Glenn in an ADS thread, now you know which Glenn, @GD70, made this statement about his amp: This triggered one of my pet peeves because it makes it difficult to compare amps. I asked whether this was a bench number or a specification. He responded that it was a bench number. Here is the response I moved from that ADS 910 crossover discussion to keep that thread clean. Well that is how Techs test stuff and it is one way we used to 'claim' power output. The FTC rule of Nov 1974 stated any 2-channel home amp would need to be preconditioned for 30min to 1 hour (IDK which) at 1/3rd power, the most demanding power output level for the common class A/B amps. Then the power output was taken. This spec must include ALL of the following: Power in Root Mean Square (RMS) watts Impedance of the load Frequency response of the power Maximum THD for this power How many channels were driven Such as this spec for Glenn's amp collected from the service manual data: 150wpc@8Ω, 20-20kHz, 0.003% THD, Both channels driven. (more anon) Because of these requirements, amps got rated more conservatively but the numbers were completely comparable JVC to Crown to Pioneer. Issues with this test were the need for better heat sinking to avoid thermal shutoff from the preconditioning and some amps did shut down during this test. The impedance of the load, some makers used both a 8Ω and 4Ω load and gave both numbers. Some companies didn't. With a big enough power supply many units would double down, without that some would have very similar power at 4 or 8 ohms. The lack of a 4Ω rating is not an indication that the amp can't handle 4Ω loads, one needs to check the back around the speaker connections to see if there were any ohm ratings for the speakers. Then you have the frequency response of the power. If you look at the bottom units early on, these were frequently rated at 40Hz to 20,000Hz, 20Hz requiring a lot more energy from the power supply. The choice of how many channels were driven, well if only one channel is driven the power supply can supply just that one and there is more for the one channel to get a higher number. Today's techs mostly use a single frequency and and a single channel. After the unit warms up they drive the amp to clipping and get a number. This is an indication of max power output at the frequency selected somewhere in the middle of the band, like 1,000Hz, where an amp has more oomph. Here is my issue with this overall. Without saying whether the watts number is the benched or rated number, the number posted can not be used to determine what power your amp has for comparison purposes. Just saying 210 is to me a meaningless number. Glenn has an amp rated at 150 wpc that was tested recently on the bench to produce 210 watts, a way that both numbers can be compared to other gear if the bench number is available. You can look at classicaudio's site for gear for sale where they bench the units and you can see that all amps far exceed their rated power level. Example Marantz 2270, 70wpc rated, 90 watt tested. Common on smaller units is 10% over. On bigger units that increases to 20% over, 20-30 or more watts higher than specification. Now for the good part, Glenn's amp at 60 over or 40% is very healthy based on info I have found for all sorts of different amps over the years...on the web. More on the issue of being able to compare numbers, the numbers, if not explained, don't mean crap because of the 10-40% difference between the specification and the bench power in RMS. Guys want the big number and go with that without stating the method of test for that number. This makes it difficult to compare an older benched unit to a more recent amplifier that has not been benched. I have an early 90s amp, 150wpc rated that was upped to 185 specification during its life, that also specified 300, then 330 into 4Ω. I can't really compare that to a 210 watt amp unless I know that was the bench number for this 210 watt amp. The early 90s amp has an output current of 50 amps per channel, something that was not mentioned in older amps. There are some speakers that do demand high current. Things keep changing. As to the specs for the JVC M-7050 amp, the THD is 0.0004% at 150 watts at 1kHz, 0.003% max between 20 and 20kHz and 0.03% max for 20 to 100kHz. With a 300µV/sec rise time, 120dB S/N. 0.003% IM distortion and a wide bandwidth it should be one heck of an amp. It is on my radar. Back to this thread then, how do you talk about the power your amp has?