I have a couple of old tube radios but I have no experience with tube HiFi equipment so thanks for the advice. I bought this receiver in original condition and I just finished recapping and cleaning it. I have a low volume staticy-crackle in Channel B after about 20 minutes of play that does not change with the volume. I've deoxit'ed all the switches and pots plus the static doesn't seem to be influenced by any of these anyway. I expect that this problem is probably a tube but please correct me if I'm wrong. The pre has a channel reverse switch so I can change the input from Channel A to B, the crackle stays in B so I've deduced the crackle is after the phono stage somewhere in the 3 pre-amp tubes, main power tubes, or associated circuits. I'm starting with the pre-amp tubes. I didn't want to spend too much on tubes as I don't know what sound I'm looking for but I need a 12AU7 and a couple of 12ax7s that I know are good to troubleshoot with. To this end, I ordered a reproduction TungSol 12AU7 /6189 and a matched pair of JJ high performance 12AX7/ECC803s. After I figure out my tube situation, I'll try the JJs in the phono stage and if they don't sound good enough I'll get something better and move these to the other positions. As far as the power tubes, I have a couple of good matched pairs of the 7355s (not a quad unfortunately) but I know there is biasing needed to mess around with those so I'm going to eliminate everything else first. Thanks again for any continued advice.
Harman Kardon TA5000x pre-amp tubes
I had a scratchy sound that I deduced was the 12AU7 in my pre-amp section (discovered by the near-source soldering iron test) . I had an old one that I expect is weak (i have reasons) but works; it fixed the scratch. I m considering changing out the full set of pre-amp tubes (4x 12 AX7, 1x 12AU7) and I'm willing to spend about $20 per tubes. I was looking at some of the less aggressive Groove Tubes and would like some advice. Is this worth doing for the $100 or so I'm willing to spend and are Groove Tubes a good pick?