Fabian85

So probably go with the 32 ohm version then?

Thanks for the replies... gave up the rev2 PSU as I could not get it fixed. Just built the zener supply running perfect with +- 22V. Anybody tested different OPamps? Currently using OP27P... How much bias you would recommend maximum? Using the 63,5mm version and they barely get warm at 125mv (if I use Nelson Pass' of heatsink temperature analysis: less than "Blimey Hot", which means >10s hands on, so less or around 45°C). What kind of headphones would you recommend for this amp? Thinking about DT-880-600. Should be at a reasonable price... Thanks for all who helped to realize this project. A great sounding amp!

Thanks for the reply... was able to test the amp, working and sounding good... My PSU is making some... weird behavior... I exchanged all the semiconductors, tested the values of the resistors. At startup I get +24V / -4V... shorting legs 3 and 4 of the OP27 GP on the negativ side with a screwdriver for a glimpse of a second, the PSU shows +22 -22V... anybody an idea?

Long time reader, first time poster... Bought the boards from a member over at DIYA... this amp was going to be my first step into headphone listening. Starting by quoting Rod Elliot: most problems in circuits are due to incorrect parts... built the amp according to BOM, fired up the PSU (v2), checked voltages, all is fine. Hooked up amp (without OPAmps in place)... smoke in front of Q23 on the 2R Resistor... checked the PSU again: fried. Checking amp board... reverse installed Q24 and Q26... I am waiting for the PSU replacement parts. Meanwhile I desoldered the incorrect installed MJF transistors and placed in new ones. Any idea what to replace before hooking up the repaired PSU? Or should I just do a power up and see? Regards, Fabian