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Hopefully this is the correct forum for this question. I use an Oppo BDP 105 as the source for a 2-channel only system into a Vincent integrated amp. I had always used the volume of my amp previously, usually quite low since it's a beefy amp of 150 watts per channel, and had the Oppo volume fixed at 100%.

Recently, I decided to try the digital volume on the 105, usually ends up between 65-85 generally for the volume level I want, and have left the volume control on my amp at a little under half-way, about 11 o clock position.

It seems like it sounds better in this configuration, maybe I'm imagining , not sure but bass seems to be somewhat punchier etc.

What is others experience with this? Am I really getting benefit by leaving the volume up on my amp much more so than previously? I guess I've heard in the past that an amplifier really doesn't "open up" and display it's power until the volume is cranked up somewhat.
 

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The purpose of the volume controls on the input components is to match spl so that you don't have to adjust the main volume when you switch inputs. I would set the oppo so that it produces about the same volume level as whichever other input source you use commonly.
 

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Quote:
Originally Posted by purplerocks  /t/1521875/digital-volume-control-on-source-vs-integrated-amp-volume-control#post_24463367


Hopefully this is the correct forum for this question. I use an Oppo BDP 105 as the source for a 2-channel only system into a Vincent integrated amp. I had always used the volume of my amp previously, usually quite low since it's a beefy amp of 150 watts per channel, and had the Oppo volume fixed at 100%.

Recently, I decided to try the digital volume on the 105, usually ends up between 65-85 generally for the volume level I want, and have left the volume control on my amp at a little under half-way, about 11 o clock position.

It seems like it sounds better in this configuration, maybe I'm imagining , not sure but bass seems to be somewhat punchier etc.

What is others experience with this? Am I really getting benefit by leaving the volume up on my amp much more so than previously? I guess I've heard in the past that an amplifier really doesn't "open up" and display it's power until the volume is cranked up somewhat.

The usual convention is to have the earlier volume controls in the component chain as high as possible without distortion, which you roughly seem to be following.


The reason to leave the earlier volume controls as high as possible is to minimize noise.


It is possible that the fixed outputs of your 105 were causing input stage distortion in the sequel equipment, and reducing its volume allows the later stages to avoid distortion. I don't even now if the Vincent equipment has input stages. No schematics to analyze. Just speculating.
 

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A true digital volume control truncates bits to control volume and loses resolution when volume is reduced.


I very much doubt that the superbly engineered BDP-105 is set up that way.


It is more likely using a resistor "ladder network" attenuator which is digitally SWITCHED. That is an analog volume control, NOT a digital volume control.


The main disadvantage of turning the volume way down on a potentiometer volume control (which the amplifier may have) is that the two channels may have slightly different gains at the lower settings.
 

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Quote:
Originally Posted by commsysman  /t/1521875/digital-volume-control-on-source-vs-integrated-amp-volume-control#post_24477132


A true digital volume control truncates bits to control volume and loses resolution when volume is reduced.


....

This statement is not correct. There are no bits truncated. There is no loss of resolution.
 

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Quote:
Originally Posted by commsysman  /t/1521875/digital-volume-control-on-source-vs-integrated-amp-volume-control#post_24477132


A true digital volume control truncates bits to control volume and loses resolution when volume is reduced.

Simply not true of even mid-grade equipment let alone top quality products like Oppo produces. Truncating bits is one of those "no-nos" that everybody learns about in his DSP classes.


Quality digital volume controls are implemented by digital multiplication, not truncation. Truncation would force the volume to be reduced in 6 dB steps when 0.5 is a reasonable goal.


The cause of this pervasive audiophile myth is a lack of understanding of computer arithmetic. In general when two integer numbers are multiplied on a computer, the result has as many bits as the sum of the two numbers being multiplied. So the product of for example two 24 bit numbers is a 48 bit number. This convention which dates back to the mainframe days, is generally followed by both microprocessors and DSPs.


ESS's DAC technology accepts inputs that are 32 bit numbers and scales the operation of the chip in the analog domain as the input signal decreases. This is described here: http://www.esstech.com/pdf/digital-vs-analog-volume-control.pdf on the page labelled


"D vs A Volume 16 of 39"
Quote:
I very much doubt that the superbly engineered BDP-105 is set up that way.

The BDP 105 obtained its excellent volume control technology from its ESS DAC chip. This is common these days - the DAC chip includes one or more digital volume controls that exploit the on-chip connection to the actual DAC functionality.
Quote:
It is more likely using a resistor "ladder network" attenuator which is digitally SWITCHED. That is an analog volume control, NOT a digital volume control.

Good description of the operation of all modern AVRs in every price range, but the BDP-105 marches to a different drummer. In my estimate it is a half-generation or more ahead, technologically. AVRs tend to be a bit backward because skeptical audiophiles keep demanding analog inputs that are kept purely in the analog domain, "Pure Analog", etc.


The BDP 105 is shaping up as a viable alternative to Surround Processors. It has bass management and a full complement of decoders and signal processors. Compare its ca. $1300 street price to things like


Onkyo PR-SC5509


Yamaha AVENTAGE CX-A5000


NAD T 187


Marantz AV8801


and you save like 1 $large or 10 Benjamins, or more.
Quote:
The main disadvantage of turning the volume way down on a potentiometer volume control (which the amplifier may have) is that the two channels may have slightly different gains at the lower settings.

That's true and its a major hassle that costs significant money to get even halfways right. Other problems include the degradation of the resistive element and the contact that slides on it with use and time. An inherent problem is that the the analog stage that follows the potentiometer needs to have very low inherent noise.
 
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