Aesthetix Calypso and Berning ZH270 combo noise.

Could it be because both of the amps using switch mode power supplies?

Hi Nr9, I have a Berning Switch mode tubed powered pre-amp ( yes a tube switcher), a Berning Switch Mode powered tube BAM, (Don't ask and I lent it to profone, who still has it and does not want to give it back :)) and a Berning SMP supply Headphone amp, two Berning mono amps with 1 Farad of power supply capacitance each also with switching power supplies without adjustable gain and noise is absolutely not an issue.

I have had complaints with a couple other pre-amps with regular power supply's as well being noisy ( and tested as such), it's an issue of sometimes higher residual noise of the pre-amp design or sometimes noisy tubes, which a most other power amps do not have the sensitivity to show up.
Our first switch mod pre-amp was in 1984 the TF-12 and TF12B, B for Balance, No issue with noise on the ZH-270 with the TF-12.

This is one of the reasons that we have the adjustable volume control on the ZH-270 and why we would not do amps without these unless we do our own matching pre-amp.

You may want to reduce the sensitivity of the amp by reducing the gain on the volume control.

If I adjust the volume to "16", the preamp is much quieter than "17". There are more similar steps up. I have not heard this before when I used it balanced.

"17" could be a higher gain step than the other preceding ones.

If you turn the volume control on the ZH-270 up to full, you may encounter the noise at a lower level setting, and if you reduce the volume control on the ZH-270 you may encounter the noise at a higher level on the pre-amp, but it's there in the pre.

The ZH-270 because of it's unique design is able to have very high sensitivity and low noise, I know of no other power amp with this capability, the volume control is there so that you can adjust the input sensitivity to allow the use of varying pre-amps.

Are you using a power conditioner?

I have a Hydra 8, but the use of it doesn’t affect the noise at all.
The strange thing is that the noise is rising and dropping a lot when only a slightly change in volume setting is done. (+/- 1db). Example: The noise is high when the volume setting showing “40”, but it is low when showing “41”. This is happening between more steps. I have tried to change the tubes to different brands, but the noise problem is still there. I have just bought me a new Joule Electra LA 150 MKII. Hope this will solve the problem.