SAM and output power change - Warning!

[Mikeeo]

Dear All,

Today I configured my D400 to half output power ie 200 W. Just wanted to try to see if there was a benefit of lowering power output and pushing the pre amp class A section.
Started without SAM and noticed somewhat 'sweeter' sound which I really liked. BUT then when changing over to SAM something strange happened, at lower volumes so so sound and when increasing slightly more, let's say -15 dB, the bass/mid started to popp and looked like they almost wanted to twist them selfs or turn in side out!!!! Quite brutal gymnastics and no sound just something that would implement that these membranes would soon crack and die. Be careful if testing!
I have the firmware from August (still the name 7.1.1) but I see that 'latest' firmware was issued 23 of December 2014!? Does it have the same name but updates in it? CAN this be the reason why my cones almost flew out of the cabinet? I am now back with my previous config and everything is OK, BUT the sweetness from the 200 W setting slightly missing.

Your kind input to my experience above/Mike

[Confused]

I had a similar thing when I had a demo 250 on loan to try D800 / dual mono. I was having issues with the configurator, I wanted to use one input on the companion, but could not get this to work, I was also having issues with the Companion displaying "Bass On" rather than "SAM On". Anyway, during this time I noticed a strange and large "cone jump" on a couple of tracks. This did not appear to be related to the music, but they were related to a fixed point in the subject tracks. This cone jump occured only on the right hand side speaker. With just my 250, this did not happen. I ultimately purchased a 250 companion, and with this unit the "cone jump" was gone. A configurator issue? A 7.1.1 "version" issue? I have no idea. Thankfully, the issue is gone with my actual companoin & current Configurator settings.

I think my issues look slightly different to yours? But maybe related, maybe a 7.1.1 "version" issue? Who knows!

[Vivialet]

with SAM set to 100% it may happen on certain tracks that you have a "cone jump". But if this happens it happens on both channels for me. As I have configured SAM to only 20% it is not an issue for me.

[Confused]

with SAM set to 100% it may happen on certain tracks that you have a "cone jump". But if this happens it happens on both channels for me. As I have configured SAM to only 20% it is not an issue for me.

This was a very strange looking effect, not the kind of cone movement you would occasionally get with normal music.  For me I am normally using SAM at 100% but no longer have the issue I had in the past with the demo 250.  It was a strange one!

[f1eng]

Dear All,

Today I configured my D400 to half output power ie 200 W. Just wanted to try to see if there was a benefit of lowering power output and pushing the pre amp class A section.

Don't know about the other bits, but the preamp does not have a class A section.
The whole amp has a simple class A amp directly driven by the DAC and directly connected to the speaker terminals, in conjunction with a parallel digital section = ADH. All preamp functions are computed digitally and then sent to the DAC, thence to the ADH amplifier.
Changing the output power in the configurator will have no effect on the class A part, only the digital part.

For what its worth...

[thumb5]

Dear All,

Today I configured my D400 to half output power ie 200 W. Just wanted to try to see if there was a benefit of lowering power output and pushing the pre amp class A section.

Don't know about the other bits, but the preamp does not have a class A section.
The whole amp has a simple class A amp directly driven by the DAC and directly connected to the speaker terminals, in conjunction with a parallel digital section = ADH. All preamp functions are computed digitally and then sent to the DAC, thence to the ADH amplifier.
Changing the output power in the configurator will have no effect on the class A part, only the digital part.

For what its worth...

Moreover, Devialet said that it will only affect what happens when the amplifier reaches the power limit. Below that, it changes nothing.

For what it's worth...

[Mikeeo]

Hi all and thanks for the input!

For what its worth my experiment was useless, good to know

Anyway, I can't understand that popping too as I never had it before on any music material. And why would this happen with a 200 W setting that obviously should be more than enough to drive my speakers!? I blame the configurator or the fact that my 7.1.1 firmware (downloaded in August last year) version differs from the 23rd of December one (it says so on Devialet homepage) I don't know. But things like this worries me a lot and what to expect in the future. Wouldn't be fun to see those bass/mid cones come flying because the movement these cones did was definitely unhealthy so good that I didn't crank the volume more than I did.
Well I am back at 400 W in 6 ohm and no problems what so ever.

/Mike

[Pim]

I might be wrong but what you describe sounds to me that your asking too much from the amplifier. The amp then can't supply a nice sine wave and starts to flatten out; the sine wave doesn't get a chance to come back from low to high quick enough and the end result is almost a DC current. From what I understand, that is how you blow up speakers with an amp that works above its current ability.

If it's true that the (digital) pre-amp is the only thing that changes when you change the output power settings then this should technically not happen. The only way I can see this happen is if the Dev would cut the amount of output transistors used when you cut output power. And if that were the case, the sound could change too because digital volume controls (apparently) sound better when turned up.

I think this is a question for the Devialet team.

[Mikeeo]

I might be wrong but what you describe sounds to me that your asking too much from the amplifier. The amp then can't supply a nice sine wave and starts to flatten out; the sine wave doesn't get a chance to come back from low to high quick enough and the end result is almost a DC current. From what I understand, that is how you blow up speakers with an amp that works above its current ability.

If it's true that the (digital) pre-amp is the only thing that changes when you change the output power settings then this should technically not happen. The only way I can see this happen is if the Dev would cut the amount of output transistors used when you cut output power. And if that were the case, the sound could change too because digital volume controls (apparently) sound better when turned up.

I think this is a question for the Devialet team.

Pim, thanks for the input. My conclusion is that despite cutting the power output to half ie 200W this should not happen (I didn't turn up the volume that much) it must be a configurator glitch that throws the amp into a setting that obviously doesn't work. With 200 W on tap the Raidhos shouldn't present a challenge for the amp. 
Right now I do not have the power to write to Devialet about this and then wait in vain for an answer or if answer comes it will not address my issue. I will stick to my full power setting and old config until I now.

/Mike

[Pim]

I might be wrong but what you describe sounds to me that your asking too much from the amplifier. The amp then can't supply a nice sine wave and starts to flatten out; the sine wave doesn't get a chance to come back from low to high quick enough and the end result is almost a DC current. From what I understand, that is how you blow up speakers with an amp that works above its current ability.

If it's true that the (digital) pre-amp is the only thing that changes when you change the output power settings then this should technically not happen. The only way I can see this happen is if the Dev would cut the amount of output transistors used when you cut output power. And if that were the case, the sound could change too because digital volume controls (apparently) sound better when turned up.

I think this is a question for the Devialet team.

Pim, thanks for the input. My conclusion is that despite cutting the power output to half ie 200W this should not happen (I didn't turn up the volume that much) it must be a configurator glitch that throws the amp into a setting that obviously doesn't work. With 200 W on tap the Raidhos shouldn't present a challenge for the amp. 
Right now I do not have the power to write to Devialet about this and then wait in vain for an answer or if answer comes it will not address my issue. I will stick to my full power setting and old config until I now.

/Mike

So it's a glitch then. Nothing new in Devialet land