FWIW I tried a lot of things (pretty much everything short of a regenerator) to resolve the barely audible hum on my pendant on the 300 Ohm tap, and nothing really worked.
I’m not even sure the issue is power quality, the AC is clearly the source of the noise, but it’s unclear how it’s getting into the output, it needn’t be bad power, it could be something as simple as the designs routing AC lines next to output lines internally.
It seems to be a common theme on Justin’s amps, it frustrated me that he denied it was an issue, then claimed it was normal, when his amp is the only tube amp (excluding the ZDT Jr which had transformer shielding issues) I’ve ever owned with noise floor issues.
The matter is deeper, either the transformer itself or lack of competence to get the whole thing reduced to a size that fits.
Without wanting to be presumptuous towards A&S.
Someone mentioned that he has the transformers wound.
The other thing is that throttling is supposedly the key to getting a noise free amp.
NO idea why I didn’t try the stupid little O rings years ago on my OG AmpsandSound Pendant amplifier tubes. I’m a dumbass, all my tube based noise issues finally went away
No more tube crackles, pops etc. I still can’t / don’t push the gain past 2- O’clock -ish, there is still a bit of tube hiss that can be heard when the gain is up that far. It’s bearable but I don’t care for it, not that I could or would ever expose my ears to that much volume, it’s totally ridiculous and completely unsafe even for short bursts, this amp continues to be a powerhouse.
I’m feeding it w/ a pre-amp which gives me all the control over volume I need and it’s still a great amplifier for my planars which continues justifying why I have stuck with it for so long.
I’m also NOT sure why but when my cell rings I have not gotten the RFI interference like I used to in the past I’ve had a cell phone near the amp all day and it hasn’t been an issue during the few texts and calls I received today.
I’m not complaining and simply pleased, unfortunately I can’t offer a solution for why the past noise/interference issues from the cell are not affecting the amp today.
I did learn that the inexpensive silicon O rings will smoke and break when used on the power tubes, I’m going to order some 70 or 90 duro O rings made from “VITON” that are more specific to high heat. They cost allot more but I have had the regular silicone rings smoke and bust on another tube previously so I’m not going to cheap out this order.
NO idea why I didn’t try the stupid little O rings years ago on my OG AmpsandSound Pendant amplifier tubes. I’m a dumbass, all my tube based noise issues finally went away 
and completely unsafe even for short bursts, this amp continues to be a powerhouse.
I’ve had a cell phone near the amp all day and it hasn’t been an issue during the few texts and calls I received today. 
