I cant seem to find the actual specification of the amplifier, can you pint to this or add it to the product write up please.
All I see is 79w per speaker, no ohms etc etc etc.
You know, I thought we had one somewhere too and now I can’t find it either, guess we’ll have to remedy that! Anyway, the amplifiers we use are TDA7492E and in the stereo BTL mode we’re using them in are capable of (per speaker):
| 4-Ohm | 6-Ohm | 8-Ohm |
--------+-------+-------+-------+
1% THD | 61 W | 44 W | 34 W |
10% THD | 79 W | 57 W | 44 W |
See the TDA7492E datasheet for more.
This is just the specification for the amplifier chip. What about the system overall? Total power on all channels, frequency response, THD+N, and so on.
Hi Concorde,
Welcome to the forums and thanks for posting! That is a good question. Yes we do have measurements, we just never took the time to clean them up and get them posted. Thanks for asking, you the first person to inquire on this. Stay tuned, we will get them together and get them out ASAP.
Jason
Thx, looking forward to it. Also, have you considered loaning a unit to Amir at AudioScienceReview?
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Yes, would like to see this.
Yes we do have measurements, we just never took the time to clean them up and get them posted.
@jason, can we see the measurements now?
And how about loaning a unit to Audio Science Review?
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Any updates on actual measurements?
Months later and still no real specs or measurements. Looking a lot like vaporware at this point 
Yeah, no kidding. I want to like this product, but the lack of communication about basic specs is concerning.
Has anyone from the community taken proper measurements on this thing?
Hey guys, I apologize for the extreme delay in getting back on this. We were hoping to get to some better testing done sooner but we’re a small company and I’ve been pulled away to fight some other fires recently. On the plus side our software team has still been plugging along on some awesome updates!
Jason is partially correct, we did a lot of qualitative testing and some minor quantitative testing to get AmpliPi where it is today. Our first prototypes had a lot of noise so we just focused on tests to minimize that. AmpliPi now has a S/N ratio >95 dB.
As far as other standard audio tests like the max power, frequency response, crosstalk, and THD(+N), I’m working on those now. Sending an AmpliPi to Audio Science Review sounds like a great idea too, we certainly would welcome independent input our how good we’re doing. At this exact moment we unfortunately don’t have any spare AmpliPi units. Hopefully we will soon, production is working on ramping up our rate of production.
Building up our test rig is a work in progress, but I’m reasonably confident in our first measurement: a single stereo channel with 32 W each into 8-ohms resulted in a THD of 0.054%, crosstalk of -75 dB. Any more power than that and the output clips. I will test with all 6 stereo outputs, and repeat everything with 4-ohm loads.
I will note that we already know we can’t do max RMS power on all 6 stereo outputs. The power supply in AmpliPi is capable of putting out 350W. Everything other than the amps require ~20W to run, and the amps are ~90% efficient (to be measured better). So the theoretical max output power per zone with all zones on is roughly 24 W. That may or may not sound like a dealbreaker to you but we’ve been powering 18 zones at MicroNova with that (1 main unit and 2 expanders) and we’ve never hit the power limit during normal listening sessions.