Tube rolling in Cayin A-88T

My stock power tubes are EH6550. I have been using GEC KT88, much better sonically. You should replace the stock input tubes, which will result in big improvement. Syl 6sn7w will shine from top to bottom. And RCA 5891 is a good match. The final result is the brilliant sonic house blowing up lots of much more expensive amps. I will be trying the GEC copy version of the Chinese KT88 very soon.

A Tripath TEAC sounds very good with my 96 db speakers, better than the Cayin so far...

I changed to the 8 ohm terminals, and the sound improved a lot, still a bit bright with some recordings, but acceptable now...

I guess some more playing will make it fine...

But I am worried with a THUMP on the left speaker when I switch off, only sometimes, and loud HUMMM, also from the left speaker, and also only a few times, when I turn it on, it stops after a while...

Thanks for your help...

I switched the pre-amp tubes, left with right, to check if it was a bad tube, so far no more THUMPs or HUMMM, knock on wood...

I always read that amplifiers shouldnt be connected to mains filters, but, as the Cayin only uses 280 watts, I connected it to my ESE labs Balanced isolation transformer...

Well, it did almost the same it did to the TEAC, smoother highs, more body, darker background...

Its getting there, and no more THUMPs or HUMMM yet...

Tubes are not for me, no patience for HUMMM, and THUMP, and adjusting bias, and not so good sound, so it is packed and will be returned today...