Will I be missing something?

[Music4Life]

I am planning to purchase a Benchmark DAC1 (non USB). If I connect it directly to my A21 via XLR bypassing the use of a pre-amp, will I be missing something in terms of sound quality?

[Peter Nielsen]

How do you handle volume control?

If you plan to do volume control digitally in your source, you need to make sure that your source is upconverting to 24 bits before volume control and sending the 24 bit data to the Benchmark DAC.

[Alaric]

Without having personal experience with your components , I would imagine eliminating a series of circuits from the signal path can only improve the accuracy of the music. Then you can find out if your pre-amp adds a coloration to the music that you like or dislike. A worthy endeavour either way. :T

[Music4Life]

I guess the Benchmark DAC has a volume control on it.

[jbreezy5]

Only the DAC1-pre and DAC1-HDR versions have a stereo volume control ($1595 and $1895, respectively). The DAC1 and DAC1-USB have volume control for headphone use only ($995 and $1295; respectively).

Regarding upconverting from the source, the Benchmark does the upconverting itself; if your current CD player is being used as a transport, whether it upconverts or not doesn't matter b/c the Benchmark is the DAC. If you are seeking to buy the DAC1 (non-volume control version), you do need to make sure you have volume control on your CD player.

The DAC1 pre has had nothing but raves from every professional who reviewed it. St3r3ophile's review had measurements to back up the claims. I wouldn't be concerned about the quality of the DAC1 pre. Worst case scenario you can purchase directly from Benchmark with a 30-day trial period. :T

[Peter Nielsen]

I guess the Benchmark DAC has a volume control on it.

Indeed it has, but can you live without remote volume control? (That's a convenience I would not want to give up, for sure).

[Peter Nielsen]

Regarding upconverting from the source, the Benchmark does the upconverting itself; if your current CD player is being used as a transport, whether it upconverts or not doesn't matter b/c the Benchmark is the DAC.

As long as the CD player does not alter the data (no volume control etc.) then you are correct. In this case it does not matter.

If you are seeking to buy the DAC1 (non-volume control version), you do need to make sure you have volume control on your CD player.

And that's when upconversion matters! Digital volume control MUST be done in 24-bit domain. If you do it in 16-bit domain, resolution will be lost!

So if you want to do the volume control in the CD player [without significant resolution loss], the CD player must first upconvert to 24 bits. Then the CD player can apply volume adjustment in the 24 bit domain and send the adjusted 24-bit data to the DAC. Thanks to the adjustment being done in 24-bit space, no significant resolution is lost.

When a 16-bit digital volume control is set to MAX level, the data passes through unaltered. However, as volume is lowered the lowest bits will be dropped. If you bring down the volume to 1/2 of MAX you will have 15 bits of resolution, bring it down to 1/4 and you have 14 bits left. Bring it down really low - for instance to 1/256th level, you will end up having only 8 bits left of the original 16 bit data. Not good at all and the degradation in sound quality is anything but subtle at this point.

Doing digital volume control in 24 bits works much better. Now we have 8 additional bits to play with, so at 1/256th of maximum level we still have full 16 bit resolution. For most practical applications this is sufficient. (Most implementations have a volume control that goes in 1% steps, which means the smallest achievable volume level is 1/100th of max level. Consequently full 16 bit performance is guaranteed at all possible volume levels in such devices, provided that the digital volume control is done in the 24 bit domain).

Peter

[jbreezy5]

Indeed it has, but can you live without remote volume control? (That's a convenience I would not want to give up, for sure).

The DAC1-HDR has remote volume control. :T

[Music4Life]

The DAC1-HDR has remote volume control. :T

I am planning to get the DAC1-pre. I want to connect it directly to my A21.