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Enough SET Power for Rock and Roll

I'm still trying to figure out what SET amp would sound best for Rock and Roll (and other music but especially Rock) on Klipsch Cornwall II speakers (101dB efficiency) in a room about 18x13 (with kind of medium acoustics - not live, not totally dead.) On a Marantz 2230 (which sounds very good, surprisingly good for being ~35 years old and 30 watts of solid state) I found that when I crank up the Rock and Roll on the Cornwalls I'm listening from about 89dB to 97db, but frankly if I wasn't worried about clipping or blowing out the speakers or receiver I could probably enjoy an occassional 100 dB :) - but if I have to live at 97 dB and below I could. (Measurements made with a Radio Shack meter set on fast, C weighting - taken from 1 meter away from the speakers, and also at the main seating position which is about 10-11 feet from the speaker plane.)

From many posts here and over on AudioAsylum it sounds like a 45 SET amp would sound great but might not have enough oomph - although that isn't 100% certain. It seems that a 2A3 SET amp would have a better chance of handling the loud music and the "complexities?" of Rock (and orchestra music) vs. say simple instrumentals and vocals. Next up would be a 300B SET, more power but some people seem to think it gives away some of the "magic" of the 2A3 and especially the 45. It isn't so clear to me from reading the various posts how any of these tube types do on the low end; I think low end (reasonably deep and tight) is needed to do Rock and Roll well - but so is good midrange and highs, so it's a balance, of course.

What do you think, more power and listen loud with ease, ie go with a 300B, or can a 2A3 or possibly a 45 do it all? Or is it possible that SET just can't do Rock and Roll seriously with 101db speakers in a 18x13 rom? In which case, next up is what kind of tube amp? If SET makes sense, I'd like to give it a try but I don't want to push physics or the budget too hard with experiments that aren't likely to work.

Thanks!
hi_hifi
mapman's avatar
mapman
21,850 posts
 
I wonder what pairings of SET and speaker might do rock/pop best?

Klipsch Cornwall seems like a good match. Are there better ones? What kind of cost should one expect between amp and speakers to really do it well along the lines Larryi described? Any good smaller speaker options?
atmasphere's avatar
atmasphere
11,590 posts
 
I had a set (pardon the pun) of SET 45s. My speakers are 98 db. There was no-where near enough power...

So I built up a set of type 45 push-pull amps just for fun. Instead of about 3/4 watt, now I get something more like 5. So about double what I got out of my 2A3 SETs that I also had. One thing is for sure: the P-P 45s sound a lot better than either SET did before, regardless of volume- deeper bass, more extended highs, far more neutral and engaging in the midrange (nevertheless my 30-watt OTL took it to task immediately but that is another story).

DHT (Directly Heated Triodes) have a lot of linearity, but I don't see people comparing P-P to SET much in this realm, mostly because P-P DHT amps are somewhat rare. But I would consider it- you always want the amp to have essentially unlimited power regardless of the speaker for best result. With the Klipsch (depending on the room) that might mean 15-30 watts to really never be pushing the amp hard.

The problem with SETs is if you need power, the more power the amp can make the more the bandwidth is limited. By the time you get to 7 watts, most of them don't have much bandwidth below 30Hz (if they do then there will be no really high frequency extension...). This means that there will be colorations translating to lack of impact up to about 300Hz. But getting well below 15 or 20 Hz is no problem for a P-P amp, even if it makes 60 watts (and you can still have the HF bandwidth).

Now usually SETs are more transparent than many P-P amps, but if we are to compare apples to apples that P-P amp really should be using DHTs. If its a pentode amp *of course* the triode amp is going to be more linear...

The nice thing here is that with the Klipsch you pretty well can run whatever you want- its friendly to all known amplifiers.
rockadanny
1,221 posts
 
My Audio Mirror SET monoblocks are rated at 45w - plenty 'o power for you. He also makes them at 20w.
larryi
3,719 posts
 
I own a DHT pushpull amp that uses the 45 tube. It is a terrific amp--bass is tight and punchy, harmonic structure of instruments is fully saturated and realistic, and attack and decay of notes is very natural. These are all the qualities one would expect of DHT tubes. The biggest difference with SET amps is in soundstaging. SET amps tend to be better at presenting a big, enveloping soundstage in which the listener feels fully emersed rather than looking from outside in.

I mentioned high quality SET amp in my earlier post because there is a general impression that SET amps are lower in cost because of their simplicity. The problem with that assumption is that it is quite challenging to make decent output transformers for SET amps because of the high DC current saturating the core. The transformer is the key to a great SET amp, and good ones are not cheap.
mapman's avatar
mapman
21,850 posts
 
The Audio Mirror stuff is very nice looking and appears reasonably priced.
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