mhardy6647
Lunatic Member
nice "out of the box" solution -- but you have to know the heat capacity of the oil. Water has (I think!!) a higher heat capacity than oil, and I do know what it is: 1 calorie per degree C per g (1 kcal/deg C/kg).
How To Measure Watts Per Channel
- Thread starter jblmar
- Start date
Lefty
Super Member
mhardy6647 said:
I believe it was using water in the artical I read years ago, but I was reluctant to say as unless steps are taken to insure low conductivity there could be problems
Oil is fundementaly a good insulator as long as contaiments or conductive additives are not introduced. Ham radio operators have used oil filled 50 ohm power resistors as dummy loads forever but I belive few have used the rise in temp in power calcs, but rather just used ohms law.
Lefty
mhardy6647
Lunatic Member
high resistivity water (18 megOhm-cm) is easy to come by in my line of work! 
Fred Longworth
audio fanatic
Back in the seventies and early eighties, the FTC actually regulated power output. If an amp said 100 watts per channel in the specs, it really had to deliver that. Inside, you would see hefty output transistors and big, black heatsinks.
Somewhere in the Reagan era, the FTC began to back off. This lack of regulation has increased over the years. Today, I regularly see home-theater amplifiers rated at 100 watts per channel with ten or twelve plastic output transistors mounted on a single, small, finless, bright-aluminum heatsink. No way on God's earth it can meet the official specs. Alas, the regulators turn the other way. Even disingenuous sales are good for the economy.
Fred Longworth
Somewhere in the Reagan era, the FTC began to back off. This lack of regulation has increased over the years. Today, I regularly see home-theater amplifiers rated at 100 watts per channel with ten or twelve plastic output transistors mounted on a single, small, finless, bright-aluminum heatsink. No way on God's earth it can meet the official specs. Alas, the regulators turn the other way. Even disingenuous sales are good for the economy.
Fred Longworth
outlawmws
On the Run
Fred Longworth said:
My understanding is that once they got away from "Stereo" and into multi channel HT, they no longer met the "Definition" of Stereo, and the 70's regulations no longer applied. And of course, no one in the current "Business is #1" economy we have now will say anything about it... :thumbsdn:
mhardy6647
Lunatic Member
AFAIK the FTC regulations (possibly altered since 1975) still apply to 2-channel home audio amplifiers and receivers. That's a pretty small piece of the current 'home entertainment electronics' market today though... and the FTC rule never applied to car hi-fi (can you tell?).
Chris Brown
Super Member
Fred Longworth said:
Most of the equipment I’ve come across seems to be rated reasonably accurately, they just don’t tell the whole story. “100 watts per channel” just usually now means at 6ohms, one channel powered, at 1khz, rather than all channels powered, at 8ohms, 20hz-20khz.
Lefty
Super Member
Chris Brown said:
And that's the point. While each amplifier channel might be capable of 100 watts the system power supply cannot support all channels at that level. Hell I wonder if it could supply 2 channels at 100 watts :scratch2: The FTC rules were a blessing for consumer at the expense to the manufacture's marketing practices that cause their implementations. Today, who is watching out for the consumers interest :scratch2:
Lefty
