Review and Measurements of Amazon Link Amp

[Jazz]

I got one on sale late 2021 holidays. I have to say, it is going back. Just too harsh. Even running my normally quite warm and smooth AKM DAC to analog. Harsh. The internal Cirrus Logic DAC is warmer but also duller. If it was all I had or heard in DACs, it would be great! But, amps and DACs can be warm and lively but not be harsh. This was just harsh. I tested an Echo Link a few years ago on a Yamaha amp and it sounded similar with the internal DAC — good, even great for 95% of humans — but with the non Amazon amp, playing lossless, it sounded fantastic. But, it was just an Echo with more connections at that point. I ended up returning that too.

 

[EdTice]

There is analog input and output. Former can be used for your analog gear and the latter, for use as a DAC or pre-amp. There are issues with this mode though. See later in measurement section.

Ah, a sigh of relief. Performance actually improves a bit using analog in! Noise floor is flatter and lower although not enough to make the SINAD any different. Putting that value in context of other power amplifiers tested, we get this:

@amirm I'm very curious about this. These amps are so appealing at their price point, that I have two of them with which to experiment and largely based upon the ratings here. But my experience is that the analog input always goes through an analog->digital->analog conversion that just can't be avoided. The only way I can think for this to happen would be that the a->d conversion causes some degradation that happens to offset some distortion introduced in the d->a conversion.

I tried to use this amp to power a set of surrounds from analog input and the results were catastrophic. Was the delay measured? When I attached this amp to the output of the AVR it sounded obscenely bad. I tried fussing with levels to no avail. Took advantage of my family sleeping late this morning and tried to run the AVR room correction. Turns out that the A->D->A conversion is so high latency that the AVR considers the surrounds >80ft and that's more than the DAC in the AVR can handle.

At the price point, I can't really be unhappy with the amps, but with such long delays, one had better use them strictly as music streaming devices. They won't substitute other places where one might use an integrated amplifier. I'm not sure I'd hook up analog sources to this. I'm not surprised by this outcome since the amp does have a setting (when the app works) for what to do with analog input (local only or stream around your house). I was naive and hoped that "local only" would just send the signal to the amp section but that does not appear to be the case.

 

[EdTice]

Power Amplifier Measurements
Important note before we get into this section: during testing the results were a complete mess at lower frequencies. The graphs were literally not readable with very high variations of THD+N. So I spent a few hours with my son working through it and turned out some of these class-D amps cause frequency modulation at low frequencies which throws off the analyzer notch filter. The result was that THD+N would go from correct value to 20%+ which would totally screw things up on the graph. I found a good work-around for this which made the measurements look a lot nicer. Alas, this means you can't quite compare these results to previous measurements where this issue was visible. Fortunately we had very clean amplifiers such as Hypex NC400 without this issue so those results stand.

Is it possible that the results were a complete mess due to the insane delay of the audio signal? I'm going to go back and retest today before I return my two units. But it seems that this device should *not* be considered an integrated amplifier as it can't be used for many of the things one might want to use an integrated amplifier for! It can't power speakers from a prepro or even surround rears hooked up wirelessly because the delay is too long. Wouldn't work for live performances either. Seems there should be a category for streamers whose amps cant be repurposed. And that category would not be properly named "integrated amplifier" since well one can't use it as an integrated amplifier! USB audio interfaces with reasonable delays exist. My guess is that the built-in delay is there intentionally to allow for network buffering. The amp can distribute analog input to other devices via WiFi. The local delay is intentional so that packets can be transmitted and received at other devices.

I have not tried using these amps with a Fire TV stick where the Fire TV stick does the decoding and acts as an AVR. that's supported with these amps. The Fire TV stick would have to buffer the video to match the audio output but that's not a very demanding task these days. But I don't know of any DACs that can introduce this much compensation. The Fire TV stick must be adding the delays pre-DAC which again is interesting. But it still means that the Echo Link Amplifier doesn't meet any current definition of integrated amplifier!

 

[Jefrpol]

Any owner of the Link Amp use it as an endpoint (zone) with JRiver?