[tisb0b]

I've searched and found no answers so here I am. I've noticed that a lot of audiophile grade speaker amps seem to have rather low wattage numbers. Take the Leben CS300XS for example its output is only rated for 2x15W and yet costs 3k. My NAD C370 is rated for 120W and only set me back $400. What exactly is the appeal of an expensive low wattage amp over a cheaper higher wattage amp? Because one would think that if you were spending 3k on a speaker amp that you would want it to be able to drive any speakers you threw at it and not run out of juice. The majority of what I've read indicates that speaker amps in general make little difference and considering I've never really noticed much of a difference between headphone amps I am inclined to believe it. I'm sure I'm overlooking something in this equation but I have no idea what. 

 

[aRRR]

Amount of wattage and sonic bliss have nothing to do with each other. You just need the right kind of speaker for your amplifier (Or is it the other way around?) Either way, concerning low power amps; you are correct that you will be limited to a certain amount of (high efficient) speakers, it is just that some people just love tubes.

 
Oh and there definitely is a difference between amplifiers, both speaker and headphone wise.

 

[Clarkmc2]

Some of the best amplifier designers have found that it is very, very difficult to design a higher power amp with the same ultra high fidelity as their best low power efforts. Usually not possible. It is not just tubes. Nelson Pass has designed and built his FirstWatt power amps to a higher fidelity than his larger PassLabs pieces. Both are the best he can do given the requirements of each line.

 

[RexAeterna]

wattage means jack when it comes to speakers and amps. i'm being serious. wattage has nothing to do with the speakers or amp sonic   charaters. it has to do more to the stereos  curcuit tapelogy design within the schematics. for speakers it varies from crossover design,cabniet resonunce,dispersion,room acoustics,frequency reflection,ect.

 wattage for speakers it comes down to senstivity@1w@1m. a good sensitive speaker will hit 92db@1w@1m. rest of the wattage gets dissipated as heat in both the amp and speaker. unless you need rock concert ear damaging levels you really don't need anymore then 30-50w maybe depending on the room size. most speaker wattage listed is it's maximum wattage it can sustained short time(few seconds to couple minutes if lucky) before it blows. other measure wattage at certain frequency range(1khz). some measure till distortion takes place. unless the speaker is very very heavy and very very expensive(there is seriously speakers out there that weigh over 200lbs per speaker!) you should always take watts with grain of salt.
Quote:

I've searched and found no answers so here I am. I've noticed that a lot of audiophile grade speaker amps seem to have rather low wattage numbers. Take the Leben CS300XS for example its output is only rated for 2x15W and yet costs 3k. My NAD C370 is rated for 120W and only set me back $400. What exactly is the appeal of an expensive low wattage amp over a cheaper higher wattage amp? Because one would think that if you were spending 3k on a speaker amp that you would want it to be able to drive any speakers you threw at it and not run out of juice. The majority of what I've read indicates that speaker amps in general make little difference and considering I've never really noticed much of a difference between headphone amps I am inclined to believe it. I'm sure I'm overlooking something in this equation but I have no idea what. 

 

 

[tisb0b]

Interestings thanks for the responses so far. 

 

[JRG1990]

Watts only account for spl you can use this calculator to calculate the spl of your set-up http://myhometheater.homestead.com/splcalculator.html .
 
As to whether there is a huge difference in speaker amps a interesting blind test was done here http://www.matrixhifi.com/ENG_contenedor_ppec.htm 
 
Your money is better spend on a good pair of speakers.

 

[Uncle Erik]

First, figure out which speakers you want. Then buy an amp to match them.

Some speakers, like horns and singledrivers are highly efficient. You can drive them well with a fleawatt amp under 10W or so. The low power amps have a lot of advantages - you can run tubes and devices that don't scale to high power well and have unique (and gorgeous) sound signatures. Other speakers, like Magnepans and Apogees, need plenty of grunt power.

Speakers are much more important to the sound than an amp is. Choose your speakers first, then find a good amp to drive them.

One last thing - power ratings can be fudged in any manner of ways. Don't pay attention to a manufacturer's claims for power.

 

[Larry I]

I agree with the posts above.  I agree that that, as long as the speaker is appropriate, lower powered amps operating within their comfort zone tend to sound better than higher powered amps.  To me, this is particularly the case with tube amps.  I am a tube amplification fan, though I tend NOT to like high powered tube gear that uses a whole lot of tubes to achieve high power (particularly pentode designs with a lot of negative feedback).  Solid state gear that is scaled up to achieve higher power also suffer sonically, but, not as dramatically as high powered tube stuff.  For higher powered tube designs, I like OTL amps, but, these really work best with speakers that have a high and flat impedance curve.
 
I find that most people overestimate the amount of power they really need.  Even if I owned somewhat inefficient speakers (which I don't), and needed a lot of power to achieve wall shaking volume, I would much rather scale back my volume demand if it meant having to use a really high powered amp that did not sound good at lower volume.  The VAST majority of the time, even with inefficient speakers, less than a watt of power is being used.
 
I have fairly high efficiency speakers (99 db/w) which I drive with a parallel single-ended amp (two 2a3s per channel).  I really like this combination.  I've also driven my speakers with a range of other amps, with petty good results (I also own, and like a pushpull amp using 45 tubes).  The best I've heard on my system from solid state was a fairly low-powered First Watt J2 amp.  This was not as good as my parallel SET amp, but, then again, it is a whole lot cheaper.

 

[Clarkmc2]

Quote:

 
 
I find that most people overestimate the amount of power they really need.

I have fairly high efficiency speakers (99 db/w) which I drive with a parallel single-ended amp (two 2a3s per channel).  I really like this combination.  I've also driven my speakers with a range of other amps, with petty good results (I also own, and like a pushpull amp using 45 tubes).  The best I've heard on my system from solid state was a fairly low-powered First Watt J2 amp.  This was not as good as my parallel SET amp, but, then again, it is a whole lot cheaper.

The overestimation of power needs probably dates from an old JBL paper warning of clipping damage to transducers used with low power amps. No coincidence that it was authored after the advent of bipolar transistor audio amplifiers. Users of well designed tube, MOSFET and JFET amps need not worry. Even badly designed tube amps can not go DC or clip to abrupt waveforms. As soon as a bipolar amp gets out of its comfort zone it can kill at least tweeters. A little more and it will fry large voice coils. Or dynamic headphones.
 
Another advantage for me in using low powered amps is avoiding the death grip high damping factor large amps have on woofers and full range drivers. In my experience most amps control woofers too tightly. Having extensively tried both, I feel it sounds more natural to use moderate damping factors.
 
If your high efficiency speakers are full range drivers, try the FirstWatt F2 JFET. It will sound much better than the J2.  I believe it costs something like half what the J2 does.
 

 

 

[DeadEars]

You've had some good answers here.  I think the best advice is to focus on the speaker/amp match.  If you've got neither, then buy them based on finding people who are highly experienced with combinations.  This is especially true with low-wattage amplifiers, where the speakers can make or break the success of the system.
 
For instance, I'm currently building a pair of OTL amplifiers based on the Atma-Sphere M60 design (circlotron).  These amplifiers are fully balanced, dual-differential triode amplifiers where the speakers are hooked up directly to the output of the tubes with NO output transformers.  Unfortunately, they do not sound very good with speakers that have low impedence, especially if the impedence curves over the frequency spectrum are uneven, or drop below 4 ohms at some frequencies.  OTOH, with 16 ohm speakers they can sound divine!  I heard them with a pair of high-efficiency wave-drive horns (Audiokinesis PlanetarIum Beta's) and was totally blown away by how REAL the music sounded.  I could reach out and inspect Norah Jones' tonsils.  But the same amplifiers powering a pair of PSB speakers sounded very average, and uninvolving.
 
Some of the really great pairings I have heard and spent lots of time with include:
* McIntosh MC225 (25 watts per channel) paired with original Quad 57 electrostatic speakers
* McCormick DNA amplifiers (250 watts per channel) paired with Vandersteen 3a dynamic speakers
* Airtight tube amps (high power) paired with SoundLab A1 electrostatic speakers
* McIntosh MC2102 tube amps (100wpc) paired with Joseph Audio small towers -- don't remember the model
* Sandersound Magtech (300wpc) paired with Magneplanar 3.6 speakers
* Atma-Sphere S30 (30wpc) paired with Audiokinesis Jazz Module speakers
 
Of course this is based on my criteria for good sound, which probably differ from yours.  But most of these represent concensus viewpoints among owners.  Watts seem to have very little to do with the "goodness" of the results.  But synergies between power transfer functions of the amp and speaker sensitivities at different frequencies have a LOT to do with the quality.
 
Hope this helps!
 
Frank
 

 

[tisb0b]

I am appreciative of all the responses in this thread so far and now I feel a little bit more informed =)
Quote:

You've had some good answers here.  I think the best advice is to focus on the speaker/amp match.  If you've got neither, then buy them based on finding people who are highly experienced with combinations.  This is especially true with low-wattage amplifiers, where the speakers can make or break the success of the system.
 
For instance, I'm currently building a pair of OTL amplifiers based on the Atma-Sphere M60 design (circlotron).  These amplifiers are fully balanced, dual-differential triode amplifiers where the speakers are hooked up directly to the output of the tubes with NO output transformers.  Unfortunately, they do not sound very good with speakers that have low impedence, especially if the impedence curves over the frequency spectrum are uneven, or drop below 4 ohms at some frequencies.  OTOH, with 16 ohm speakers they can sound divine!  I heard them with a pair of high-efficiency wave-drive horns (Audiokinesis PlanetarIum Beta's) and was totally blown away by how REAL the music sounded.  I could reach out and inspect Norah Jones' tonsils.  But the same amplifiers powering a pair of PSB speakers sounded very average, and uninvolving.
 
Hope this helps!
 
Frank
 

 

 

[twylight]

For higher power, modern solid state amps - the overhead of the transformers and dampening factor seems to set the amps apart.  Receiver amps are fairly pathetic if you have decent speakers that are in the ~90s to drive.  A good multichannel amp not in the "LOL WAT?" price range is ATI.  Lower end than that is the Emotiva XPA line.  I am very unimpressed with ICE amps and could easily pick them out versus a 1805 ATI.
 
I really love a tube somewhere - I tend to get it in the preamp or DAC phase.
 
Room treatments are the most important upgrade for speakers - if you are spending money anywhere else you are missing the best bang for buck upgrade out there.  Even just a few reflection traps will make a HUUUUUUUUUUUUUUGE difference at your primary listening positions.   Dont be fooled, every speaker is tossing reflected waves all over the place (normal, dipole, bipole, near field, etc) and some treatments make a really big difference.
 
Treated Room > Speaker > Source > Amp > cables
 
The first room you treat will forever put it on the top of your list of things to do for audio.
 
Another reason wattage doesnt do alot is you have to double the wattage to gain 3db of volume. (napkin math)  So depending on your final volume level you are looking for in a certain room - efficient speakers at 85db is pretty easy to reach...7 inefficient speakers at 110 db is very challenging to reach, especially in a larger room.  The cone of sound a speaker makes decays as it travels.
 
Also as noted by others - wattage ratings are pure lies - just buy something with a good return policy and try it out - AFTER you have treated 1st reflections.

 

[JRG1990]

What is a good damping factor? I undertstand it's the amps control over the woofer but what is a good value, my amp is 280 @ 400hz is that good?.

 

[mulveling]

I've used a wide range of amplification, from 20W vintage tubes to 600+W solid state. I've been back-and-forth on the issue of how much power is really needed. I currently use 250 W/ch tube amps. 
 
While I can agree that 20-30W into an efficient speaker (say 93dB/Watt) will run you out of the room with most rock/pop recordings, there's a huge advantage to the higher power levels for high dynamic range recordings at stout listening levels. My speakers are 93dB/Watt and I sit reasonably close (8ft); with rock I was able to crank it as much as I liked with a pair of 25W/ch Heathkit W5. On the other hand, I (by accident) evoked hard clipping on a 70W/ch tube amp when listening to Sheffield Labs' recording of Firebird Suit (direct to disc) for the first time. Yes, it was very loud, however it was a bass-heavy transient that wouldn't have been unpleasant - I would have loved to hear the same without the clipping (and now I can, but to be honest that recording does make me a bit nervous). Also, by the time you hear hard clipping on a tube amp you're a ways beyond soft clipping, which already compromises the signal. Thinking back a bit more, I'd also heard some light clipping on a 35W/ch tube amp with stuff that was well recorded, though not as crazy as that Sheffield Labs album. I DID notice the jump from the 35W amp to the 70W in terms of headroom. Some people say 3dB isn't a lot - no it's not night and day, but it is SIGNIFICANTLY noticeable, and if you're into hifi then you should care about that. Also note that if you sit kinda far away in a large-ish room with monopole speakers, then that requires gobs more power versus sitting close-ish in a smaller room. It can be easy to underestimate your power needs.
 
So there's something to be said for having plenty of headroom, as long as you have recordings with some decent dynamic range. My 250W monoblocks remain clean and crystal cear at any humane level. Now if you always keep the listening level neighbor friendly, then yes - I don't think there's much point to the higher power amps. I don't have neighbors in the traditional sense
 
That said, there is a special warm sound to those low/medium power vintage amps that is kinda special - that's why I was obsessed with them for a while. I never got around to trying the low powert SET stuff - that's just not going to cut it for my needs. 
 
...and that 600W SS amp I had years ago sounded awful at any level

 

[Clarkmc2]

Quote:

What is a good damping factor? I undertstand it's the amps control over the woofer but what is a good value, my amp is 280 @ 400hz is that good?.

That depends on a lot of things, including your listening preferences and the speakers you will use. When the FirstWatt F1 and F2 were designed, for full range speakers, the question was whether you wanted less or more than a factor of 0.5. That is zero point five, as compared to your 280.0.
 
Your amp might be just the ticket for some speakers. With anything I use here, including some 18 inch hifi woofers in huge JBL studio monitors, it would suck the life out of the bass as far as I am concerned. But others prefer the sound of a big amp I have with a factor of over 800.
 
I think that 400hz is kind of high for evaluating damping factor. I would be more interested in how the control is at larger excursions seen at lower frequencies and higher power.
 
And yes, room treatment - if using speakers - is the best spent money. I don't want to hear any more about caps, wire, balanced, or DACS from any speaker listeners who have not improved their room acoustics. They priorities are so misguided I would not bother to pay attention to what they say. It is like new wax on a car that has a blown engine.