between them. A few bits of plastic clamped it all together and a pair of piano wires and a scrap of old jeans formed a headband. The plates were capacitively coupled to KT66 anodes. Insulation between the audio and ears was 1/2" of acoustically transparent foam (tested with aforesaid multimeter). They worked very well, although none of my friends would wear them (even before they caught fire while I was wearing them).

[woodturner-fran]

Yep, the high voltage is a concern alright. I was actually going to build the 24V aikido as I had most of the stuff excluding boards, tubes and chassis. i was going to use BUF634 on the output. In any case I went the other route. Still curious as to how it would have sounded - my 24V aikido preamp is excellent.