Excellent HeadAmp for high impedance phones:   http://www.hpas.estranky.cz/fotoalbum/tube-headamp/#photo_63   Very interesting.

Main handicap DT990 is small max.power load (0,1W). 990s resents high volume with bassboost. ATH-A900X tolerate much more (2W). With active bassboost circuit is A900X absolutely best worker.

Please can I use Mosfet Diamond Buffer with symmetrical supply? Please exist some replacement 2N5486? I can't get it.   Thank You.

Quote: Originally Posted by Pars Looks OK, though there are some things I would change (TO92 footprint, add paralleled emitter resistors as the original, and use the 2SJ109/2SK389 footprints in order to take advantage of dual heatsinks for starters). Nicely documented, though you appear...

Quote: Originally Posted by Ferrari .........One small comment, I have got the feeling that the value of R1 (10KΩ) is on the low side when a 50KΩ or 100KΩ volumepot is used. I think that it’s better to change the value of R1 to 1MΩ and add an extra resistor (R0) of 475Ω (or values in...

Quote: Originally Posted by FallenAngel Uhm... how is this "better" than the current Dynahi boards? Function is the same, it's only smaller. The original is unsightly, unprofessional appearance.

Quote: Originally Posted by DarKu looks very interesting, but where to buy the PCB ? This is only a proposal. Inspiration for the manufacturer of the original board. Unfortunately.

Modified PCB, only 86 x 70 mm Complete high quality PDF documentation .