Running on low power.

I have noticed some tube amps run at around 4watts whereas others run at bout 8.
Would something like this run something like a B&W 601 S3 rated at 88dB/watt?
I understand that on the B&W site, it says that the power handling is 25-100 watts. Does this neccessarily mean that I need 25 watts to get them work properly?

If you only run them at very low levels and don't expect much sound out of them.

When you see that 88db/watt spec it's saying that one watt of power thru them will produce a loudness level of 88db (dunno what frequencies they used) at 1 meter from the speaker. The farther you get from the speaker, the lower the loudness level will be.

For each doubling of power to the speaker, you realize a loudness gain of 3 db. So, assuming one meter from the speaker, you'll have these levels at these powers:

1 watt = 88 db
2 watts = 91 db
4 watts = 93 db
...game over. You're into clipping now and there's not even anything left over for peaks.

Had you more power to play with, it would extend out as such:

8 watts = 96 db
16 watts = 99 db
32 watts = 102 db
64 watts = 105 db
132 watts = 108 db
264 watts = 111 db
528 watts = 114 db

I'm sure you can transpose these numbers to see how a more efficient speaker would play out. Simply start out at the level specified for one watt and for each doubling of power, simply add three db. The benefit of an efficient speaker can readily be seen.

A speaker with an efficiency rating of 91 db would use half the power of this speaker for an equivalent loudness. Likewise, one with a rating of 94 db would require on quarter the power, etc,,,

Now remember, these levels are for listening at on meter from the speaker. Generally the listening position is much farther away from the speaker than that.

Granted, most listeing uses less than on watt on a continious basis, but that extra power is needed for peaks and bass. If you want to play with flea power, you'll need more efficient speakers unless you like the sound of clipping.

I understand the concept of how the loudness adds on.
However, what really confuses me is the power handling spec of 25-100 watts/metre.
Does that mean below 25watts and you're screwed?
I have also read that with every doubling of distance, 6dB is lost. assuming I'm listening from 3-4 metres away, I would be able to extract about 75-80dB with consideration of the peaks. Using a physics text book, this is considered as between a vacuum cleaner and busy traffic. Seriously, I dont know if that's loud enough or not.

BTW, are there any other loudspeakers out there that have higher sensitivity, but better power handling that have similar sound of B&W? I like B&W's warm vocal midrange.

I think what they are trying to say is that less than 25 watts won't do them justice, even at low listening levels. ...but tastes vary. Yours may differ.

Average levels and peak levels are two different animals. For an apparant doubling of loudness, you need about TEN times the power. With that in mind, rethink the math in the above examples, particularly in light of your 6 db distance drop.

As far as the rest, I'll let others add to it. I merely put forth what's considered good, "sound" advice, arrived at from years of experience by others and myself.

YMMV.

You need to look at the characteristics of the speaker and its intended use. Most of your listening is done at less than a watt, with peaks that may hit a couple of watts on really dynamic content, but only for milliseconds. However, with a speaker rated at 86dB (understand that this is probably an optimistic rating at 1kHz), 4 watts isn't going to do very well. If it were 89dB, it would do twice as well, at 92 dB it would do 4 times as well, and at 95dB it would do 8x as well, hence the search for really sensitive speakers if you are a SET kind of guy. It makes all the difference in the world.

What B&W is saying is that they want something with some more headroom, so they are ARBITRARILY setting their low end at 25 watts. That way, you will have decent headroom, essentially what you would have with the 4 watt amplifier into a 94 or 95dB speaker.

Make sense?

What you you guys suggest for an alternative speaker to B&W 601 S3?
Im looking for similar cost and sound, but of course much greater sensitivity.

Generally, one selects the speakers first and then chooses an amp that can drive them.

Quote:

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Originally Posted by 92135011

What you you guys suggest for an alternative speaker to B&W 601 S3?
Im looking for similar cost and sound, but of course much greater sensitivity.

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Get a better amp, not different speakers.

Considering the wattage output you're talking about, it sounds like you've got your heart promised to a SET amp. Besides the obvious power limitation, one of the other and possibly bigger concerns is that the 601 will drop to a 3 ohm load. Your amp isn't going to like this at all. As others have mentioned, you either need to look at different amps or a different set of speakers. If you must stick with your amp, I'd definitely look at something that has a sensitivity rating in the 90+db range like RGA's AN's (although they are considerably more expensive than the 601's). This will limit your choices but that's what you'll need t do if you want a decent amount of volume without clipping your amp. Other speakers with higher sensitivity ratings are PSB, Monitor Audio, Von Schweikert, and most definitely Klipsch (although I don't particularly care for their sound).

Good Luck.

Thanks for the advice guys, I really appreciate it.

Do tubes run badly at low impedence? As topspeed pointed out, the 601s run down to 3ohms.

Tubes have taps out of their transformers to match the impedance of the speaker to the amplifiers outputs. In that situtation, you would use the 4 ohm taps.

Speakers? First thing that came to my mind was Triangle. The Titus is $500 if I recall correctly, and works wonderfully with low power amps. Kevin from Upscale Audio carries the line.

Quote:

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Originally Posted by 92135011

Thanks for the advice guys, I really appreciate it.

Do tubes run badly at low impedence? As topspeed pointed out, the 601s run down to 3ohms.

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No, they don't run badly, they just don't have enough power.

Let's say I stick with the 601s.
I see that norh has a single ended integrated tube rated at 18wpc
What you guys think of this amp? will it drive these speakers?

If not, I'm considering maybe a jolida 302B rated at 50wpc, which should be more than enough.

1 watt = 88 db
2 watts = 91 db
4 watts = 94 db (From this point on, I was 1 db low on all readings)
8 watts = 97 db
16 watts = 100 db ...game over. The 2 additional watts is inaudiable.

You're basically into clipping now and there's nothing left over for peaks.

Had you more power to play with, it would extend out as such:

32 watts = 103 db
64 watts = 106 db
132 watts = 109 db
264 watts = 112 db
528 watts = 115 db

For additional information, please refer to my post that initially referenced this. All following posts should also be re-read as well, Spacemans in particular.

Here's a final hint. You're always better off with more power than not enough. Period...

sorry, maybe i wasnt making it really clear.
I first was gonna get a 40wpc solid state. I found the 40 watter enough for my purposes.
Except, I'm unsure if tubes give me the same power watt per watt since I have heard some people say that you need more tube power to equate solid state.
Then I read some other people who said that tube watts are worth more than solid state ones. judging with 40 wpc, I may get 104dB max. When i was auditioning it, I found 10oclock to be sufficient for normal listening. I figure that it will go to 11 o'clock before it starts distorting.

Sorry for the numerous questions, I'm relatively new to the audio world

Tubes clip too. They just don't sound quite as bad a transistors when they do. But they do clip.

Hey Mark, it seems you have a lot of experience in this field.
Thanks a lot for all your replies.

Does 1 solid state watt = 1 tube amp?
many sites say otherwise

See my previous post.

In this day and age, watts are cheap enough. The more the merrier.

many other sites are simply wishing.

Quote:

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Originally Posted by 92135011

Let's say I stick with the 601s.
I see that norh has a single ended integrated tube rated at 18wpc
What you guys think of this amp? will it drive these speakers?

If not, I'm considering maybe a jolida 302B rated at 50wpc, which should be more than enough.

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Get a good 100 watt SS and be done with it.

Quote:

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Originally Posted by mtrycraft

Get a good 100 watt SS and be done with it.

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I agree. Nothing can substitute for having more power, especially reserve power (Dynamic Headroom) which can reach up to 200 watt.
Tube amplifiers are way over rated, low powered and most of them have high THD% rating.

A watt is a watt, regardless of what is producing it. I'm getting the impression that you are generalizing a lot regarding the sound of tubes vs. ss amps. The difference isn't as dramatic as you may think, although there are definitely differences. If you love the warm (some would say "euphonic") sound of tubes but need enough juice to drive the 601's, it's going to get expensive...very quickly. I hope you're looking used for this. You may find some very neutral to warm sounding ss amps that will suit you needs and drive the 601's better. Plus, they'd be cheaper and you won't have to hassle with biasing or tubes wearing out. Something to consider don'tcha think?

Why don't you find a mach meter to use as your picture :)

Quote:

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Originally Posted by mtrycraft

Why don't you find a mach meter to use as your picture :)

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I'm a gearhead first and foremost but that's not a bad idea at all. I'll have to see what I can find.

Thanks for the tip.

I believe you would be making a big mistake trying to use a low powered SET, with a speaker whose sensitivity is 88 db. I think you would need at least 25 watts per channel to get good sound from your B&W's. The reason why is because of their impedance. B&W's are not the most amp friendly in that respect! If you really want to try a SET, you should find a speaker whose snsitivity is at least 94db. Try Coincident Speaker Technologies, klipsch ( I do not like them), other horns or a lowther type speaker, say from Moth Audio!