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Digital vs Analogue volume control
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What are the pros and cons of Digital Vs analogue volume controls?

Are there any downsides for example, in using the digital volume control on the Dacmagic plus?

 

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RE: Digital vs Analogue volume control

digital volume ctrl - less bits - less resolution - more noise. now, if this is going to be audible? maybe with exceptionally sensitive speakers at low volume levers.

analog volume ctrl - the good ones use battery of precision resistors which just limit the signal voltage. but leave the signal shape intact.

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RE: Digital vs Analogue volume control

Can't say I've noticed a difference, though I did get a 651a specifically so that I could control the analogue volume.  Call me -nal...

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RE: Digital vs Analogue volume control

Actually there is a third class, digitally controlled analogue volume controls. These are invariably used in AVRs and can be found in quite a few stereo amplifiers too. They normally use a specialised IC with resistor ladders switched by CMOS analogue switches. They can be extremely good (i.e. sonically benign) and don't suffer from the mismatching associated with even the best conventional potentiometers.

John Dawson

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RE: Digital vs Analogue volume control

Thanks,

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

In the case of digital, I would assume that higher resolution music (above 16 bit) is less susceptible to this potential degradation?

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RE: Digital vs Analogue volume control

John Arcam Dawson wrote:

Actually there is a third class, digitally controlled analogue volume controls. These are invariably used in AVRs and can be found in quite a few stereo amplifiers too. They normally use a specialised IC with resistor ladders switched by CMOS analogue switches. They can be extremely good (i.e. sonically benign) and don't suffer from the mismatching associated with even the best conventional potentiometers.

John Dawson

yeah, I've got something like that in my Pathos. but still, it's analog volume ctrl. only digitally controlled instead of manually or mechanically.

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RE: Digital vs Analogue volume control

Overdose wrote:

In the case of digital, I would assume that higher resolution music (above 16 bit) is less susceptible to this potential degradation?

maybe so, but I'm not sure. never thought about it. never been interested in digital preamps. so, it's now up to you to do some research. Smile

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RE: Digital vs Analogue volume control

It starts here.

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RE: Digital vs Analogue volume control

Overdose wrote:

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

 

A properly designed digital attenuation wont cut bits and is cleaner than an analog pre which adds distortion and colouration. If you want to clean up a signal digital pre's are a good way to go.

 

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RE: Digital vs Analogue volume control

shooter wrote:

Overdose wrote:

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

 

A properly designed digital attenuation wont cut bits and is cleaner than an analog pre which adds distortion and colouration. If you want to clean up a signal digital pre's are a good way to go.

 

 

+1

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RE: Digital vs Analogue volume control

busb wrote:

shooter wrote:

Overdose wrote:

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

 

A properly designed digital attenuation wont cut bits and is cleaner than an analog pre which adds distortion and colouration. If you want to clean up a signal digital pre's are a good way to go.

 

 

+1

+1, but

what does properly designed means. if the OP want s to choose a properly desigend one, what to look for?

My understandign is that digital vol control to be 'near perfect' should be high bid-depth processing i.e. 24 bit or higher. sometimes (always?) dithering is also used which I understand is good too. 

right?

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RE: Digital vs Analogue volume control

Overdose wrote:
Are there any downsides for example, in using the digital volume control on the Dacmagic plus?

Love him or hate him*, Ken Rockwell measured the volume control at -20dB, -40dB and -60dB gain for distortion and found it performed very well in this regard...

http://kenrockwell.com/audio/cambridge/dacmagic-plus.htm

Do an 'edit', 'find' for "volume control introduces" (without the speech marks) to find the relevant bit quickly.

*Sorry JD, I know you hate KR (as do I ), but he does answer this specific question of the OP's.

 

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RE: Digital vs Analogue volume control

AlmaataKZ wrote:

busb wrote:

shooter wrote:

Overdose wrote:

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

 

A properly designed digital attenuation wont cut bits and is cleaner than an analog pre which adds distortion and colouration. If you want to clean up a signal digital pre's are a good way to go.

 

 

+1

+1, but

what does properly designed means. if the OP want s to choose a properly desigend one, what to look for?

 

 

You need a dithered digital attenuation.

 

 

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RE: Digital vs Analogue volume control

AlmaataKZ wrote:

busb wrote:

shooter wrote:

Overdose wrote:

So in essence, digital control can affect resolution and potentially quality, analogue control, much less so?

 

A properly designed digital attenuation wont cut bits and is cleaner than an analog pre which adds distortion and colouration. If you want to clean up a signal digital pre's are a good way to go.

 

 

+1

+1, but

what does properly designed means. if the OP want s to choose a properly desigend one, what to look for?

My understandign is that digital vol control to be 'near perfect' should be high bid-depth processing i.e. 24 bit or higher. sometimes (always?) dithering is also used which I understand is good too. 

right?

 

I tried to edit my post immdiately after it appeared but it got lost in the ether probably 'cos it got quoted. so:

 

My previous amp (PrimareI21) had a digitally controlled analogue volume control that had 1dB increments. It worked fine but the jump from 0 to 1 was too coarse. I fancied a motorised volume control (with a little red LED!) but never actually owned one such as on the Roksans.

My audiolab M-DAC has a digital domain volume control, again with 1dB steps but works extremely well where the difference between -80 (off effectively) & -79 is nice & fine. A friend's Moon i1 has a motorised volume that makes a mechanical sound whilst being used. My M-DACs volume allow me to feed its output into the "Direct" input of my amp with its purely analogue volume control set at max but is still effective though never now used. My next upgrade will be to a power amp with XLR inputs thus bypassing my present setup's volume control (all my inputs are digital).

The M-DAC IS working with 32bit depth (IIRC but I maybe wrong in which case only 24bit) which is why I'm not bothered about using passive attenuators between it & any future power amp. I would agree that 24bit depth when manipulating volume levels is probably not a bad idea. Some may argue that the Red Book standard of 16bit is good enough but when editing (volume adjustments included), 24bit depth allows the integrity of 16bits to be left intact.

 

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RE: Digital vs Analogue volume

oldric_naubhoff wrote:

digital volume ctrl - less bits - less resolution - more noise. now, if this is going to be audible? maybe with exceptionally sensitive speakers at low volume levers.

analog volume ctrl - the good ones use battery of precision resistors which just limit the signal voltage. but leave the signal shape intact.

 

Volume levers? That's a brilliant idea! Let say a foot long, chrome with nice polished brass knobs! Perhaps you could approach Chord electronics to see if they would run with the idea? Dead cool! :poke:

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RE: Digital vs Analogue volume control

AlmaataKZ wrote:

+1, but

what does properly designed means. if the OP want s to choose a properly desigend one, what to look for?

My understandign is that digital vol control to be 'near perfect' should be high bid-depth processing i.e. 24 bit or higher. sometimes (always?) dithering is also used which I understand is good too. 

right?

I think digital volume control has to be well designed...take the Wadia volume control for example. It has 2 good properties:

1. The digital input is first upsampled to 24 bits, then resolution above 16 bits is not sacrificed except at low volume levels.

2. So that you can always play your music at optimum volume level (> 70%), it has configurable attenuation on the outputs which feed the power amps directly. You adjust these so that you can operate the volume in the 70-100 range for typical listening.

The Wadia volume has 100 steps, each step is 0.5db increment. So volume of 1 is essentially -50db.

This from the Wadia web pages:

Digital Volume Control (with adjustable maximum output level)
Since 1992, Wadia has continued to refine the first audiophile-quality digital volume control. It remains the only volume control that delivers the theoretical advantages of volume control in the digital domain. Although less sophisticated digital volume controls can sacrifice resolution, Wadia's volume control with adjustable maximum output level can be optimized to match a wide range of systems, ensuring greater than 16-bit resolution over the majority of the volume range.

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