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Passthrough output power loss?
#11
setting to a -15dB default is a safe setting for all users, due to output level mismatches between an almost infinite number of components. Imagine the problem if they set it to 0, and somebody blows up their speakers ! Increasing it is then a users (conscious) decision, so it makes perfect sense to me.
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Aurender X100, Audiophilleo, Devialet 200, Verity Audio Parsifal Ovation Monitors
Leiden, the Netherlands
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#12
I suppose so but the point of a passthrough is just that. The signal shouldn't be touched in the pre stage.

Most components with home theatre bypass allow the full signal to passthrough to the output stage without touching it.

Anyway, no matter my issue is fixed albeit I never noticed the heat issue until now. Bypass most definitely runs warmer than the other modes.


Sent from my iPhone using Tapatalk

Digital: ROON on Synology & SONOS Connect
Analog: Marantz TT-15s1 - ClearAudio Virtuoso MM Wood

Main: Devialet D250 - KEF LS50
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#13
(25-Apr-2015, 15:05)adhesiv Wrote: Bypass most definitely runs warmer than the other modes.

Last night after watching a movie followed by a few episodes of Better Call Saul I thought I'd check the temperatures... highest reading ever: 67C on the Companion Class A with most of the other readings in the low to mid-60s!  Confused

I should also say that this was on firmware 7.1.3 since I wasn't able to use 8.0 due to the weird rumbling sounds when selecting bypass mode. 

Guillaume
Industry disclosure: UK distributor for Shunyata Research

220 PRO, totaldac d1 server with additional external power supply, totaldac d1-seven, Echole PSU for Totaldac, Wilson Audio Sasha 2, Shunyata Research cables, Shunyata Hydra Alpha A10 + DPC-6 v3, Various Entreq ground boxes and cables, Entreq Athena level 3 rack, 2 X SOtM sNH-10G with sCLK-EX + 10MHz Master Clock input + sPS-500 PSU, i5 sonicTransporter w/ 1TB SSD

UK
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#14
I am also concerned in view of the high temperatures of the bypass mode (especially as watching movies / tv series lasts a few hours a day).
As this affects many users and most likely will reduce the lifetime of the Devialet this should really be addressed by Devialet.
Does anybody know if they are already investigating this?
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#15
(08-Oct-2015, 10:57)markush Wrote: I am also concerned in view of the high temperatures of the bypass mode (especially as watching movies / tv series lasts a few hours a day).
As this affects many users and most likely will reduce the lifetime of the Devialet this should really be addressed by Devialet.
Does anybody know if they are already investigating this?

This has already been addressed with the addition of DPM in the 8.x.x firmware updates.

I also note that some people adjust the pass through gain in the Configurator, presumably with an associated tweak to the output of the feed, say from a surround sound decoder pre-out.  This can also help reduce temperatures, assuming sound levels are kept out of the clipping range.
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#16
(08-Oct-2015, 12:56)Confused Wrote:
(08-Oct-2015, 10:57)markush Wrote: I am also concerned in view of the high temperatures of the bypass mode (especially as watching movies / tv series lasts a few hours a day).
As this affects many users and most likely will reduce the lifetime of the Devialet this should really be addressed by Devialet.
Does anybody know if they are already investigating this?

This has already been addressed with the addition of DPM in the 8.x.x firmware updates.

I also note that some people adjust the pass through gain in the Configurator, presumably with an associated tweak to the output of the feed, say from a surround sound decoder pre-out.  This can also help reduce temperatures, assuming sound levels are kept out of the clipping range.

DPM I'm sure is a nice feature. Though I think temperatures are still quite high when using bypass - and watching movies / series a few hours.
What tweak are you refering to? Sounds interesting Smile
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#17
The tweak? Set the output of your surround amp / processor for the front speakers (output to Dev) to say +8dB, you can then drop the pass through gain on the Dev by -8dB. On my surround set up, with the surround processor volume set to -12dB, the whole system is stupidly loud, so no need to go higher. The Devialet does not clip, but running reduced gain it does let the amp stay cooler.

More recently, I have stopped using the pass through mode, and have the Devialet surround input as a normal input with volume control enabled. This works well for me, watching a movie the Devialet volume is usually set to about -6dB to -8dB, plus this allows you to adjust the main channel volume slightly to suit the particular surround mix of whatever you are watching. The correct balance varies a lot from film to film I think, so a degree of easy adjustment is useful. I know that this can be done using the settings in the surround processor, but diving though menus and sub-menus is a pain, tweaking the Dev's volume is easy.
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#18
Wow - got a great and detailed answer from Devialet support. That also brings some new insights:
==
For a given audio material, between its stereo and its multichannel version, the overall audio energy is either split into 2 or 5.1/7.1 channels. Thus, the energy per channel is always lower on a multichannel programme. That is why, on most AV amps, the average analog voltage level found on the stereo preout is much higher than the average voltage level found on the 5.1/7.1 preouts. The difference can easily reach the 12-20dB range. A CD player commonly outputs 2.0Vrms while reaching 0dBfs. So do analog 2.0 preouts. But 5.1/7.1 preouts feature much lower levels, say 0.5Vrms for 0dBfs. Remember that 0.5Vrms on 7.1 channels deals with more global energy than 2.0Vrms on 2 channels only. Input sensitivity on our analog inputs must be adjusted in order to take those differences into account. If not adjusted, useless operating margins will be provided in our units, in order the ADC input stage to never saturate.
Please check your Denon documentation and determine its output level on 5.1/7.1 analog preouts. Once known, adjust it via our online configurator 'Maximum Level' slider.
Why are our units hotter in bypass mode ? Under normal circumstances, without bypass mode, and especially with digital inputs, the instantaneous digital level of the incoming content is monitored and we do perform minimal ideal biasing conditions, leading to the minimal amount of wasted heat without any compromise on distorsion nor compression of the incoming material.
With bypass mode, the output power isn't known anymore, as our units do not control the output levels anymore. A silent signal or a full amplitude signal will lead to identical bias dissipation, as 99% of other amps do.
Bad input configuration will lead to increased bias and therefore useless heat. If ever we had a 5.1/7.1 amp based on our various technologies, you'd be surprised on how cooler it would run compared to most AV amps.
You really shouldn't worry about temperature.
Our units, although being beautiful objects, are industrial+ grade equipments with most components capables of thousands hours of continuous operation above 100°C and internally limited by us to 70°C, allowing an extremely comfortable thermal margin and therefore component lifetime. There are 10 thermal sensors in each product with thermal shutdown in case maximum temperature is reached. What you experience in bypass mode is way easier than the thermal test run at the factory during production. Again, no risk for your amp.
Now to conclude, we need your configuration file plus all the values of the adjustable parameters (SAM, RAM, tone control, filters, ICM, DPM etc...) in order to investigate this 'power loss' issue. We'd also need the software version running on the amp and the temperatures when this loss of power is experienced. It could be a software/configuration issue. By the way, we'd advise not to use SAM in bypass mode, especially with a subwoofer in the setup. The reason is that the additional bandwidth provided by SAM will pollute the bass management of the AV amp.

==
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#19
Very interesting information, thanks for posting.

If Devialet could/would provide answers with that level of detail and careful explanation to all support queries, that would be first class.
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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#20
(09-Oct-2015, 08:57)thumb5 Wrote: Very interesting information, thanks for posting.

If Devialet could/would provide answers with that level of detail and careful explanation to all support queries, that would be first class.

I concur! An excellent response.

Guillaume
Industry disclosure: UK distributor for Shunyata Research

220 PRO, totaldac d1 server with additional external power supply, totaldac d1-seven, Echole PSU for Totaldac, Wilson Audio Sasha 2, Shunyata Research cables, Shunyata Hydra Alpha A10 + DPC-6 v3, Various Entreq ground boxes and cables, Entreq Athena level 3 rack, 2 X SOtM sNH-10G with sCLK-EX + 10MHz Master Clock input + sPS-500 PSU, i5 sonicTransporter w/ 1TB SSD

UK
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