A DAC into a DAC?


Help me understand the signal path and clarify my options…

A little background: my digital source feeds into a pre-pro which I am using as a pre-amp only. It has Burr-Brown 24/192 DACs, (I don’t know which ones, nor can I bypass them). I am converting to a 2 channel system, which would include a new DAC, but I believe my pre-pro is limiting my options if I keep it in the chain.

Here’s my understanding: If I insert (between my source and the pre-pro), a new DAC that’s SUPERIOR to the pre-pro’s DAC, I assume that the pre-pro would limit or degrade the SQ of the new DAC. Correct? Is feeding the signal from the pre-pro an option in this case?

And if I insert some INFERIOR DAC into the chain, I assume that I couldn’t hear it at all, (preventing A/B comparisons). Another waste. Correct?

With my current set up, it seems like either I would have to abandon the idea of A/B comparisons of any new DACs OR that if I wanted to A/B, I would need to commit to a DAC that also functions as a pre-amp, or else buy a new pre-amp, which I don’t want)… Am I on the right track?

Thanks!
Michael
mkh1099
Keeping everything digital should just pass the digital signal through from your source to the dac. The data will only get decoded once.

If you are using 2 channel only and the pre/pro is staying on as the preamp, just run the source to the dac to a pair of analogue inputs in the prepro.

You could compare the 2 dacs and see what you like best.
What brand and model pre/pro are we talking and the same for the outboard DAC?

If you have a superior outboard DAC, it will convert to analog and then enter your pre/pro. If the analog stage of the pre/pro is of low quality, then it may hamper the sound quality.

You probably should be a little more specific to give us a better idea of how to better answer your questions.

I have a Cambridge Audio 840C player/DAC that is of pretty high quality that goes in to an also pretty high quality NAD T175HD pre/pro. I use the CA 840C's DAC to convert and upsample(24/384)a Pandora stream from my Samsung TV and it does a better job than the T175HD's DAC. On the other hand, when I play redbook CD's, I mainly use the 840C as a transport only selecting the "pass through" setting with no upsampling and let the T175HD do the D/A converting.

Bill
"If I insert (between my source and the pre-pro), a new DAC that’s SUPERIOR to the pre-pro’s DAC, I assume that the pre-pro would limit or degrade the SQ of the new DAC. Correct? Is feeding the signal from the pre-pro an option in this case?"

ANY preamp will add some distortion, compression and noise to the analog signal, but you need some way of controlling volume and achieving a low-output impedance drive to your amps in order to get decent dynamics.

Most decent DACs (over $1K) will outperform the DAC in a SS processor. All you need to do is feed the analog outs from the DAC to the SS proc and control volume with the SS proc. This will probably improve the SQ over the SS Proc. internal DAC, but you have the preamp adding noise and distortion.

A better solution is to get a DAC with good output drive and replace the SS proc. with a transformer-based linestage like a Music First.

Another option is to get a DAC with good output drive and a good volume control technology and replace the SS proc. This is what I do. In order to insert other analog sources such as home theater or vinyl, I use a Final Drive after the DAC and before the amps.

Final Drive:

http://www.empiricalaudio.com/products/final-drive

Steve N.
Empirical Audio
Thanks for your responses so far!

The Pre-pro is an Onkyo PR-SC885, and I assume it's of pretty good quality with those Burr-Brown's.

As for the outboard DAC, I am hoping to A/B several, and I haven't bought one yet. But the Wyred 4 Sound DAC2 is at the top of a short list.

Michael