SET vs OTL

I owned an OTL amp for 8 years and then switched to SET. No one has mentioned that OTL amps require many output tubes. For example, my OTL amp had 8 output tubes. The obvious issue is that OTL generates a lot of heat, but also with that many tubes, there is more potential for tube hiss and other tube related noise. I was always tracking down a gremlin. My OTL amp always had tube hiss through the speakers, but the more annoying thing was dealing with tracking down the cause of humming noise that would arise. When my amp was quiet (albeit with the hiss still there), it was glorious. I’m not saying that other OTL amps such as Tenor or Atmasphere have noise related issues, as I have no experience with those brands, but mine did.

My current SET amp has been 100% reliable since I got it over 5 years ago and is the most quiet tube amp that I have ever owned. I have gone through a lot of amps over the years. One thing I really enjoy about my SET amp is that I can more easily tell the difference between tubes, cables, and source components. With my OTL amp, the differences were much more subtle. For me, I would not say that OTL is "superior" as that has not been my experience. I would like to re-visit OTL one day, but I am thoroughly enjoying my SET amp so there is no rush.

@thaluza  I think you're overgeneralizing.

https://www.lineartubeaudio.com/products/zotl-40-reference-amplifier

@twoleftears,

No, I am just relating my extensive experience with one brand. I made it clear I have no experience with Tenor and Atmasphere. Nor do I have experience with other brands. The link you provided does not say anything about user experiences with Linear Tube Audio, so it means nothing to me. I take manufacturer's hype with a grain of salt. I would be very interested in reading about what you and others think about LTA, though. As I said, I would like to re-visit OTL one day. Seems like LTA is more like a Berning amp?

Again, I do not know how to measure this or if there is any way to measure this. SETs simply sound more direct. Instruments and voices sounds realistic, as in small, focused, dense and direct. Just the way they sound in real world. This doesn't happen on any of the Push-Pulls. In fact this is the primary sonic difference I was trying to nail between the 2 topologies. A vast majority of the amps therefore do not sound like real thing. Even a large instrument like Cello, when bowed has a very direct and focused sound, like it is speaking to you. Only SETs get this directness. Is it because it just amplifies without any further "processing" ? May be. Whether it is measurable? I don't think so, I have never seen any amps having a measurement which talks about these characteristics.

I have heard SETs with negative feedback (Unison Research) and without (Audio note, wavac, trafomatic, Allnic). The directness is there regardless of feedback and output type. Feedback does make the sound more controlled, sometimes too controlled, affecting the flow. I prefer zero feedback every time.

@pani,
’Even a large instrument like Cello, when bowed has a very direct and focused sound, like it is speaking to you. Only SETs get this directness. Is it because it just amplifies without any further "processing" ? May be.’

Yep! Precisely my same reaction with initial listening exposure to a SET amplifier. In a nutshell,  more real, more natural.   Different people hear and are drawn to various things when listening to music via home audio. There is not a single topology that gets everything right, no perfection. So people resort to choosing what comes closest to sounding ’more’ right than other available alternatives. So it may be SET, OTL, class A solid state, class D or whatever. SET for me and something else for somebody else.
Charles