@chungjh,
I’d call Wayne at Pass. Two things still come to mind. Re-check bias on your Pass amps, re: slow warmup. Some do get sent back and get re-checked after some run-in time. Concerned for you that your SL 545s might suffer with any lower power tube amps. I run capable 120w KT150 mono tube amps with larger transformers myself, and I’ve heard your same speakers with my 120w tube amps. As I recall it was still on the edge of being "just enough", maybe. I still wonder if your preamp is not driving the amps well enough. Separate topic, ask Wayne. Read this article to refresh thoughts about the type of amplification to make the 545s sing.
This review reminds me of a few things to pass along about "power" vs. current for your 545s. https://www.dagogo.com/sound-lab-ultimate-545-electrostatic-loudspeakers-review/2/
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I’d call Wayne at Pass. Two things still come to mind. Re-check bias on your Pass amps, re: slow warmup. Some do get sent back and get re-checked after some run-in time. Concerned for you that your SL 545s might suffer with any lower power tube amps. I run capable 120w KT150 mono tube amps with larger transformers myself, and I’ve heard your same speakers with my 120w tube amps. As I recall it was still on the edge of being "just enough", maybe. I still wonder if your preamp is not driving the amps well enough. Separate topic, ask Wayne. Read this article to refresh thoughts about the type of amplification to make the 545s sing.
This review reminds me of a few things to pass along about "power" vs. current for your 545s. https://www.dagogo.com/sound-lab-ultimate-545-electrostatic-loudspeakers-review/2/
Quote:
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(At 86dB efficiency with an 8-ohm impedance, the U-545 needed more wattage than current in amplification, so a high-output Class AB would be more appropriate generally. But the XA200.8 is Pass Labs’ most powerful Class A monoblocks in its ‘High Current’ series, occupying only two chassis and second-in-line to the company’s four-chassis, $85k Class A Xs 300, therefore provided the necessary wattages in high-current drive and propelled the panels to enormous scale and performance)