Audio Science Review of Expert 200.

[Antoine]

Not going to comment on this ‘review’ but I think this may be (the source of) the amp: https://www.audiosciencereview.com/forum...ada.12107/

[ogs]

A couple of year old 200 watt amplifier, that can’t produce 20 watts of 20khz into 4 ohms (it shuts down), and no one suspects it might just be faulty? A bad capacitor or some such? Not really a credible result. ASR should try measuring a new one.

If you read the Stereophile review of D-Premier there's similar measurements. Protection hits relatively early on test signals. Music on the other hand works nicely

[Confused]

A couple of year old 200 watt amplifier, that can’t produce 20 watts of 20khz into 4 ohms (it shuts down), and no one suspects it might just be faulty? A bad capacitor or some such? Not really a credible result. ASR should try measuring a new one.

Well, there was the link to the Stereophile review which seems to highlight a similar issue.  Does anyone fully understand this?  From a practical point of view, I have used both Expert and Pro for about seven years now, sometimes at very high volumes, and never once had one shut down on me.  Yet, it appears there is some kind of test that does just that, shuts the amp down.

Can anyone explain this?

I was also a little concerned about the phase shifting thing, until I noticed that this occurs at over 40kHz.

In terms of a bit of Devialet watching, it will be fascinated to see if Devialet drop their normal wall of silence and respond to this.

EDIT: It looks like my post crossed the above from @ogs (we are saying much the same thing) - nevertheless, I would appreciate it if someone can explain this a little.

Second EDIT: @"alaw" - considering Amir's review testing seams to have junked the Devialet - I suspect offers of a new one to test might not be forthcoming. I would not be keen to lend him mine, for example.

[ogs]

Can anyone explain this?

I'm not sure I know, but I suggest the following: The design does not have enough cooling for full power measurements (which uses sustained test signals) so the protection is configured to trig at a very low (safe) level. Music is dynamic in character and thus will not trig protection.
Give a Devialet amp massive (enough) cooling and re-program the protection logic and the amp would also measure at full rate.

[Confused]

Can anyone explain this?

I'm not sure I know, but I suggest the following: The design does not have enough cooling for full power measurements (which uses sustained test signals) so the protection is configured to trig at a very low (safe) level. Music is dynamic in character and thus will not trig protection.
Give a Devialet amp massive (enough) cooling and re-program the protection logic and the amp would also measure at full rate.

This makes sense, however, I recall one time I was running a 18kHz test tone armed a sound meter.  It was quite good fun to turn the volume up and down, and see the SPL meter rise and fall, whereas I could not hear a thing.  (My own heating tops out at about 16kHz)

So I have done the above, and nothing shut down.  Maybe this was only using a few watts?  I might get the multi-meter out at the weekend and test this.

[ogs]

  Maybe this was only using a few watts?

Your Blades are quite sensitive at 91dB (2.83V/1m). 90dB SPL at your listening position would be around 2 watts...

[whatmore]

Amir has reached out to Devialet for a response.
There are questions that could easily be cleared up but I wonder if they will be as woefully uncommunicative on this as they are with pretty much everything else….

[sam1000]

Amir has reached out to Devialet for a response.
There are questions that could easily be cleared up but I wonder if they will be as woefully uncommunicative on this as they are with pretty much everything else….

Since the device is not under warranty, does Devialet really need to respond? How many other manufacturers would respond to similar requests?

Someone on ASC posted the following links for 170 measurement. It's the same hardware. Registration is required to read these report.
This seems to be pretty comprehensive tests, but done only at 1khz.
http://www.milleraudioresearch.com/downl...t_170.html
http://www.milleraudioresearch.com/downl..._lpcm.html
http://www.milleraudioresearch.com/downl...0_usb.html

On the other hand, its about time for Devialet to explain if their units are tested for full power using multiple sign waves. Many people do refer to Stereophile's measurement of original D-premier. I thought that would have been taken care of in last 8 years.

[Confused]

Amir has reached out to Devialet for a response.
There are questions that could easily be cleared up but I wonder if they will be as woefully uncommunicative on this as they are with pretty much everything else….

Since the device is not under warranty, does Devialet really need to respond? How many other manufacturers would respond to similar requests?

Someone on ASC posted the following links for 170 measurement. It's the same hardware. Registration is required to read these report.
This seems to be pretty comprehensive tests, but done only at 1khz.
http://www.milleraudioresearch.com/downl...t_170.html
http://www.milleraudioresearch.com/downl..._lpcm.html
http://www.milleraudioresearch.com/downl...0_usb.html

On the other hand, its about time for Devialet to explain if their units are tested for full power using multiple sign waves. Many people do refer to Stereophile's measurement of original D-premier. I thought that would have been taken care of in last 8 years.

I note that Hifi News' Paul Miller also tested the Original D'Altelier.  Link below to the review, although I am not sure if there are more measurements in the Hifi News registration area?

https://c2.staticflickr.com/2/1650/25531...9c1e_o.jpg

Stereophile also measured the 140 Pro:

https://www.stereophile.com/content/devi...asurements

Soundstage tested the (as it was then) 130 Pro

https://www.soundstagenetwork.com/index....Itemid=154

Different models, I know, but interesting for comparison.

Does anyone know of any more Devialet measurements that have been published?

[whatmore]

Since the device is not under warranty, does Devialet really need to respond? How many other manufacturers would respond to similar requests?

I don't think there's any indication about it's warranty status. I know when I sold my 120 I was easily able to transfer the balance of the warranty. We don't know what the situation is here

In any event, I was wondering about whether devialet would respond to the measurements. That's got nothing to do with warranty