Is 50 watts (@ 8 ohms) per channel enough?

[bretty]

Hey guys and gals,

Looking at getting an amp. It is 50 watts per channel and the speakers that they will be running are Tannoy Eyris 3 way floorstanders, that the official spec says can run between 20-150rms. Is 50watts enough to get the most from the speakers?

Thanks all 

 

[drummerman]

I'd say it's the minimum sensible power for purely solid state. Any less and dynamic compression or a lack of grip/control will most certainly be obvious at times.

Some companies make over-engineered power supplies to compensate for all-out power (Naim) but even there it's plain obvious that something has to give when driving demanding speakers or at high volume.

Many other factors, most of all the speakers used, make more impact on sound quality but if I had to choose between two good amplifiers, one low powered the other with a few more watts, it's the latter I'd choose, regardless of speaker sensitivity.

regards

 

[plastic penguin]

'Yes' and 'No' - if a speaker has a high sensitivity i.e. 90db + and you have a small - medium sized room then 40/50 watts will suffice. My A65 sounds wonderful (for the money) powering my RS6's

 

[drummerman]

plastic penguin:'Yes' and 'No' - if a speaker has a high sensitivity i.e. 90db + and you have a small - medium sized room then 40/50 watts will suffice. My A65 sounds wonderful (for the money) powering my RS6's

Yes but they will sound better with an A38, money not being an issue and probably better with any of Arcam's more powerful amplifiers. Higher sensitivity doesn't mean the speaker doesn't benefit from control/grip and power but like I said, there are other factors to consider.

regards

 

[plastic penguin]

Absolutely, DM - my point is if you compact floorstanders in a medium to small room the sound should fill the room and achieve enough grip to satisfy.

 

[Anonymous]

I've always felt that even 100watts is not enough at times - sometimes my Arcam A32 will begin to loose control of the bass and stress the treble when playing a CD at -20db. That said, my JVC has less power (70watts quoted) but will go much louder without distorting and I've never got it to the point where it's being stressed.

I think for truely reproducing an orchestra on 90db speakers, at least 200watts is required into 8ohms.

 

[Anonymous]

Lots of watts are needed to avoid clipping, for good clean power, the ability to grip the speakers, and to go loud without the sonic character changing.

Watts are expensive. You need pricey power supplies, heatsinks, output devices, etc.

Try a good amp with a few hundred watts and you'll be amazed at how much better your speakers become (unless they are super sensitive and don't require it).

 

[Tony_R]

bretty:
Is 50watts enough to get the most from the speakers?

As an electronics engineer with 25+ years experience my advice to you would be this:

If your listening room is an average size ( 12 x 15 ft ) then I would say that for practically any music, listening at neighbour friendly levels (assuming a semi) 50w is more than adequate.

Back in the late 70's I did a disco in a small hall with my JVC JAS22 amp ( 40w per channel RMS ) with a largish pair of speakers. This amp had power meters on the front and the *average* (not peak) power output was about 25w rms. Comfortably within the reach of this amp.

You'll be surprised at just how loud 1w per channel is with an average speaker (standmount of floorstanding). Just ask any owner of a valve amp...

There has been mention of "grip on speakers" and so on - this is not a function of power output, but damping factor.

"Damping factor" is the amplifiers ability to 'control' the speaker - e.g. when the woofer cone should be stopping after a bass note etc.

Happy listening,

Tony.

 

[chebby]

Tony_R:As an electronics engineer with 25+ years experience my advice to you would be this:If your listening room is an average size ( 12 x 15 ft ) then I would say that for practically any music, listening at neighbour friendly levels (assuming a semi) 50w is more than adequate.

I would concur. My speakers are about 90db efficiency (6 ohms) and I have a 25watts per channel amp in my Solo-Mini. I never need the volume beyond 45 (fairly moderate) to get an impressive sound from my Rega R3's.

However, like megapixels in cameras and 0-60mph times in cars, there is nothing to be gained from telling your mates your hifi is 25 watts per channel.

There are some seriously loud speakers out there that only need 10 - 15 watts to do physical damage to nearby crockery and some speakers that need 100 watts to be heard in an adjacent room (with the adjoining door open)!

If told that someone has an amp capable of 400 watts per channel, in their living room, I sort of wonder why unless their living room is the great hall in Castle Howard. (Or they have a mailbox full of lawsuits from angry neighbours and permanent tinnitus.)

I am having great problems trying to find a quality power amp with around 40 - 50 watts per channel to partner with a future Benchmark DAC1 Pre. Mostly they are 80 - 100 watts perchannel (or more) at the price range I am looking at. (Where is the equivalent to the old Arcam P75? That would be just right.)

I may need to look into valves (class A) but I don't want to grow a beard and I dont own any sandals!

 

[Tony_R]

You only need to go into Currys / Comet / Dixons (or whatever it's called these days) and listen to the amount of noise one of those ghetto blaster "Hi-Fi" / boom boxes can make..... In what is a very large area too...

And most of those are around 20 - 25w RMS per channel... And mostly failry small speakers too.

Tony.

 

[Anonymous]

I am confused by this, having read a lot of hi fi magazines they generally concur that speakers will sound better with a more powerful amp and indeed there is a world of difference between my Rotel RA931 MK11 NAD C320 followed by my newest amplifier NAD C352 of course you could point to the electronics to but surely the power of the amp has to be a factor?

In fact my general experience is that a lower powered amp struggles and strains when the volume is turned up

 

[chebby]

Depends on how loud you need your music and how efficient the speakers are.

Are you a headbanger like "200 watts minimum" Hughes or someone who just likes to listen to a high quality sound at moderate volume levels?

None of us really knows what each other considers loud. At concerts you may be the guy with his head glued to the bass-bins who SHOUTS for 3 hours afterwards (and will be partially deaf by the time he is 35) and needs his hifi to be exactly as loud at home. Pointless taking advice from you (whoever 'you' are) on minimum system power requirements if I enjoy Jazz and Tudor Sacred music late at night in a quiet room.

 

[Anonymous]

Tony_R:
Back in the late 70's I did a disco in a small hall with my JVC JAS22 amp ( 40w per channel RMS ) with a largish pair of speakers. This amp had power meters on the front and the *average* (not peak) power output was about 25w rms. Comfortably within the reach of this amp.

Absolutly wonderful amp with an awful volume control! Fancy JVC wrecking it with a vertical slider!

 

[the record spot]

My current amp is 65w per channel, I'm not too fussy about ear splitting volume, been there, done that in my youth, but something like the NAD C372 with it's 150w per channel sounds interesting based on the control for the speaker mentioned above. Also, don't the MF Superchargers get a good review for a similar reason? Been a while since I read the review mind, so I might be out on some of the finer points of the details there.

 

[Tony_R]

Hughes123:Tony_R:
Back in the late 70's I did a disco in a small hall with my JVC JAS22 amp ( 40w per channel RMS ) with a largish pair of speakers. This amp had power meters on the front and the *average* (not peak) power output was about 25w rms. Comfortably within the reach of this amp.

Absolutly wonderful amp with an awful volume control! Fancy JVC wrecking it with a vertical slider!

No sliders on this one Hughes, this had a conventional rotary control.

P.S. Hughes, if you ever want to sell that A-X5 of yours.... <please!>

Tony.

 

[Tony_R]

the record spot:My current amp is 65w per channel, I'm not too fussy about ear splitting volume, been there, done that in my youth, but something like the NAD C372 with it's 150w per channel sounds interesting based on the control for the speaker mentioned above. Also, don't the MF Superchargers get a good review for a similar reason? Been a while since I read the review mind, so I might be out on some of the finer points of the details there.

Massive amounts of power does not a good amp make...

There were (and are still) many amps out there with 40w or less per channel that demonstrate excellent control of a speaker.

Damping factor helps, but soe does current delivery.

One of the major failings of early Jap amps was that they could deliver (for arguments sake) 100w when one channel was driven, but try driving both channels and that would drop to about 80w per channel - this being because the power supply could not deliver enough current.

In my experience, amplifiers with hefty power supplies tend to deliver good bass (although this is not always the case) but this is down to good control of the speaker. But this also depends on the design of the output stage etc, etc.

Tony.

 

[Anonymous]

Tony_R:Hughes123:Tony_R:
Back in the late 70's I did a disco in a small hall with my JVC JAS22 amp ( 40w per channel RMS ) with a largish pair of speakers. This amp had power meters on the front and the *average* (not peak) power output was about 25w rms. Comfortably within the reach of this amp.

Absolutly wonderful amp with an awful volume control! Fancy JVC wrecking it with a vertical slider!

No sliders on this one Hughes, this had a conventional rotary control.

P.S. Hughes, if you ever want to sell that A-X5 of yours.... <please!>

Tony.

Wow! That's nice! I could have sworn that had the SEA controls and the slider volume control, but it must have been the 44 model...how much would you pay for the A-X5?

 

[bretty]

thanks for the comments.

Ok, I get the 'damping' thing, but I don't know how it's measured. I've had a look at the specs. Is 'THD' the damping?

If so, it's rating is: THD@impedance: 0.07% @ 8 ohms.ÿ

Could one of you knowledgable folk tell me if this is a good rating?

Many thanksÿ

 

[Anonymous]

THD stands for Total Harmonic Distortion - it's basically the amount of distortion an amplifier produces at its output stages and is normally quoted at near full power of the amplifier into a common load (ie. impedence) such as 8ohms. It is also normally quoted at 1khz or from 20hz-20khz. This is not a true measure of the distortion of an amplifier however, especially because of the 3rd and 4th order harmonics which play a big part in the "richness" of the amplifier.

 

[Tony_R]

bretty:
thanks for the comments.

Ok, I get the 'damping' thing, but I don't know how it's measured. I've had a look at the specs. Is 'THD' the damping?

If so, it's rating is: THD@impedance: 0.07% @ 8 ohms.

Could one of you knowledgable folk tell me if this is a good rating?

Many thanks

No - THD is "total harmonic distortion".

There should be a rating called "damping factor" which is just a number - it has no 'label' as such...

And THD should usually be given at various power outputs. 0.07% is a fairly typical figure, the best amps can achieve 0.0001% in some case - again this will be measured at different frequencies and power outputs.

Typically at the very least, the distortion will be rated at 1khz ( 1000 hertz ) into 8 ohms.

Which model of amplifier are we talking about? Anything specific?

Tony.

 

[Tony_R]

Hughes123:

Wow! That's nice! I could have sworn that had the SEA controls and the slider volume control, but it must have been the 44 model...how much would you pay for the A-X5?

Hughes, you are indeed correct about the JA-S44 - that did have a slider.

As for the A-X5 - this is not the place to conduct our business - would you be kind enough to email on this email address?

Sorry it's an image - to avoid the spammers!

Thanks,

Tony.

 

[bretty]

It's Harmon kardon AVR 255.ÿ

I couldn't see damping factor, i'll have another look.ÿ

 

[Tony_R]

Just been checking the specs myself, and no damping factor mentioned.

However, a High current power supply and independent supplies front and rear are mentioned.

Plus, the power drop with all 7 channels driven is not bad - which does seem to confirm their claims of a high current (or to use the lingo - 'stiff') power supply. This thread has gotten so long now - I can't even remember why you were asking the question in the first place! But if the title is anything to go by - assuming you have a reasonable sized room, and not horribly inefficient speakers - this is more than adequate...

I also note they quote the power specs to the FTC standard.

"The FTC standard, established by the Federal Trade Commission, requires a manufacturer's stated power rating must be met, with both channels driven, over the advertised frequency range - usually 20 Hz to 20 kHz - at no more than the rated total harmonic distortion (or THD)

The FTC rating gives you the average power output for both channels over a wide frequency range and lower distortion level. This is a much more conservative - and realistic - measure of an amplifier's average output power."

Quoted from this site: http://www.soundandsong.com/Issue004/004_PowerAmpRatings.html

 

[Anonymous]

Off-topic: Just sent you an email, Tony.

 

[bretty]

many thanks for taking the time, Tony.