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Vrms - how does it work exactly?
#1
In the Devialet Configurator, I've noticed some inputs have this Vrms setting. can someone explain, in layman terms,  how this works and what my real world results would be if i made changes to this setting? I'm assuming this would raise or lower the volume (gain) to my speakers at a given level (like a boost so to speak).

does the rms setting need tomatch the Speakers or the input device? curious if you guys use this setting and your outcome. 



Maximum input RMS level: the amplifier gain is adjusted to make it match the maximum RMS voltage at the speaker output (Factory Setting: 2 VRMS)

An excessive value requires to push the volume control higher and needlessly prepares the amplifier to high power demands, with slightly increased energy consumption and heat dissipation: this is especially the case if you connect the earphone output of a portable player (whose output voltage is limited to protect your ears) without choosing the corresponding low value preset; a too low value leads to clipping of the most dynamic records.
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#2
i should add that playing around with some old bookshelf B&W's that i have until my new Focals arrive, i have noticed that some inputs require me to increase the volume to get the same db levels.

for instance, wireless streaming using my Apple TV's toslink requires me to turn up the volume more to get my "normal" listening level. same for my Oppo cd/dvd player that i am using both the RCA/Analog out and SPDIF digital connection. one input is lower than the other.

so I'm trying to understand how to tweak my D200 to compensate accordingly.
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#3
Hello, the input voltage (also often input sensitivity) actually specifies only the level, which the device internally regards as 0 dB. Often values are also given in dBu or dBv. 0 dBu corresponds to 0.775 V, 0 dBv to 1 V. 0 dBv therefore corresponds to approx. 3 dBu. The standard radio signal level is 1.55 V, ie approx. 6 dBu or 3 dBv (XLR).
At 0db, the amplifier should reach the specified output power.
Please refer:
http://www.sengpielaudio.com/calculator-db-volt.htm
Devialet 220Pro/CI, B&W 802 D3, Linn Klimax DS/Katalyst, Burmester 089 CD, Melco N1ZS/2A + D100, Cable Audioquest (NRG-10,Diamond,K2,Yukon,Coffee etc.), iPad-Pro, KECES P8 Dual, Tidal HiFi
IsoTek: 2 x EVO3 Genesis One, EVO3 Titan One, EVO3 Syncro, EVO3 Synchro Uni.                                                                                                                                                             Germany / Bavaria
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#4
Thanks for the reply, but I must admit I feel out of my league trying to comprehend your explanation or how it equates to the Vrms setting in the devialet configurator.

Regards,

Mike
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#5
(17-Dec-2018, 23:42)mmorrison55 Wrote: In the Devialet Configurator, I've noticed some inputs have this Vrms setting. can someone explain, in layman terms,  how this works and what my real world results would be if i made changes to this setting? I'm assuming this would raise or lower the volume (gain) to my speakers at a given level (like a boost so to speak).

Broadly speaking your assumption is right.  The max input level stated in Vrms ("root mean square Volts") is a measure of how big the input signal needs to be for the amplifier to produce its full power output.  As you adjust the max input level it changes the internal gain of the amplifier.

If you have connected something like (say) a CD player to a line-level input, then the CD player might produce for example 1 Vrms when the CD is playing at its loudest.  If the Devialet is configured with its input level set to 1 Vrms then it will produce its full output when the CD is at its loudest.  If you increased the Devialet's input level to 2 V rms then it would not produce full output when the CD was playing at maximum; on the other hand if you decreased the input level to 0.5 Vrms then the amplifier would reach its maximum power before the CD was playing at full volume, and might "clip" (run into a temporary overload) when the CD was at full volume.  You'd see that on the Devialet display as it goes orange or red (I can't remember) when the input signal gets high enough to put it into overload.

To summarise, a bigger number in the Vrms field means that the amp is less sensitive and will sound quieter for a given input level.  A smaller number makes the amp more sensitive so it will sound louder for a given input.

(17-Dec-2018, 23:42)mmorrison55 Wrote: does the rms setting need tomatch the Speakers or the input device? curious if you guys use this setting and your outcome. 

The max input level setting should be chosen to match the input device -- in particular, its output level which will normally be part of its specification.  Typically most analog sources other than phono cartridges have so-called "line level" outputs, which are usually around 1 Vrms at full volume.  Phono cartridges have much lower output levels, usually a few hundred microvolts (μV) or several millivolts (mV), which you'll see if you configure the phono inputs.  On the whole it's better to start with higher numbers in the configurator's Vrms field (lower sensitivity) and then reduce the number (increase the sensitivity) if you need to, being sure to avoid clipping.
Roon (Mac Mini), Wilson Benesch Full Circle, Sonos ZP90 (Cullen modified), Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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#6
Thanks Ian, this helps explain the setting quite a bit.
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