Originally Posted by Sean Parque
Hi Gabriel. Just a quick note here. The amp does meet it's published specs. We measured the amp and that is how the spec was derived. We did not make something up and then hope it could do it ;) Gene measured the amp differently than us and with different parameters so he gets a different number. Nothing wrong with that. Also nothing wrong if you don't buy the MPS-1 based on this. I just wanted to note that it does indeed meet it's spec and our test is even published in the article.
Also, not that this matters one bit if you are looking purely at specs but they were hitting 120dB according to the article. How loud do you listen? :D
Thanks but I'll trust an independent review long before I trust manufacturer's specs. High end amps also tend to have damping factors well above 200 whilst the Emo seems to be a bit above 50.
Especially when you came up with your specs by:
According to Emotiva, this measurement was taken at 4 ohms (1% purely resistive load) and with a line voltage of 120V ac (1KHz input frequency). In this graph you can see they achieved 300W at 1% THD. Though my contention here was they were using an automated script in Audio Precision to find maximum power of the amplifier whereas my tests were using continuous tones. What likely occurred here is their measurement captured the power of the amplifier before the clamping circuit kicked in and limited the power output. This is a common measurement some publications use which I don't really like for that very reason. I like seeing steady state full bandwidth power response to see what the amp is really doing.
I was able to achieve a maximum unclipped power of 175wpc into 8 ohms with Vin=1.65V Vout=37.39V unbalanced and about 255wpc into a 4 ohm load with Vin = 1.42V and Vout = 32V. Once I exceeded these measurements, the clamping circuit kicked in rounding off the signal and dramatically increasing distortion. Based on this, I would rate this amp to be a 175wpc into 8 ohms and 270wpc into 4 ohm, not 200wpc / 300wpc 8/4 ohm respectively like Emotiva rated in their literature
When I informed Emotiva on my findings, they suggested that my test conditions were preventing me from achieving their published ratings due to line voltage sag. I respectively disagree since I was only testing one channel and monitored my line voltage to be a constant 124Vrms throughout the entire test. In addition, this was the first amp I tested that did not meet its power specification
. However, please note this is also the first amplifier I tested with a thoughtful limiter circuit which does make it a bit tricky to accurately test.