Arcam AV40 AV Processor Review

[Krobar]

Interestingly, the AudioControl X9 has a firmware of 1.29 whereas the JBL and Arcam are at 1.28. The JBL/Arcam are 4/28/2020 and the Audiocontrol is 4/29/2020 so it suggests that AudioControl is doing *something* extra.

The firmware on these are in 2 parts. The OS called bit image.swu which does streaming, control and lots of other bits (Like receiving the data from Dirac) and the DSP firmware which does the most of the low level essentials. The image.swu in the Audiocontrol is identical, I suspect the difference in the X7 fw file is to allow for the two extra XLR inputs but there could be other differences.

When I recovered my AV40 over SSH from a bad flash it gave near root access to the OS. The scripts reference the one minor version difference of the Audiocontrols as part of the same update bundle so I suspect they are developed in tandem but Audiocontrol certainly decide when to release firmware for the X series and have so far been more cautious than Arcam and JBL.

 

[Lsc]

Our company is a dealer for Audio Control. I can reach out to them but don't know the people personally. But I really rather someone buys one to test rather than me asking for a loan with expectations that come with it.

Do you have dealer demos that you can test?

 

[amirm]

Do you have dealer demos that you can test?

No, our company only does custom integration for homes and businesses. We don't stock anything. I can buy them at dealer cost of course but they are way too expensive even with that discount just to test it here. If someone is interested in one, I can buy, test and then forward it to them.

 

[Lsc]

No, our company only does custom integration for homes and businesses. We don't stock anything. I can buy them at dealer cost of course but they are way too expensive even with that discount just to test it here. If someone is interested in one, I can buy, test and then forward it to them.

That sounds like a good arrangement! If there is a product you want to test, you can have a sponsor who would be willing to buy the unit at the dealer cost - but instead of getting it new, it would be opened, tested and evaluated. Sounds like a win win. This would only apply to products you guys sell of course but if you have a wide range of products, I can see it being mutually beneficial and excellent for the site.

 

[GXAlan]

When I recovered my AV40 over SSH from a bad flash it gave near root access to the OS. The scripts reference the one minor version difference of the Audiocontrols as part of the same update bundle so I suspect they are developed in tandem but Audiocontrol certainly decide when to release firmware for the X series and have so far been more cautious than Arcam and JBL.

With near root access, how Amazing would it be if you could add functionality to the firmware...

 

[Luminous White]

I might still be getting that AudioControl as I’m in the industry and have access to very good pricing. However that being said I just found out what I could get a Trinnov for and am a little star struck and wide eyed. I might skip
the AudioControl even though I’m dying to see it measured because well...Trinnov. For me It’s the king, and though I don’t have a measurement of that either, subjectively at least it blew me away, and I like that it’s a long life product with actually very fair upgrade costs. However I can vouch (again subjectively, take with a grain of salt) that AudioControl’s class H amps are brilliant especially in balanced dual mono mode, and I’m struggling to decide between those or a hypex/purifi setup. (Benchmark is class H, I know this doesn’t mean they compare though lol, but an interesting coincidence as class H is rare) Amir what would you do?

 

[TimoJ]

You may be asking if the performance improves at other output levels so let's see if that is the case:
View attachment 62934

As is typical of these AV products, where you set the volume determines different gain stages that get turned on and off, impacting performance. Using the same volume position as previous tests, we see that best performance is at 3.1 volts than 4 volts. Improvement is negligible though to the tune of just 1 dB.

Have you somewhere explained how this measurement is done? Is input level adjusted and the curves represent that? The signal source was AP software and output via PC HDMI?

 

[amirm]

Have you somewhere explained how this measurement is done? Is input level adjusted and the curves represent that? The signal source was AP software and output via PC HDMI?

It is a simple test and yes, that is what it does. Digital samples are played and analog performance is measured from the processor.

 

[ririt]

Thanks Amirn to clarify the situation. I am looking forward seeing your additional measurements...

 

[TimoJ]

Their testing involve using a portable class 2 HDMI signal generator. Since they don't see the noise issue there, they automatically jumped to the conclusion that there must be ground loops in my testing. I have explained to them that they need to use a standard consumer video source, not a an HDMI signal generator that is likely to produce much cleaner signal. And that there is no evidence of ground loops per above explanation. I have heard no answer from them.

Have you seen their measurements? Are they much better and close to their published specs? If they are, something has gone wrong in the circuit/shielding design of the AV40. btw. Have you tested if all HDMI inputs perform in a similar way?

 

[amirm]

Are they much better and close to their published specs?

What specs? This is all they show:

SNR relative to 100 watts? What is that? There is no amplifier here to have a reference to 100 watts.

THD+N at what frequency?

They brag about low jitter but there is no jitter spec!

Pre-amplifier outputs are with what source? Analog or digital? HDMI or Coax/Toslink?

Where did they get nominal 1 volt output? On XLR balanced, that doesn't amount to much.

But yes, I have seen some measurements from them. For now, I prefer to not disclose more about what they have said.

 

[Krobar]

With near root access, how Amazing would it be if you could add functionality to the firmware...

It crossed my mind I had access to read and write to I2 busses so could maybe have fixed the DAC filter for example. The web page and how it passes through the rest of the unit made some sense too. I hadn't realised at the time that the level of access was different in recovery mode than in the firmwares prior to 1.24 which had SSH access available in normal operation.

 

[MZKM]

THD+N at what frequency?

It shows in the image, 20Hz-20kHz.

 

[QMuse]

It shows in the image, 20Hz-20kHz.

Yep, that's how I read that as well: "not more than -100dB in the 20Hz-20kHz range". But I'm not really sure if they meant it like that.

 

[amirm]

It shows in the image, 20Hz-20kHz.

That is the way I took it as well and pointed out in my response to them of device "meeting spec" how that is not true. Such a test would need to have very wide bandwidth to include harmonics of 20 kHz and when doing so as i did in the review, we clearly see problems:

We have at least two components that reach -68 dB so likely SINAD would be in 60s. No way it would be -100 dB as the spec indicates.

After I responded to them, I thought maybe they meant that it was 1 kHz measured from 20 to 20 kHz. In which case as I indicated, it need so the test frequency which it does not.

So it is either a useless or incorrect spec in this regard.

 

[Dimifoot]

That is the way I took it as well and pointed out in my response to them of device "meeting spec" how that is not true. Such a test would need to have very wide bandwidth to include harmonics of 20 kHz and when doing so as i did in the review, we clearly see problems:

We have at least two components that reach -68 dB so likely SINAD would be in 60s. No way it would be -100 dB as the spec indicates.

After I responded to them, I thought maybe they meant that it was 1 kHz measured from 20 to 20 kHz. In which case as I indicated, it need so the test frequency which it does not.

So it is either a useless or incorrect spec in this regard.

I am not sure if I understand it well, but the -68db is close to 40000Hz and 60000Hz.
Are these taken into account since it’s out of the 20-20000Hz range?

 

[Dimifoot]

Is it a matter of interpretation of measurements?

 

[amirm]

I am not sure if I understand it well, but the -68db is close to 40000Hz and 60000Hz.
Are these taken into account since it’s out of the 20-20000Hz range?

They have to be if you want to measure the harmonic distortions of a 20 kHz signal. Its second harmonic is 40 kHz, the third, 60 kHz and so on. If you exclude everything above 20 kHz, you are not measuring *any* harmonic distortion! Or noise for that matter. This is my my THD+N versus frequency uses 90 kHz bandwidth. It allows the first few and most powerful distortion products to be included.

 

[Dimifoot]

They have to be if you want to measure the harmonic distortions of a 20 kHz signal.

That’s why I wonder if its a matter of interpretation.

Do you want to measure the harmonic distortion of 20000Hz, or the harmonic distortion in the 20-20000Hz range.

Is there an industry standard?

 

[amirm]

Is it a matter of interpretation of measurements?

No although you can always change measurement setup and parameters to get at a different answer. But yes, there are issues in interpretation. For example, Arcam showed me a jitter graph with their analyzer saying there is no jitter. Yet jitter was plainly visible in their graph! I showed a much more clear version using my analyzer which agreed with their own tests.

In other cases they like to use a-weighting filtering which reduces noise a lot. This is a common technique for manufacturers to get better numbers and hide design/noise issues. All my measurements are unfiltered so that we can see what is going on in real performance of the system.

In some other instances they make up their own targets and then they say the meet it. They say for example that their target for output voltage was their own amplifiers so just 0.9 volt output was the spec. I hold the products to the stereo DAC standards that produce at least 4 volts of undistorted output from balanced out.

Anyway, instead of answering piecemeal, I might summarize their response and provide my explanations.