Is the a25.2 underpowered? Is your room large? What "more" are you looking for?
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The a25.2 is 50 wpc; the room is 12 x 25 (with two large openings). But I'm not looking for more volume so much as clarity and low-end definition. I can't swing a sub in the room right now (the kids would be climbing on it constantly), but I'd like to in the future, and the a25.2 only has a set of preamp/sub outs. (You helped me figure this out on another thread, Bob; thanks again).
Yeah a Class D 100 watt would rock.I have the Quad 11L but they are self powered.I wish I had the 12L amped version though and w have heard that some prefer passive ones.A small sub would be good to fast and music not HT oriented (Aperion 8S or HSU VTF etc).But that small speaker in that sized room could use more current.
Currently using two PS Audio A-100s in my system. The A-100 uses the same ICE module as the Bel Canto S-300, Cary CAD-1, Rotel and probably many others. The PS Audio anCary amps seem to go for a bit less than the Bel Canto used. If you crack them open and peek at the input board, which is where main the difference is, the Cary and PS Audios look a bit more substantial, IMO. I like the size of the PS Audio units, and they sound good also.
I ran a pair of 12L's with the little Kingrex amp. It sounded wonderful, but obviously not much power, as it was a 10wpc t-amp.
Kingrex has a new 50wpc t-amp power amp for $799. 30 day trial from AudioMagus. I'd look into it.
Or, B&K still makes stereo amps. Upgraded versions of the old classic ST140's and ST202's. If you google you can find them pretty cheap, too.
I've been reading up on the PS Audio A100 and think I'll go with it. I also think I have a better sense of what I'm looking for and wonder whether adding a power amp will help. With my current setup, the sound really opens up at higher volumes. Will a power amp give me this effect--a more open sound and better speed and dynamics--across the full volume range?
Will a power amp give me this effect--a more open sound and better speed and dynamics--across the full volume range?
I don't see how. Your room is fairly large and your speaker is fairly small. Unless you're sitting within a few feet of the speakers, I'll guess the little guys are distorting badly. If you can't do a sub, I'd consider floorstanding speakers with either enough drivers or larger drivers to move a lot more air easily.
For example, Revel Concerta F12
I own LS3/5As which are roughly the same as your speakers, but somewhat higher sensitivity than the 83dB of the LS3/5As. You don't need a lot of power to make these speakers perform as they were designed. Also, they respond well to voltage changes so they are very good with smallish (18-25W) tube amps.
But, as Bob Reynolds suggested, you are asking too much from your amp. It really is best with you sitting 6-8 feet away and the speaker separated by the same amount, pulled at least 1M away from side and back walls. If you do this, you will hear the true glory of these speakers.
The Quad 12L will give you more bass and a more extended treble at the expense of sound staging. It will work better in a bigger room, and so on....up the line
I should clarify, too. The room is relatively large, but the listening position is roughly what Frihed90 described (sitting 10 feet away with the speakers 8 feet apart and the speakers 3 feet out from the wall).
The idea behind my question was whether, given the Quad 11L's 86dB sensitivity, moving from 50 wpc to 100 wpc would get more out of them. Some posts on this thread and others suggest that it would. But now I wonder whether I'm really just looking for reasons to buy a new amp .... Nothing wrong with that, I suppose, but it's not what I intended.
One reason the Quad 11L has an 86dB sensitivity (2.83 volts / 1 meter) is that its woofer doesn't move much air. It'll take a certain voltage across the speaker terminals to generate an adequate SPL at your listening position. It won't matter if the amp can produce 50 watts or 500 watts; the speaker will distort much more and much sooner than the amp. Your speaker position means you get limited boundary reinforcement, so the voltage will have to be higher and the speaker will have to work harder, i.e., more distortion. The bottom line is that the speaker is too small for your room/setup.
The speaker was designed for a much more intimate environment. If you have an SPL meter, use it to determine a typical volume level at your listening position. Then measure again at 1 meter from the speaker without adjusting the volume.
And, of course, you are correct that there is nothing wrong with buying a new more powerful amp. It's just that the speaker will be distorting around 10% (probably below 60 Hz), so if you've saved some small fraction of 1% on the amp side, you still have a problem.
For comparison, here's the specs of the B&W 800D. It has two 10" bass drivers and its distortion is close to 1% (remember that's considered clipping for an amp) at 45 Hz (90 dB, 1 m).
Well, I went ahead with the PS Audio Trio A100. I'm glad I did. I got a good enough deal that I figured I couldn't lose money, and I like what I'm hearing. Improved clarity, detail, and transparency. More bass definition as well; this is the one area where the change has made the limitations of my little speakers clear.
All the feedback was helpful, thanks, and so was this thread: