Problems with my Berning ZH270

George.
Please contact Andy at Vintage tube services, the RCA's seem to be the best bang for the buck.
Andy is the only other person besides David Berning and myself that have the perimeters of the amp and what the tubes require to be, Make sure you tell Andy it's for a ZH-270.

Hi Allan. How can I contact Andy?. Thank you.

George, my observations match those of Allan. If you follow his advice, and still have a problem with the high frequencies, I would again direct you to the Marigo dots, especially on windows.

You are in for a treat with Andy Bouwman's matched tubes. I recently put a pair of Andy's Sylvania 6SN7 tubes in the input section of my OTL amps and the high frequency performance was just outstanding. I have a complete set of Andy's Sylvania 6SN7's in my preamp and they were a great upgrade as well. His tubes are expensive, but well worth the cost IME.

If you end up trying the Marigo dots, I would enjoy hearing about your results. BTW, do you have windows in your listening room?

George, Andy's phone number is 616-454-3467, you may also want to try the ERS kit, it's substantial, as I am sure all the other Berning owners will tell you, it's more than any tube change.

Hi Allan and thank you. For wellfed, I have 2 windows covered by courtins, thanks.