Are SET amps "quieter" than push/pull tube amps?

@bobbydd Wrote:

I ask as I was considering combining horns with either VAC or ARC amplifiers.

I would also look at Quicksilver audio, the Horn mono amp is designed for high efficiency horn speakers and is a push pull amp. i.e. Lower gain. See below:😎

Mike

https://quicksilveraudio.com/products/horn-mono-amp/

https://www.stereophile.com/tubepoweramps/581/index.html

+1 @atmasphere

OP   is it that most tube amps have too low a signal to noise ratio?  Or some other factor?

The reason why audio systems are noisy because all audio systems sound unnatural. The natural sound is very quiet.

In below video, 
1) From 0 ~ 0.07, both spkrs sound fine because your ears adapt quickly to sounds.

2) 0:08 ~ 0:22 the natural sound spkr sounds quiet (no bad noise) and fine.

3) 0:25 ~ 0:35 the unnatural sound spkr sound OK (with some bright noises), your ears quickly adjust to the unnatural sound. ** Your ears are biased and in unnatural sound mode now.

4) 0:37 ~ 0:44 the natural sound is weak and unclear because your biased ears are not quickly adjust to the natural sound since unnatural sound is powerful and harsh. Natural sound is soft and delicate.

5) 0:52 ~ 0:59 Your ears recovered with my voice support. Your ears are in natural sound mode now.

6) 1:00 ~ 1:25 the natural sound spkr sounds fine.

7) 1:27 ~ 2:00 Your ears are confused between natural sound (my voice) and unnatural spkr sound. Your ears switch very fast between my voice and spkr sounds to comprehend both. **Lot's of listener's fatigue this stage. All hi-fi systems sound/behave like this and results much listener’s fatigue between natural sounds (dog’s bark, kitchen sounds, people talking, car sounds, etc.) and unnatural audio sounds. Therefore, hi-fi audio listening is preferred at quiet late night.

8) 2:05 ~ 2:18 your ears are easily adjust to the natural sound with my voice. Notice the natural sound is very quiet.

All audio systems in the world behave like the left speaker and you will hear some noises from an audio system. Alex/Wavetouch

Killing me softly - (Natural vs. Un-natural sound), PA speaker comparison.

Can anyone explain to me why a low powered SET would be more "quiet" and work better with such speakers than an ARC Ref 75 or VAC 200iq (as examples)?

@bobbydd Yes. The dealer is incorrect; PP amps are not noisier. But, and this is a big one, that depends on how much gain the amp has.

SETs tend to not have a lot of gain, because they don't make much power and are intended for use on high efficiency speakers. PP amps usually make more power and so usually are on less efficient speakers- and so are designed with more gain.

The gain differences described allow preamps to be more or less universal. A typical line stage might have 10-15dB of gain; if you properly match the amp with the speaker you can use the same preamp with a high power amp with less efficient speakers or a low power amp with speakers of high efficiency and have the same noise floor and use the volume control the same way.

If you combine a high power amp that likely will have 30dB of gain with a high efficiency speaker, you'll be battling a noise floor of hiss, hum and buzz.

So SETs are lower noise simply because they usually have less gain and for no other reason. Obviously, if you have a lower powered PP amp with the same gain, it can be perfectly quiet too.

You can get PP amps to be silent on horns. But you might have to jump through some hoops to make it happen and that might be a problem with larger ARC stuff.

We've been making PP tube amps that compete easily with any SET for musicality, but our amps are unusual in two ways that have to do with horns. First, they have no output transformer (and are otherwise triode and class A; hence the musicality). Second, we make a little jumper plug that allows the user to remove one of the driver tubes and replace it with the jumper, which drops the gain about 12dB without changing its output power. This helps them be quiet with horns and still easily driven by any preamp. I don't think ARC has anything like that, so whatever their noise floor is, about the only way you can improve on it would be to seek really low noise driver tubes for it.