This is a classical OTL (Output Transformerless) headphone amplifier base on popular 6AS7GA and E88CC double triode
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On the schematic you will find one chanel of this amplifier so basically you need second one to have a stereo sound in your headphone.
Input stage I used quite good quality Alps 100KAX2 potenciometer with good compromise quality/price.
At this moment I've rebuild little bit filament for tubes and power supply for filament is 6.3VAC directly from the transformer.
Nice amp! As a Polish amp maker, I see some familiar components - the MLT and Telpod RDCO resistors, Tesla E88CC tube. I'd attach the main DC filter caps in a row using a metal strip or zip ties on saddles.
Doing away with DC regulated heater supply was a good idea, especially if it included the 6AS7G / 6N13S / 6080 tube. Too much current, too little SNR improvement at the signal levels we're working with.
An interesting project though the power supply seems overly complicated. I know mains transformers are expensive but it is much easier to get a 200/250v output transformer with 6.3v heater secondaries. The heater supply is taken straight from the transformer with no additional components. The HV could be generated using something like an EZ81 with capacitive input choke filtering. This will give B+ with ripple at -110.7dBv. and only need about 5 components other than the transformer. Superb performance with minimal components in a traditional design.
Simon
David Moreno Montero
RobG
mircemk
Ha, I wondered about the E88CC designation, and why not ECC88. According to http://www.r-type.org/exhib/aaa0037.htm :
The E88CC is a special quality double triode. The transposition of the figures from the end of the type designation to the middle was Mullard's way of denoting a special quality build.
Learn something everyday.