Hello. Since I have the same USSR 6P6S (I have a production year of 1964, but it should be exactly the same)... and they fit exactly without being 1 mm apart. I also think the quality of the sockets for inserting into the Cayin is very good I had the problem once with an amp, but it was only 1...

Hello dear elig63: I can´t answer that question, all I can tell you is: I tried this little baby here , that should be an isolator, it looks totally cuddly and cute, but it hardly helped me, yes it reduced the intensity of the disturbing noises, but in the end you could still hear the...

I hope it gets not too much off topic for this HA-3A thread. But data streams via USB and tube amplification are also an important topic. And the HA-3A is a powerful and just wonderful amplifier with such a strong character, I love it and don't want to give it up anymore ! But I think that...

First of all : congratulations to your HA-3A. I had the same problem because my DAC is connected to the PC via USB and the DAC is the pre-amp for the HA-3A. SPdif does not transfer these, that is correct. And luckily you can use it. But what do you do if you want to transfer via USB? I've had...

Hi @all. This is my first comment here. I just want to say thank you for all your great suggestions and recommentations. I've been reading this Thread for a while and it was the starting point for me to buy a HA-3A. I've been a proud owner of this headphone amp for 3 months now and I have to...