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Monster Receivers: How much WPC output into 4 ohms? An AK Collaborative Project

Don't forget that the FTC mandated preconditioning (IIRC, 30 minutes at 1/3 rated power) prior to power output measurement. Quite a few components when tested by the hi-fi mags would overheat and shut down during preconditioning, and I suspect many more wouldn't have survived testing to the FTC spec at 4 ohms.
 
mhardy6647 said:
Don't forget that the FTC mandated preconditioning (IIRC, 30 minutes at 1/3 rated power) prior to power output measurement. Quite a few components when tested by the hi-fi mags would overheat and shut down during preconditioning, and I suspect many more wouldn't have survived testing to the FTC spec at 4 ohms.
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Very interesting - does anyone have the FTC testing rules?

So, when a manufacturer decided not to publish 4-ohm numbers for a particular component, this could be due to a number of reasons, including a straight out omission, but also that the particular component failed the test for whatever reason, if I understand the implications of what you are saying correctly.
 
Volts to Watts

Here is a list of how many volts equals how many watts per channel for 8 ohms and 4 ohms. I pulled this data from Oaktree a couple years ago as they did their testing on units that they had refurbished.

From what I can see, if you know how many watts per channel output you have at 8 ohms, you can prety much figure how many watts per channel you would be putting into a 4 ohm load.

The list doesn't go to the highest of the highs for output, but the curves should help figure out where you would be if you have really high output.

//Smorgy
 

Attachments

The Sansui G-33000 lists 330 watts watts at 1kHz for 8 ohms and 450 watts at 1kHz for 4 ohms.
The Sansui G-22000 lists 240 watts watts at 1kHz for 8 ohms and 300 watts at 1kHz for 4 ohms.
Not 20-20,000Hz but it's a rating none the less which is why I gave the 8 ohm rating as well. This is from the brochure specific to these models, there's a copy on hifiengine so I won't bother scanning it. ;)
 
Kernel86 said:
The Sansui G-33000 lists 330 watts watts at 1kHz for 8 ohms and 450 watts at 1kHz for 4 ohms.
The Sansui G-22000 lists 240 watts watts at 1kHz for 8 ohms and 300 watts at 1kHz for 4 ohms.
Not 20-20,000Hz but it's a rating none the less
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It is interesting that Sansui chose to disclose the 4-ohm specs in the brochure for the two big Gs, but omitted them in both owner's manuals.

Thanks for the data! :thmbsp:
 
It is interesting that Sansui chose to disclose the 4-ohm specs in the brochure for the two big Gs, but omitted them in both owner's manuals.
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Marketing 101: In the former case, they were trying to sell potential customers on the models. In the latter, there was no need for the "selling point".
 
Njord Noatun said:
Very interesting - does anyone have the FTC testing rules?

So, when a manufacturer decided not to publish 4-ohm numbers for a particular component, this could be due to a number of reasons, including a straight out omission, but also that the particular component failed the test for whatever reason, if I understand the implications of what you are saying correctly.
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It's the change in rules that's interesting, just like SAE and NET horsepower ratings in the 70's, the 70's amp section was rated continuous at a certain % of distortion at set feq. response, then the rules changed (maybe by manufactures) so it could be a bigger # for peak watts at same specs.
Back then folks knew continuious meant serious:yes:

Craig
 
Technics SA 5760 from service manual

165wpc @ 8ohms 205wpc @ 4ohms from 20-20,000hz .08%thd

175wpc @ 8ohms 230wpc @ 4ohms at 1khz .08%thd

Can anyone verify the same specs for SA5770?
 
then the rules changed
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There have been some changes to the FTC regulation, but the simple fact is that the FTC spec never applied to car audio nor to portable audio nor multi-channel audio. It only applied to home stereo amplifiers and receivers, and, AFAIK, that's still the case.
 
mhardy6647 said:
There have been some changes to the FTC regulation, but the simple fact is that the FTC spec never applied to car audio nor to portable audio nor multi-channel audio. It only applied to home stereo amplifiers and receivers, and, AFAIK, that's still the case.
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Guitar amps too I think.
 
I have a stereo test of 1977. Here are the measurements of the RX-1603
2X228 watt rms into 8 ohm.
250 watt rms 1channel driven into 8 ohm.
240 watt rms 1channel driven into 4 ohm.
273 watt dynamic power into 8ohm 1 channel.
313 watt dynamic power into 4ohm Left channel.
380 watt dynamic power into 4ohm Right channel.
frequenty respons from 2hz to 57 khz @ half power

And now the stereo test from the pioneer SX-1250
2X190 watt rms into 8ohm 1khz.
2X264 watt rms into 4ohm 1khz.
frequenty respons from 9,5hz to 39 khz @ -1db

It gives you an idea :)
 
I've taken heat for this before, too. What's the fascination with hi output? Does anyone around here listen for a long period of time at or near the max rated output of their gear? Some hearing needs to be tested around here, too!

EchoWars said:
Hate to bust ya'all's bubble here, but manufacturer's ratings into 4 ohms are nearly always way off-base. Under-rated, mostly, but quoting their specs is an exercise in futility if you care anything about accuracy.

If that don't bother you, carry on gents.:beerchug:


Edit: You say 'no bench tests'. I generally don't test into 4 ohms, so I have little to offer in that regard, but I'm curious as to why? Also, if you're not interested in bench tests (or tests from magazine lab tests), then I guess accuracy is not an issue...so as far as my first couple 'O sentences in this post...nevermind.:sadwave:
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Tromatic said:
What's the fascination with hi output?
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I am not sure this comment warrants a response as no-one has proclaimed "a fascination with hi (sp?) output" in the thread. The stated and specific purpose of the thread is simply to compile published output numbers under 4 ohms, as opposed to questioning the reason for why the data was published, compiled or even needed.

This thread is not about if a 200 watt amp is better or worse than a 16 watt amp, if that was not perfectly clear from the outset.
 
Smorgy said:
From what I can see, if you know how many watts per channel output you have at 8 ohms, you can prety much figure how many watts per channel you would be putting into a 4 ohm load.

//Smorgy
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No, you can't use the chart that way.

To do so would assume the amp can maintain the same output voltage at 4 ohms as it does at 8 ohms. Very, very few amps can actually do that.
 
Correct. Lower Z loads need more current, and voltage drops.

I know the sx-1050's specs say 120wpc at 8 ohms and 170wpc at 4 if this is of any use. I've yet to own an amplifier which doubles output power into a 4 ohm load. I suppose you need a massively stiff power supply in order to achieve that.
 
whAT about the toshiba sa-7150 ?
rated at 150 wpc @ 8ohms / 230wpc @ 4ohms from 20hz to 20khz .05% thd
and more at 1khz, 250wpc @ 4ohms
 
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