Horns + tube amps: can they handle LOUD like SS?


I was inspired by the SET thread currently running, but
wanted to take the thread in a different direction without
disrupting the original.

FYI, my history is all SS... but do I run 2 sets of high-
efficiency Klipsch speakers: La Scalas (104db, 8ohm) +
Forte II's (99db, 8ohm).

That said, I've read countless statements that SET/horns
are just the milk and honey. Sam Tellig for one raves
about small-wattage (any given day he probably mentions
something from 3.5 to 8 watts) SET amps and horns in
glorious harmony.

I haven't heard that combo myself - but I always notice
the caveat that even with high-efficiency speakers, there
is something missing about ability to play loud (there is
always the hedge that "subjective sound is louder"... ok,
sure... but what about the real, honest limits to the
power output?)

I've heard clipping from 100w SS amps into an easy 104db
8ohm load during heavy passages... (no, I'm still not
deaf) - this could be an effect of the particular impedance
curve of the speakers, but that's irrelevent - if 100w
of SS can't muscle it, how can a 3.5-8w SET amp?

Some of us (metalheads, not Patricia Barberheads), listen
to horns for their unmatchable ability to present a live
and engaging experience, with transient response that's
faster than a steel trap. Others love the lush, effortless
nature of the midrange and sweet highs when paired with
tubes... the later seem to be the majority.

I currently run a 200w MOSFET CJ amp into my Klipsch
La Scalas, and am more than happy... they can both sing
and bruise as called for. Can a SET/horn combo deliver
the same? Do other tube amp designs make more sense?
What about push/pull, pentode, etc...

How did Ritchie Blackmore, Leslie West, Tony Iommi
et al. rip the doors off in the 70's? Probably not
on SET guitar amps!

I've been eager to try some tubes with these horns, but
even with the efficiency, it's taking me more than 100w
of SS power to deliver the experience I want with the
proper control. What tube designs/philosophies can
go there?

Obviously, I am no tube pro. Any primer fodder that
you offer won't offend. I've seen a little, but not
enough.

Thanks for your thoughts!
mwilson
The music you like and your preferred playback volume levels mitigate against going low-power SET. Ultimate purity of harmonic structure is not as important a factor for replay of hard rock music as are high-volume capability, full frequency range, and dynamic slam and control. Having said that, I'm betting that the "100w" SS amp you heard distort into the Klipschs before wasn't a high-end piece with a sturdy power supply. On those speakers, a quality 100w piece, be it tube or SS, should certainly not give up before you do (or the speaker does). Since you say you are "happy as can be" with the SS C-J amp that's in your system already, hold on to it. If you experiment for curiousity's sake, you probably will hear a difference with a tube amp, but not because of the way it clips (if you select it correctly). Rather, the overall presentation may take on a somewhat different character than what you're used to, maybe spatially as well as tonally, but it'll be up to you to choose which is preferrable. Even efficient speakers with large woofers need some amp power to get a handle on the bass, so if you audition something tube-wise, I would suggest a push-pull tetrode or pentode design of around 80w minimum or up (VTL makes some nice sounding stuff with high power for the $).

About the guitar amp points raised above, I just thought, as a guitar player, that I might comment. It's true that most stuff in the HM/hard rock genres made since the late-60's has been played through tube amps (particularly Marshalls and their derivatives, themselves derived from the older original Fender Bassman design of the 50's) with anywhere from 50 to 200 rated watts per amp head - with multiple "stacks" prevelant, meaning many heads working simultaneously to achieve a very high-volume "wall of sound". But it's also important to realize that this choice has mostly to do with the sound of an amp's distortion - not how loudly it can play and stay clean. Since the harmonic structure of a tube amp run in clipping produces distortion that is musically consonant, whereas a SS amp's is not, tube guitar amps have remained the popular choice for their characteristic distortion sound, not their volume capability per se. (This explains why, in a recording studio situation where high absolute volume is not necessary to get a sound into the mic and on tape, small tube amps that distort easily at lower volumes have long been popular. Although Led Zeppelin was known for Jimmy Page's Marshall stacks onstage, he often recorded in the studio with tiny vintage Fender and Supro amps, good for only a few watts.) Since in hi-fi reproduction we don't want any clipping to occur (or even come close to it, ideally), the character of an amp's overdriven sound should not be the issue.

P.S. Rats - NOW I see that Sean has beaten me to the "Submit" button...
Thanks for all the insightful follow-ups and recommendations. I am indeed interested in trying a tube amp out of pure curiosity, just wanted a rough idea where to start. As for the Carver white paper, I bet it'll be easier to understand than the 70's Radio Shack/Texas Instruments "beginners" guide to transistors I've been chewing on.

Thanks all for your help!
mwilson

ps: the 100w amp that couldn't was a B&K ST140, I have no problems with it paired with some Wharfedale towers in the basement
ps2: Sean - you know what recording actually sounded best on this system? Elton John on vinyl! Sadly, much heavy rock suffers from poor recording, as you seem to know.
MWilson please don't let these guys talk you into tubes. I tried them with my Klipsch & was very diasppointed, & this was with highly regarded Sonic Frontiers & VTL equipment, not some cheap imitataions. Hot, noisy, microphonic, expensive, high maintenance.
100 watts isn't enough for me either, I prefer about 200 honest w/ch for best woofer control & plenty of clean headroom when playing at the higher levels. Even the super clean & tubelike Ayre V3 @100w/ch just wasn't enough power. But I've always gone back to mosfets for my horns.