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

Showing 5 responses by boa2

Scott,
As you you know from our conversations, I know exactly what you mean. While I love the intimacy conveyed from our 4W SET amp/104dB speaker setup--and will not give that up--when I switch over to the 200W SS amp that we use with the same speakers, there is a presence in the dynamics that comes with the increased power. Our 50W triode amps exhibited the same kind of baseline density and ability to respond to musical transitions that eludes the low watt SET's that I've heard. Still, I think it's all about what you want in a system, or perhaps more about the kind of mood that you're in.

As Terry Cain (of Cain & Cain speakers) says so well:
No one amp will keep a man happy long term. You need a young, firm perhaps not too articulate one you can swing from the ceiling with. And you always need a detailed and refined lower power one, the one you will never ever sell. This amp carves out the essence of tone and artistic intent, but cannot satisfy animal musical behavoir due to power limitation. With music, you cannot have too much fun. Don't let the amps get in the way. If amp -A- is complaining or not keeping up with your musical energy, just grab another and keep swinging.
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!
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?