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Myth: low-power high-efficiency

The past 6 - 8 months I have been living with very efficient speakers (~ 109dB/m/w) driven by low-power SET amps. The amps use 300B output tubes for about 7 wpc. On paper, this should be a match made in heaven. In fact, the combination is capable of wonderful nuance, subtley, harmonic richness, and tonality. It is really pleasing, especially on chamber and jazz music. Except for one thing - dynamic energy. I am not referring to loudness. It can deliver more undistorted volume than I care to listen to. I'm referring to immediacy, presence, power, and punch - the life of the music. If you go to the symphony, or live blues, than you know what I am talking about. Next week I'm taking delivery of a 90wpc PP amp, to audition in place of the SET. I need an amp that can maintain the purity of tone and harmonic texture of the SET, while delivering more power, to grab hold and take control the 15" bass driver in my horns.

I searched the archives, but have not found a similar post. Are there any other high-efficiency low-power people who moved to a higher power amp? Are you satisfied now?

Scott
skushino
boa2's avatar
boa2
1,557 posts
 
Different tube amps can sound quite different and from descriptions the 300b is NOT the most immediate and punchy sounding tube.
Rene, the 300B might be a tube you'll want to hear at some point. Aside from its enveloping, holographic nature, this tube in certain amps will drive quite well, and give you considerably deeper and punchier bass than will the 2A3, especially when the amp is SS rectified. Naturally, the synergy between the amp & speakers still reigns, so we must consider this first.

Please excuse the plug here, but for vintage Klipsch owners, these are the ticket to maximizing dynamics should you be running a low-wattage amp. Frankly, nothing has been a bigger upgrade in our system than to go to these crossovers, as they essentially 'lighten the load' on the amps, so now they can drive the speakers with a MUCH, MUCH fuller sound, and far greater dynamic presentation. I suspect that with crossover modifications (or the use of an autoformer), some other low-watt/hi-eff combinations could also improve dramatically. Either that, or bi-amp with a PP or SS on bottom, and a SET amp on top. Hmmmm....yummy!
gunbei
2,327 posts
 
In search of the "goods" from both approaches, I'm currently using a high powered SET by Bel Canto, the SET40, with a pair of ProAc 2.5s. I realize I won't have the extreme bliss of either approach, but this combo satisfies my "in-betweener" fetish. I also keep around a solid state BAT VK200 for when the urge strikes. Happy, but open to experimentation.
marakanetz's avatar
marakanetz
5,473 posts
 
To my understanding the high-power and high-efficiency isn't a successfull combo.
Higher powered amplifier may deliver a noise that would be non-negligable through high-efficiency speakers.
owl's avatar
owl
139 posts
 
Scott

Intriguing development, please keep us informed of what you find. Very curious which PP amp have you decided to go with? I also second the idea of having multiple amps available to drop into the system. I've found that to be one way around the conundrum.
boa2's avatar
boa2
1,557 posts
 
Higher powered amplifier may deliver a noise that would be non-negligable through high-efficiency speakers.
We have a 200W McIntosh SS amp running with 104dB Klipschorns, and even with a tube preamp we get no noise at all. In other words, it works beautifully.

Happy, but open to experimentation.
Are we still talking audio here, Dean?
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