Just to report that I have, I hope, got myself a working pair of ESP-6A. The shattered diode is the only fault found so far and the replacement of that has made the bias behave. I am starting to get used to listening on the set and I am enjoying the experience although I have only dynamic...

All the other diodes are reading as they ought to on a meter although they may be off spec on full voltage. Looking at the diagram kindly posted by Edstrelow I cannot see that a transformer short would do other than prevent the set from working. I have run these off the loudspeaker posts and...

Visitors gone and I've had a chance to examine the ESP-6A headset more closely. I've cleaned the boards and removed the deteriorated damping. However the real news is that the third diode from ground has failed explosively although the others in the stack seem to be in order although they may...

Quote: Originally Posted by spritzer Extra capacity can help but it depends on how much bias the phones are leaking. A Stax Lambda can run for at least 15 minutes on the bias charge before they drop much in volume and the same goes for many other phones. I would try some new caps...

Quote: Originally Posted by edstrelow I have added the front and back of the instructions for the adapter box, which includes the schematic for the box on the initial posting. The ESP6a, which I originally owned, also came with a similar adapter box as the 6. If you don't have the...

Quote: Originally Posted by spritzer Mine were pretty beat up when I got them and didn't work at all. The removed the electronics and all wiring and converted them to the Stax standard plug. Then I cleaned the boards as well as I could, lifted all bad traces, resoldered all connections...

Quote: Originally Posted by spritzer This was a big problem for Koss back in the day. Everything is connected together to ground and many amps don't like it. The grounds for both cups are connected together in the TRS plug so lifting one return should have impact on performance...

Digitised my vinyl some years ago so would suggest that you look at the free Audiograbber which is the prog I used for extraction and which is fairly versatile. Surface noise is the root problem and I filtered with the facilities of Goldwave (Wavelab is also good). Guard against overfiltering...

Newcomer here so hope I'm not chewing over old fat. Been looking for info for some time on the old Koss phones since I picked up an ESP 6A headset minus interface box for one pound (US$2.00) at a fleamarket. After repairing the leads which had failed at the entry point to the left cup the...