I have got an ARC SP11 which has had some comprehensive mod,s done to it which includes 6 SOVTEC ecc88 valves. What I am hearing now is a bright severe top end ( to my taste anyway) Does anyone know if a different valve eg a mullard would make the top end a little less harsh. Regards. Jim. p.s. this amp will be for sale in the near future if anyone is interested. my email: [email]email@example.com[/email] mob 07803054952.\r\n The rest of my kit is RESOLUTION AUDIO OPUS 21, a pair of MCINTOSH 501's and KRELL RESOLUTION 2's. I also have a DAX DECADE which I am trying to find a TRANSCEND for.