So it turns out 8 watts is enough

[naimnut]

I finally ran across a used 300B amplifier at a fairly reasonable price. Single-ended, no negative feedback, class A. It sounds amazing with my 93dB efficient speakers but also sounds really good with my Quad 2805s, as long as I don't try to crank it too loud.

This experience has taught me that much of my listening takes place below one watt.

 

[lordmortlock]

It’s always been more important to me that a system sounds good playing quietly, rather than loud.

 

[Tony L]

This experience has taught me that much of my listening takes place below one watt.

It does with most people & systems and is actually pretty easy to calculate if you have an accurate sensitivity figure for the speaker. If we take 83db for a Watt at one metre as an example as many speakers are around this (ESL57, LS3/5As, JR149s etc) that is the starting point. You get an extra 3db for having two speakers in the room, though lose 3db for every metre over 1 to the listening seat. Every doubling of amplifier power adds 3db. This gives us:

1 Watt: 86db
2 Watts: 89db
4 Watts: 92db
8 Watts: 95db
16 Watts: 99db

Again subtract for listening distance. Plus you can add another 3db or more if the speaker is wall-proximity or corner-loaded. I’m assuming free-space in the examples above. All things being equal if your median listening level is in the 76-80db or so a good 8-10 Watt amp has sufficient reserve to handle transients up to 95 db or so, and that’s likely all you’ll need (actually a lot less than that on rock/pop).

Obviously it is not quite that simple as we have impedance and reactive loads to contend with too. I have to admit I’m surprised you are getting good results with ESL63 type speakers and 300Bs as they have quite a variable load. I’m assuming you have something with seriously good output transformers!

I actually hooked a peak-reading meter and an oscilloscope to my Stereo 20 to try and get a better handle on what I’m actually asking of it into my JR149s (and by implication LS3/5As) rather than just applying the theory above. I’m in range, hitting about 8 Watts on transients if listening at the very loudest I’d ever want to listen. This on the 16 Ohm tap. I just wanted to make establish my math was ok and I wasn’t clipping the amp, it certainly sounds superb!

 

[Big Tabs]

math

 

[JTC]

Likewise, I expect most of my listening is well under 1w. Probably well under 0.1w. I do find, though, that with my speakers, lower level listening reduces the perceived balance of bass:mid:treble in the sound, and I’m finding the (ostensibly sacrilegious) loudness control on my amp very useful indeed.

 

[Tony L]

Likewise, I expect most of my listening is well under 1w. Probably well under 0.1w. I do find, though, that with my speakers, lower level listening reduces the perceived balance of bass:mid:treble in the sound, and I’m finding the (ostensibly sacrilegious) loudness control on my amp very useful indeed.

I tend to do this with room positioning, system balance etc. My Lockwoods are positioned where they sound right at the levels I listen. They sound a bit overblown in the bass at louder levels, which is of no concern to me as I never crank them up. I am only ever interested in getting kit to work within my desired volume envelope, what it does outside that range is absolutely irrelevant to me. If a system sounds right at a median level of between 75-80db at the listening seat that’s me done!

PS I suspect most little speakers have some of this designed-in to some degree as they are clearly not designed for/not capable of high volume. I’ve always viewed about 80db median as about the absolute limit for a mini-monitor with a 5-6” bass mid. If more level is required then it is bigger speaker time IMO.

 

[Darth Vader]

Likewise, I expect most of my listening is well under 1w. Probably well under 0.1w. I do find, though, that with my speakers, lower level listening reduces the perceived balance of bass:mid:treble in the sound, and I’m finding the (ostensibly sacrilegious) loudness control on my amp very useful indeed.

This is due to the way the ear perceives sound at low-levels. The loudness control tries to counteract this loss at low volumes and flatten the curve to something like you'd have at a normal volume.

Take a look here http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/earcrv.html#c1

Cheers,

DV

 

[Chris81]

I tend to do this with room positioning, system balance etc. My Lockwoods are positioned where they sound right at the levels I listen. They sound a bit overblown in the bass at louder levels, which is of no concern to me as I never crank them up. I am only ever interested in getting kit to work within my desired volume envelope, what it does outside that range is absolutely irrelevant to me. If a system sounds right at a median level of between 75-80db at the listening seat that’s me done!

That makes absolut sense in my eyes, we (as you know I guess) don't have a linear hearing system and as lower the loudness is as less sensitive we are to bass frequencies. A speaker in a room with a +6dB bass bump at 80dB can be perceived as linear while turning the volume up to 90dB it can be "too much bass".

Therefor a linear frequency response in the bass frequencies is not in every case the best solution. It will always depend on the interaction of the room and the most used listening volume IMO.

 

[SteveG]

My Audio Note Oto is only something like 9W per channel but really doesn't sound like it. In fact it's sounds more powerful than most amps I've used.

Sadly the issue I've had with it is nothing to do with sound quality but more that its been very unreliable. It's put me off valve amps to be honest.

 

[JTC]

This is due to the way the ear perceives sound at low-levels. The loudness control tries to counteract this loss at low volumes and flatten the curve to something like you'd have at a normal

Indeed. I also tend to find treble perception drops off too, but they don’t mention that in the article. Could just be my ears though!

 

[I.D.C.]

My Audio Note Oto is only something like 9W per channel but really doesn't sound like it. In fact it's sounds more powerful than most amps I've used.

Sadly the issue I've had with it is nothing to do with sound quality but more that its been very unreliable. It's put me off valve amps to be honest.

That's a shame. I have run a 10 watt Pathos pure class A for the past 7 years only replacing the valves. This is the longest I have kept an amp so hope it goes on for many years. If not I would defently buy another.

 

[Darth Vader]

Indeed. I also tend to find treble perception drops off too, but they don’t mention that in the article. Could just be my ears though!

That may actually be due to the design of the volume control and associated circuit. The frequency response may change with the volume setting due to capacitance/inductance forming a filter thus attenuating the higher frequencies.

Amplifiers are designed to have normal listening with the volume control at the 12 o'clock position - 10% of full output.

Cheers,

DV

 

[Darth Vader]

My Audio Note Oto is only something like 9W per channel but really doesn't sound like it. In fact it's sounds more powerful than most amps I've used.

Sadly the issue I've had with it is nothing to do with sound quality but more that its been very unreliable. It's put me off valve amps to be honest.

Thats most likely to be due to poor design/build.

Years ago when I had my band all our amps (50, 75 and 100W) were valved. They took a lot of punishment both on stage with high power outputs for several hours and being carted about in the back of a van and up and down stairs. They never let us down.

Cheers,

DV

 

[Arkless Electronics]

That may actually be due to the design of the volume control and associated circuit. The frequency response may change with the volume setting due to capacitance/inductance forming a filter thus attenuating the higher frequencies.

Amplifiers are designed to have normal listening with the volume control at the 12 o'clock position - 10% of full output.

Cheers,

DV

No and no.

Any amplifier doing the first thing would have to be spectacularly badly designed and if talking a passive then worst case is at half max vol electrically. With a normal log pot this will not be at "number 5 on a scale of 10".

So long as a reasonable range of vol setting is available there is no specific vol control setting that amps are designed to be used at.

 

[Chris81]

Indeed. I also tend to find treble perception drops off too...

That is normal, you also don't hear HF linear.

https://en.wikipedia.org/wiki/Equal-loudness_contour

 

[Tony L]

Amplifiers are designed to have normal listening with the volume control at the 12 o'clock position - 10% of full output.

What?! With which source? Bit of an output difference between say a Quad FM3 and a 30ips studio recorder!

 

[Woodface]

If my volume pot was ever at 12 o’clock I think the neighbourhoood would get rather cross. Normally it barely gets past 9.

 

[Tony L]

It’s actually a problem at times here as so much of my kit is vintage and predates the 1.5V (almost) standard for preamp/power amp matching. Thankfully my Verdier valve preamp has internal presets for different output levels so is usable with the 303 even with very efficient speakers. The Leak is only usable with a passive preamp as it is so high gain, though I have a good one so that’s no issue.

 

[matt j]

If my volume pot was ever at 12 o’clock I think the neighbourhoood would get rather cross. Normally it barely gets past 9.

Mine doesn't get above 7 and that's with the DAC set at -15db...

It goes up to 8 with vinyl, I shudder to think what would happen if I turn it up to 11.

 

[Colin123]

If my volume pot was ever at 12 o’clock I think the neighbourhoood would get rather cross. Normally it barely gets past 9.

Mine doesn't get above 7 and that's with the DAC set at -15db...

It goes up to 8 with vinyl, I shudder to think what would happen if I turn it up to 11.

This is interesting, and what 'time' do they start?

Mine starts around 7 and play at 10+ depending on my mood.