Regarding the public posting of schematics:   http://www.diyaudio.com/forums/headphone-systems/229934-version-o2-desktop-amp-oda-11.html#post3506094   Quote:jcx   http://www.head-fi.org/t/611348/help-needed-to-upgrade-the-capacitor-in-otl-tube-amp/15#post_8417041   Quote:jcx  ...

I remember starting that thread years ago (under a different user name). After my first haphazard test build, I eventually worked out the noise/hum problems by rebuilding it with a better power supply. The amplifier worked well afterwards. The output impedance of this amp is relatively high...

Regarding the recent SRM-252 replacement wall-wart discussion, here's a relevant link: http://tangentsoft.net/audio/wall-ps.html  

Quote:   Quote:   I wouldn't. Kevin Gilmore specifically recommended against using an unregulated supply in this post. http://www.head-fi.org/t/223263/the-stax-thread-new/22995#post_9532128 In all likelihood, the original unregulated 12V wall-wart was designed so that the...

Here's a possible solution for the SRM-252 power supply. This isn't really a recommendation as I haven't tried this one myself, just a suggestion. It could potentially be a piece of junk. http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_162996_-1 12VDC at 500mA with a...

Quote:   As far as I know, the Elpac WM series wall-wart that originally came with the Gilmore Lite is also linear regulated, but I understand what you're getting at. The audiophile in me would also immediately go for a linear supply over a switching one, if given the choice. My point...

The Stax SRM-252 and Koss E/90 have switching power supplies within close proximity to the amplifier circuit. They both work just fine.  

Thanks for looking it over. Most of the part values were chosen somewhat arbitrarily. Any improvements that you think are worthwhile, feel free to add.   On a side note, this schematic of the SRM-001 by kevin gilmore might be of interest.   http://gilmore.chem.northwestern.edu/stxp.gif

Quote:   It's just a derivation of an amp from tubecad. The load resistor value could be adjusted.   http://www.tubecad.com/november99/page9.html

A hand made triode. Video is at the bottom of the page.   http://paillard.claude.free.fr/  

Quote:   I can think of a few reasons. The old buffers are relatively basic implementations using few transistors and hence vaguely understandable to someone (like myself) with limited electronics knowledge. They all have a high quiescent current so they are more likely to operate in...

People fixate on price too often, and incorrectly assume that performance is directly related. I could easily live with the "mid-fi" AKG K702 or Stax SR-202 as an end-game rig.

I'm also interested, but quietly lurking as the discussion is largely over my head.

Quote:   Is it a CCFL inverter for LCD backlighting? I've wondered about the viability of using them for the output stage of a DIY electrostatic headphone amp. I'm not sure what the typical switching frequency is for those. IIRC, the output waveform is far from resembling a sinewave. I...