Vintage Receiver Power
- Thread starter cool9
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Brian
An Old Geezer
Watts - apples to radishes. We are about where we were for years before the Feds got involved. Back then power ratings depended on how imaginative an engineer could be and today we are back there. In the early '70s or late '60s, the Feds were fed up with advertising that at best could be misleading, though not false. Companies had standards from rms, IHF, music power peak and even peak to peak. Then it also depended on the frequency response, and distortion. Also, depended on the effects of having 2 amps working off the power supply.
The FTC, finally mandated that music system audio amps had to be advertised showing the rms power rating into each impedence advertised using any other power rating systems. The rms measurement required pre-conditioning and across the audio band. You began to see some interesting specs as the advertised rating had to be balanced against the distortion at the rated power. Hence maybe a company could have an added 1 or 2 watts at 1% then at the lower rating at .05% but, advertising 1% distortion would be death. Also, a new term started to come into play, headroom. Not totally define as a standard but more or less the difference between the rms and the point where a signal actually clipped.
Somehow manufacturers are now getting around the FTC requirements by classing equipment other than audio, i.e. HT and Washington no longer has the will to enforce the mandate. So we have come full circle and what you see today for most stuff is as confusing as it was not long before FTC.
Come to think of it, the tube era seemed not to have as many confusing power definitions as the early SS units.
The FTC, finally mandated that music system audio amps had to be advertised showing the rms power rating into each impedence advertised using any other power rating systems. The rms measurement required pre-conditioning and across the audio band. You began to see some interesting specs as the advertised rating had to be balanced against the distortion at the rated power. Hence maybe a company could have an added 1 or 2 watts at 1% then at the lower rating at .05% but, advertising 1% distortion would be death. Also, a new term started to come into play, headroom. Not totally define as a standard but more or less the difference between the rms and the point where a signal actually clipped.
Somehow manufacturers are now getting around the FTC requirements by classing equipment other than audio, i.e. HT and Washington no longer has the will to enforce the mandate. So we have come full circle and what you see today for most stuff is as confusing as it was not long before FTC.
Come to think of it, the tube era seemed not to have as many confusing power definitions as the early SS units.
Maybe not as easy to hide things with tubes? If you're running a certain species of tube in say push/pull pairs you'll get a pretty predictable output and a lot of folks would have an idea what that might be. With those new-fangled transistors it was another matter altogether.
zenith2134
Lunatic Member
I do agree that most listeners only need 40 to 60 wpc RMS, if you care to call them RMS. Some folks claim there is no such thing as an RMS watt.
You get my drift though, 40 to 60 'real' watts.
And yep, speaker efficiency plays a major part here. With my 12wpc tube amp, I only need roughly 1.5wpc to make my family complain. And my speakers ain't no 98dB/1w/1m either! More like 89.
So, to have 120wpc SS I never, ever, crank it up that high...but the headroom adds a certain something to the sound. I like the idea of having high headroom, but if the first watt sucks than the other 119 will.
You get my drift though, 40 to 60 'real' watts.
And yep, speaker efficiency plays a major part here. With my 12wpc tube amp, I only need roughly 1.5wpc to make my family complain. And my speakers ain't no 98dB/1w/1m either! More like 89.
So, to have 120wpc SS I never, ever, crank it up that high...but the headroom adds a certain something to the sound. I like the idea of having high headroom, but if the first watt sucks than the other 119 will.
Fomoco1649
Well-Known Member
Agreed....just purchased an SA 8500 Amp rated @ 60WPC....I wasn't sure what to expect until I got home....Wow....plenty of power...I was told the older equipment was rated in RMS....