I do not find them noisy at all. Low Z or High Z.
Which tubes did you use when you experienced this? Did you swap the tubes out, or was this a quick demo type testing session? Certain tubes can be noisy and microphonic.
Edit: I hope you will provide some additional background on your comments…
The background is purely based on reviews, comments and stuff Justin from A&S has posted himself.
I think Torq has done some measurements with some of the A&S amps. I cant remember where he posted it, maybe earlier in this thread.
Im glad you are not hearing anything that is bothering you. It’s always good to have statements balanced. I am very sensitive to extraneous noise so anything that hints at an amp having that, that is more than a couple hundred dollars, is something that I try and be aware of. Even tape hiss is something I have a hard time with so there are a lot of otherwise good older recordings that I have trouble with.
From personal use I would opine they are reasonably quiet. My Encore has the input transformers and the Kenzie doesn’t. Good DACs behind both. Good headphones attached. If it’s noisy, I sure don’t hear it. I don’t get hung up on instrument measurements too much either. I have six headphone amps, and the Ampsandsounds are great units. The question was responding to @carsandcoffee looking for a device with inexpensive tubes. This is a good quality unit that fits the bill. Thanks for clarifying your comments.
Thank you all for chiming in! I have decided to get the Pendant.
Good choice. Congrats.
NO! WAIT!
Just kidding. NOS tube set as well? Zach’s selection is really good. I think you’ll really like the Pendant.
Quick note on A&S and noise:
I’ve had a Mogwai SE as my daily for soon to be two years now, and I can confirm that what @perogie is saying is definately not out of thin air even though he might not have hands on.
Now there might be many reasons for why this has come to be, but I think it’s fair to say that the origins of A&S amps are that of repurposed speaker-gear. Albeit for super sensitive speakers, still doesn’t really fit the bill for sensitive headphones.
The Mogwai SE i have is has around 2 times the noise floor of what is listed on the revised version. There is indeed audible noise on it depending on what you’re doing, but also ways around it for the most part once you know the amp well enough.
IME: What are the factors for when this audible in practice?
In practice sticking with the 8ohm tap, and it’s a non-issue for what i drive on it mostly to begin with. The 300 will always have noise no matter what i do to it, but the 32 is also “fine” with a low wattage tube roll config on stuff like Sennies and ZMFs.
It’s important to note that the original A&S amps only had 32 and 300 jack and were usually presented and reviewed with the full 8W tube rolls (KT88 or 6550 with GZ34/5AR4), thus presenting 2 quite noisy options. My Mogwai was the first one to get an 8ohm tap back in may of 2018 according to Justin, if it didn’t have it I would not be happy with the product to be honest.
I’d consider it an extra thought if i had a desire to run very sensitive headphones. But for most normal headphones you’d typycally run I’d personally not be worried, esp given the noise ratings of the current line. I would not pick up old 32/300 only models though.
I have Kenzie Encore 32/300 and Kenzie 8/300. 12SL7 and 1626 stock tube compliment. Not noisy with my gear. Can’t weigh in on the Mogwai or Mogwai SE. Different amps. @perogie
Loving the Rosson Audio RAD-0 on the Pendent tonight, running through Rolling Stones set. Just lovely.
I ordered a pendant as a bundle with a Verite C.
When the pendant arrived it had a bad hum and an intermittent crackling sound in both ears.
This was most noticable on the Verite, still there in an HD650, but less noticeable.
Emailed Zach, ended up sending the amp direct to A&S, short version is they couldn’t find anything wrong with it and sent it back to me.
I’ve actually resolved the crackling, for whatever the reason the amp picks up RF interference from my Wi-Fi, but the hum is still present.
I’m trying to determine what is “normal” ambient noise for these amps, this is what I hear
High output Verite C audible hum sounds like power or possibly transformer noise
High output HD650 barely audible hum
Low output Verite C barely audible hum
Low output HD650 no audible hum
This is with or without a connected input, and the hum volume is independent of the amplifier volume. I’ve swapped out the el84’s and 12au7, makes no difference. Tried different circuits in my house etc.
Is this normal for these amps?
I don’t think I can tolerate the level of ambient noise on the High Z through the Verite C.
It’s not quite ZDT Jr levels, but it distracts from an otherwise good amp.
I’ve had plenty of humming amps. Usually a ground issue, a tube, or simply a crap power/input cable that isn’t isolated from other sources of interference or is making a bad/lose connection. Hate to say it, but 90% of humming is environmental or gear related. And with the Dragon Inspire, it just hummed no matter what I did.
Is the hum loud enough you can hear it when music plays? What volume level does the hum become apparent? Is your DAC grounded well?
Does it even when not connected to the DAC.
I have other tube amps here, and outside the ZDT Jr, which when shielded is about the same, the other amps a BHC and a Tuba are close enough to silent I’d have to be nitpicking to say they had background noise.
It’s not terrible that’s why I’m trying to establish a base line, I’ve moved the amp to a couple of different locations around the house (different AC circuits) without the hum changing.
I do have another power conditioner on order which I’ll try if it ever ships.
If I used the HD650 for the bulk of my listening I’d live with it, it’s audible but not offensive with the Verite C (which I assume is down to sensitivity) it’s annoying, and I can hear it in very quiet music passages.
Also, power cables can make a difference, but I stay away from the audiophile snake oil BS.
All you will ever need:
Tried multiple power cables, multiple interconnects (Justin from A&S provided another to try), multiple DAC’s swapped in 4 different sets of El84’s, 2 different 12AU7’s.
If what I’m hearing is normal I can’t believe no one has mentioned it when “reviewing” the amp.
Have you tried skipping the power strip and go straight into the wall?
Yep, the only power thing I have left to try is to use one of the dedicated 20A circuits in my garage, so I know there is nothing else on the circuit.
Pull the battery from your car and wire the amp to run directly off that.
(Just kidding.)
You got me stumped.
This made me laugh!
Thanks, brother. 
