Low wattage amplifier

[mpompey]

I have a close friend that has recently gotten into low-wattage amps, that supposedly sound better. As far as I'm concerned, electricity is electricity. To me it just sounds like audiophile snake-oil that music/movies will sound better because they are powered by a lower-wattage amp. But my friend swears his system sounds better driven off of a 2 channel Consanance Cyber 100 versus 2 channels off of his B&W 7-channel monster amp.

But is that really the case? Is this just a case of psycho-acoustics or is there something more at work here?

 

[adwilk]

Lower wattage amplifier use means less of a chance of pesky, out of control, electrical waves passing through the brain and diminishing the listening experience. If your amplifier doesn't make your speakers sound like good desserts or scotch taste, you're likely the victim of using way too many watts in your sound system.

 

[j_garcia]

I've heard it before too; low wattage with high sensitivity speakers. I don't see it as being a benefit, but I haven't listened to a setup like that either.

 

[avengineer]

I have a close friend that has recently gotten into low-wattage amps, that supposedly sound better. As far as I'm concerned, electricity is electricity. To me it just sounds like audiophile snake-oil that music/movies will sound better because they are powered by a lower-wattage amp. But my friend swears his system sounds better driven off of a 2 channel Consanance Cyber 100 versus 2 channels off of his B&W 7-channel monster amp.

But is that really the case? Is this just a case of psycho-acoustics or is there something more at work here?

There is a lot at work here, including suggestion. Have a look at the Consanance, then look a the B&W. Which "looks" like it would sound better? Some tube amps, especially the low-watt, low neg feedback types, have relatively high output impedance. And that's just for starters. There are a lot of reasons for them to sound different. "Better" is subjective, and HIGHLY influenced by other non-audio suggestions.

This might be a classic case of, "Do you want to be right or happy?"

 

[Swerd]

Is this just a case of psycho-acoustics or is there something more at work here?

Not so much psychoacoustics as audiophile group-think.

At some audio shows, I ran into demos of flea powered amps (almost always with vacuum tubes putting out 10 watts or less) driving speakers with huge diameter woofers and enormous horn-loaded tweeters. I thought these speakers sounded wrong or flawed, but they were very sensitive allowing them to be driven by amps of very low power. They were very expensive and were for the most part ridiculous looking too. But these rooms were full of adoring audiophiles. I felt like the little boy at the parade of the Naked Emperor, who shouted out "Hey, he's got no clothes on".

I'm not saying that all highly sensitive speakers must sound bad – there may be some that do sound good – but I've never heard them.

As to the idea that very low powered amps do something superior to high powered amps, there is nothing to support that. Most of those flea-powered vacuum tube amps were based on designs that have been around since the 1920s.

I'd sooner argue sound quality with the high sensitivity speaker/flea powered amp fans than I would argue about the benefit or futility of using high-priced speaker cables. Interestingly, such exotic cables are also prominently featured at these same audio shows .

Let your friend enjoy his toys, and you enjoy yours

 

[j_garcia]

What I would expect with a low watt tube amp, even with a super sensitive speaker, would be distortion. Tube amps have funny ways of handling that and I can imagine this likely ends up as a very warm sound that may be pleasing to some.

 

[mtrycrafts]

I have a close friend that has recently gotten into low-wattage amps, that supposedly sound better. As far as I'm concerned, electricity is electricity. To me it just sounds like audiophile snake-oil that music/movies will sound better because they are powered by a lower-wattage amp. But my friend swears his system sounds better driven off of a 2 channel Consanance Cyber 100 versus 2 channels off of his B&W 7-channel monster amp.

But is that really the case? Is this just a case of psycho-acoustics or is there something more at work here?

It was mentioned that low watt amps usually have high output impedance.
This causes the frequency response of the amp to that of the speakers just amplified.
I guess those folks who love them must love the FR of their speakers not being flat

 

[ski2xblack]

I have a close friend that has recently gotten into low-wattage amps, that supposedly sound better. As far as I'm concerned, electricity is electricity. To me it just sounds like audiophile snake-oil that music/movies will sound better because they are powered by a lower-wattage amp. But my friend swears his system sounds better driven off of a 2 channel Consanance Cyber 100 versus 2 channels off of his B&W 7-channel monster amp.

But is that really the case? Is this just a case of psycho-acoustics or is there something more at work here?

There is most likely something going on. For some reality based perspective, your friend should read this. If that Consanance is biased fully into class A, he should read this, and this.

 

[slipperybidness]

Really, it makes no sense to me at all.

You want a high-powered amp. Even for high sensitive speakers, even for low listening levels, etc. A high powered amp will have no problems working at lower levels, and in fact it will most likely be operating in a very linear range of its amplification abilities.

Running a low powered amp, near its limits, you will be running in a non-linear operating range of the amp. Not good, introduces distortion and artifacts to the signal.

Now, on average (RMS), you probably aren't using a whole lot of watts anyway, just for those huge dynamic swings that you really use a lot of watts.

Of course, these are generalities, there may be some outliers or one-off amps that break the mold.

But, for me, requesting a low watt amp is just plain silly. The only way I would ever own one is if I built it myself.

 

[KEW]

What I would expect with a low watt tube amp, even with a super sensitive speaker, would be distortion. Tube amps have funny ways of handling that and I can imagine this likely ends up as a very warm sound that may be pleasing to some.

Agreed.
The low wattage guarantees distortion and the harmonic distortion from tube amps tends to be the odd (numbered) harmonics which are generally pleasing (not to be confused with accurate or realistic).
I would probably enjoy such a rig playing electric guitar music, but if I am listening to acoustic instruments like a trumpet, this "artificial enhancement" would drive me crazy.
Electric guitar players tend to enjoy using tube amps for the same reason.

If you want the music to sound like the artist/engineer intended, stick with solid state and make sure you have the watts to avoid distortion (which is not pleasant on SS gear). The good news is SS watts are inexpensive and trouble-free.

 

[avengineer]

It was mentioned that low watt amps usually have high output impedance.
This causes the frequency response of the amp to that of the speakers just amplified.
I guess those folks who love them must love the FR of their speakers not being flat

That's what I was thinking when I mentioned it. Some people use the flaws of amps or other gear as a filter or equalizer to compliment their other gear. An quick example: You have a speaker that has a bit of a sizzly top end. You put it on a tube rig, the top end cools, so you LOVE tubes. What's happening, really, is the tube rig can't drive the low impedance tweeter, so the high end response drops. You coulda done it with EQ (real EQ) just as well.

But we cannot minimize or ignore the touchy-feely nature of tubes in general. It's a regenerative psychological influence, and a very strong one. Picture if you will: low power tube rig, big horny speakers, and black vinyl revolving while you hold a 12" square piece of artwork. It doesn't get more physical, tactile or visual than that. Whatever you might actually hear is spun severely by the other sensory input. If you put all of that in a closet, and the speakers behind acoustically transparent cloth, and the entire experience is about just the sound, lets just say you won't feel the love as much. Maybe not at all.

When have you seen a modern tube amp that didn't show the tubes? They used put them inside the box in the old days, at least the integrated amps. You couldn't tell them from solid state gear, but what's the fun in that? Today we put the bottles right out where you can enjoy looking at them, all glassy and shiny, and glowing orange. That's just gotta sound good!

By the way, the real low-wattage guys are in the 5 - 10 watt range. Just a little quick math...if you were running two channels, speakers at 90dB/watt/meter, sitting 10' away, you can't even hit realistic listening levels with the 5 watt amp. Max is 90dB SPL, so absolutely NO headroom. Typical AVRs run 120 wpc, that's 14dB more, folks. You have to sit really close to the speakers for those low power amps to be worth anything in terms of raw volume.

 

[j_garcia]

Tube amps don't deal with higher demand like SS though, they are FAR more forgiving as they clip. So a 10W amp may be pushed to distortion but still produce sound levels that seem to exceed its power rating. The resulting sound is not what we would call "accurate", but it does not sound like obvious clipping that you might get with SS gear. In essence, this is the sound that people like from tube amps.

 

[ski2xblack]

Tube amps don't deal with higher demand like SS though, they are FAR more forgiving as they clip. So a 10W amp may be pushed to distortion but still produce sound levels that seem to exceed its power rating. The resulting sound is not what we would call "accurate", but it does not sound like obvious clipping that you might get with SS gear. In essence, this is the sound that people like from tube amps.

Bingo! Well, this, along with the high output impedance (load based non-linearity, which really is less problematic than the guys here would imagine...perhaps more importantly, undamped back emf from the speakers, resulting in ringing and overhang, or worse, microphonic speakers feeding your room's response back at you!). The clipping of a SET amp for example is extremely benign; even and odd harmonics, but in a monotonically decaying pattern that doesn't extend past the 10th harmonic typically. To the ear it acts almost like an ideal compressor, at least until the distortion gets really excessive. Your ears don't recognize the distortion as such. This harmonic embellishment tends to "put the meat on the bones" as the tube guys like to say.

 

[jonnythan]

Tube amps are great for guitars. Not so great for listening to music at home. They do have a rather distinct character though.

 

[wire]

Tube amps are great for guitars. Not so great for listening to music at home. They do have a rather distinct character though.

hehe , I prefer my tube amp to my Bryston 4b and my Carver tfm 35 . The tube amp has 2 power supplys and weights close to my Bryston 4b . Tube amp 38 watts per channel = 50 pounds , most is power supply .

 

[slipperybidness]

hehe , I prefer my tube amp to my Bryston 4b and my Carver tfm 35 . The tube amp has 2 power supplys and weights close to my Bryston 4b . Tube amp 38 watts per channel = 50 pounds , most is power supply .

What tube amp you running? I'm in the final stages of a Dynaco ST-30 clone and it is very similar to your (vague) description. The power transformer alone is about 15lbs

Robust, to say the least.

 

[slipperybidness]

What tube amp you running? I'm in the final stages of a Dynaco ST-30 clone and it is very similar to your (vague) description. The power transformer alone is about 15lbs

Robust, to say the least.

Oops, meant to say ST-70 clone (35 WPC)

 

[avengineer]

Tube amps don't deal with higher demand like SS though, they are FAR more forgiving as they clip. So a 10W amp may be pushed to distortion but still produce sound levels that seem to exceed its power rating. The resulting sound is not what we would call "accurate", but it does not sound like obvious clipping that you might get with SS gear. In essence, this is the sound that people like from tube amps.

True in general, but really depends on the specific design. It's possible (and it has been done) to design a SS amp with tube clip characteristics and tube-like output impedance. Not actually all that hard to do, but it by definition lowers the maximum output power spec, so generally not attractive marketing-wise to do it. Conversely, you can design a low output Z tube amp, but again, not usually done because...well, then it sounds to SS-ish.

Most of the sound character attributed to tubes isn't really the tubes but the total circuit design and the compromises that need to be made to make the thing. Same is true for SS. There are subtle tube-only characteristics, particularly in terms of non-linearity, but that's actually secondary and much less audible. When people build low power tube circuits with mushy overload characteristics, it's a deliberate usage of performance flaws as a sonic signature. There are, for example, tube instrument preamps that run their tubes starving for plate voltage, way below spec, because of the distortion that causes. If distortion is the goal, tube circuits give you more chances to achieve it.

Point is, you CAN build clean low Z SS-sounding tube amps, but why would you if people actually want to hear all that THD and IMD when it's driven hard, and the wild response variations with output transformers and high output Z? You CAN build tube-sounding SS amps, and that has been done, but again, what's the point if that's not what people expect or want? It's a self-reinforcing design circle.

 

[cpp]

Tube amps are great for guitars. Not so great for listening to music at home. They do have a rather distinct character though.

I happen to like my audio tube amp and my SS amp, but I do like my 64 Fender Vibrolux Reverb blackface, ( original)

I guess it all depends on the sound you want and not what someone else thinks or wants. It's all about the sound.

 

[Irvrobinson]

The clipping of a SET amp for example is extremely benign; even and odd harmonics, but in a monotonically decaying pattern that doesn't extend past the 10th harmonic typically. To the ear it acts almost like an ideal compressor, at least until the distortion gets really excessive. Your ears don't recognize the distortion as such. This harmonic embellishment tends to "put the meat on the bones" as the tube guys like to say.

You hit the nail on the head. It isn't so much the low power that these audiophiles crave, it is the single-ended tube topology that results in low output power, and especially low current levels into low impedance speakers. And the nature of a SET's output stage makes them strongly interact with a particular speaker's load, so they do sound very different. For some people the ultimate system is vinyl and single-ended tube amplifiers, coupled with horn speakers. Not my cup of tea at all, but at least they're not harming anyone with their alien ways.