250 pro - "ploc" in the speakers during amp start or shutdown

[zaienk]

Hello,

I got my new 250 pro, I also have a devialet 120.
When I turn on my 250 pro, during the initialisation, it makes a little "ploc" sound in the speaker. I got the same when the amp turn off.
I don't have this "ploc" sound with my devialet 120.
After some more test, I realised that on the devialet 120, i can also hear a little "ploc" coming from the twitter of my speakers (B&W CM10S2) when I put my hear on it. But with the 250 pro, I can actually hear it when I sit in front of my speakers on the sofa which is not the case with the devialet 120 as I never noticed it previously and it was my main amp.
Also, by putting my hear on the twitter when connected to the 250 pro, I heard that I have more "back noise" (when amp on and no source connected) in the right channel than in the left channnel with a little more harsh noise. I don't have this "back noise" difference between each channel in the twitter with the devialet 120.
Maybe I am a bit paranoic, but I would really appreciate your feedback if you already experienced it.
I opened a ticket to devialet and will see what they respond.

Sorry for my english, I'am french

Kind regards

[Axel]

Hi, and welcome to DC!
My 440 Pros make a slight noise when they are turned on and off. First one speaker, then a split second later, the other one. I can hear this clearly from the listening position, but it’s not loud, and I’ve never worried about it.
I’ve never heard anyone complain of noise coming from a speaker when there is nothing playing though. In fact it’s the only amp I’ve ever owned that is completely silent in this respect.
Does it matter which input you are using when you hear this “back noise”?
If I understand correctly, both the 250 and the 120have the "back noise"?
This , I think, is highly unusual and I wonder whether it might have something to do with your power supply. Do you have a bad mains supply?
Does it make any difference to your overall sound quality, is the hiss audible when playing music? If the noise increases when you turn the volume up, then I would worry.
Are you living out in the sticks far away from the nearest mains transformer?
I hope you get it sorted out.
P.S. your English is very good. Better than some English people!

[ogs]

Hi, welcome to the forum!
I also have a sound like this from my 250. Stronger in the right channel, but weak enough to ignore. My amp was originally a D-Premier and was completely silent. The ON/OFF 'ploc' came with one of the upgrades, the one before 'Pro' I think.

[zaienk]

Hi Axel

Thank you for your feedback!

Does it matter which input you are using when you hear this “back noise”?

=> No

If I understand correctly, both the 250 and the 120have the "back noise"?

=> 120 has a little back noise but is more quiet than 250 pro and 120 doesn't have a different backnoise between channel.
The backnoise with the 250 pro is stronger on the right channel, but still you have to put your ear on the twitter to hear it.

Do you have a bad mains supply?

=> No

Does it make any difference to your overall sound quality, is the hiss audible when playing music?

=> I have to listen and make comparaison between my D120 and my D250 pro to avoid any psychological effect. 

If the noise increases when you turn the volume up, then I would worry.

=> It doesn't not increase

Are you living out in the sticks far away from the nearest mains transformer?

=> No

[zaienk]

Hi Ogs

Thank you for your feedback! So you also have the on/off "ploc" and a little backnoise which is higher on the right channel, it is good to know that I am not an "isolate case" and that it has been introduced with the new models.
The 250 pro I have has been upgraded from D Premier.

[ogs]

@zaienk hi, I have no noise in any of the channels, just the little 'ploc' when the amp turns on or off. It does not change with volume setting.

[zaienk]

@ogs ok so when you wrote "I also have a sound like this from my 250. Stronger in the right channel, but weak enough to ignore" It was about the ploc?

So you can not hear any noise coming from the twitter of your speaker (even a little "breath") when you put your ear straight on it while amp is on and not playing any music ?

[ogs]

Yes, only the 'ploc'. No noise or hiss from the speakers with my ear close (I think. I am travelling at the moment so I can not double check this...) I can not hear any noise from the listening seat.

[thumb5]

The switch-on/off noise you hear could perhaps be the same thing I reported here: https://devialetchat.com/showthread.php?tid=4020.  I've learned to live with it...

[ogs]

It is very similar to your description, yes. I only hear it on startup/shutdown, not when switching inputs. I have not played any DSD yet so I wouldn't know about that