I have an ARC Reference 160s as well. My preference is to get the tubes from Audio Research... because they extensively test them and I want to support this great company. I have a spare quad of power tubes I bought from Upscale just in case I needed for testing. In general, I don’t tube roll with Audio Research equipment as they were carefully voiced. That said, a friend of mine tried a GE NOS 6550 in his ARC Ref preamp an liked it... so I ordered one just for fun.
Which tubes to buy
I have an Audio Research Ref. 160s power amplifier. It's almost time to replace the tubes. This will be the first time I replace the tubes in this amp. In the past I have purchased tubes for my Ref. 6SE preamp directly from Audio Research or Upscale Audio. Audio Research furnishes Tung-Sol KT 150 tubes with the amp. and also as replacements. Recently I have found PSVANE brand tubes available. Does anybody have experience using these tubes? I'm trying to get the best sound quality. Tung-Sol made in Russia have been around a long time. PSVANE made in China is new to me. Any suggestions or recommendations?