Would You Rather Own A Good SET Amp, Or A Great Push Pull Amp?
Throwing this out there because I would appreciate the viewpoints of the many knowledgeable, and experienced audio people here. I'm really torn about a decision I am considering in this regard. And no, sorry, I cannot name the amps involved. I could lose one or both options if I publicized them here. And honestly, only the tiniest fraction of forum members would ever have listened to even one of these options.
The speakers they would be used with can equally accommodate either of these choices per the designer/manufacturer, who I ran it by.
Your thoughts would be appreciated.
Wolf: I have a SS Musical Fidelity X-A1 that sounds like a really good tube amp, but I need to take it apart and re-apply the heat sink grease before putting it back into action (forgot to do so when repairing a manufacturer's assembly error). Been setting for years as I still need to replace the metric tools stolen from the boot of my car, but now reminded I'm on it right now on Amazon.
DeKay |
@nightfall I’ve yet to hear an SET at any price that could beat a good quality PP tube amplifier. I’ve been investigating SETs since the first started to show up in the early 1990s so I’ve heard quite a lot of them. If your speakers can make bass and if you don’t want to bi-amplfy then you will want to pay attention to this next fact: Most SETs have troubles with bass, since the output transformer has to have a saw cut in its core to reduce DC saturation which otherwise causes a lot of distortion. Sorry if this sounds a bit technical. The output transformer works due to something called inductance. Inductance is what allows a long bit of wire that might have only 200 Ohms resistance to have an impedance of 3000 to 9000 Ohms when wound inside an output transformer. Power tubes used in SETs need that kind of load to work properly. That saw cut I mentioned vastly reduces inductance at low frequencies, which in turn means the load on the tube is much lower too. This is bad for the power tube and causes it to make a lot more distortion while also running hotter. As a result there’s no SET made that can make full power at 20Hz. But there are a good number of PP tube amps that can; there’s no need for that pesky saw cut in a PP output transformer. So let’s imagine that you were considering a powerful 20 Watt SET (that’s a lot of power for an SET BTW). Most SETs, because they don’t use feedback have only about 20-25% usable power before distortion causes them to sound ’dynamic’; IOW above that power level distortion masquerades as dynamics. That is why you read about how ’dynamic’ SETs are but its really just distortion. PP tube amps OTOH have about 90-95% usable power. So in the case of the 20 Watt SET, it would have about 5 Watts of clean power where a 20 Watt PP tube amp would have 18 Watts or so. A PP tube amp of that power is usually a lot less expensive than an SET of that power, probably several times. If the PP tube amp is properly designed and built, by most audiophile metrics it will ’sound’ better than any SET of the same power and likely a lot of SETs with considerably less power. But for PP tube amps 20 Watts is about the golden point where you can get both really wide bandwidth and decently low distortion. A good example of such an amplifier is the Dynaco ST35; if you find one in good condition (there are vintage ones and new ones) you’ll find them causing SETs pain and shame on speakers like the ones you mentioned with no worries. They are rare but there are PP tube amps of even less power- like 5 Watts. Any SET of that power level will fall flat on its face in comparison, if musicality and neutrality (so it can play any kind of music easily) is your goal. Now if you’re stuck on an SET there is hope. If you limit the bass it sees (like 200Hz and above) that will get rid of most of the problems with the bass. You’ll have to bi-amplify of course. FWIW the most successful systems I’ve heard that use SETs take this approach.
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