View Full Version : Which Burr-Brown DAC is better - PCM1748 (SB3) or PCM1690 (Onkyo 709)?

2011-11-14, 06:18
I'm trying to decide how to connect my SB3 to my Onkyo TX-NR709 receiver - using the analog connection (relying on the SB3 PCM1748 DAC), or using SPDIF (relying on the PCM1690 DAC used by the Onkyo). Any opinions?

2011-11-14, 06:29
1. Figure out if your reciever *really* have a true analog bypass, so that it's not digitizing incoming analog signals to digital .
If it have analog bypass your question becomes relevant (otherwise you should use the digital input) .

2. Try for for yourself, most of the sound quality is the implementation not the DAC chip itself , a DAC is much more than the chosen chip set.

3. Try to do level matched listening it can be so that analog or digital inputs are not equally loud , very small volume differences that are not percieved as louder is interpreted as "better" by our brains.

4. The SB3's volume control is digital use 100% volume on the SB3 , try to use the amps volume control to level out the volume differences.

Lewis Moon
2011-11-14, 07:11
12. Try for for yourself, most of the sound quality is the implementation not the DAC chip itself , a DAC is much more than the chosen chip set.

This ^^^^^^^

I might also add that "better" is highly subjective and depends on everything from one's musical tastes, to your choice of speakers and amp, to the range of your hearing.
Case in point: I LIKE "bright". This is probably because I'm over 50 and my upper range hearing isn't what it used to be. It may also be because I love acoustic jazz and "chamber folk" rather than techno and other bass heavy music.
Finally, your first good DAC will color your opinion of all the others that may come, so do the research (HeadFi is a good start, just read ALL the reviews) and spend the money to get a good one.

2011-11-14, 08:27
Also all outputs are active in paralell, so just conect digital and analog at the same time.

The pcm1690 is a more modern design with the latest tech , but 8 ch . The pcm 1748 an older design but dedicated 2ch.

2011-11-15, 16:26
Thanks for all the comments. I guess listening tests are the best way to compare the two, unfortunately I'm not so experienced in this. Are there any DAC-challenging samples that are recommended to more easily hear the sound quality differences between models?

2011-11-15, 18:41
On thing I cant figure is if there is any real analog pass thru in that reciever I doubth it has it.

It's pure audio mode turns of the video circiuts , that i figured.

if you are going to use any processing including the subwofer output, digital conection is a given.

Most modern av recievers digitise the analog inputs. This means that the Squeezebox analog ouput with ist DAC is going to an ADC ( analog to digital converter ) in the Onkyo and then to the Onkyo's DAC, you want to avoid this, by using a digital input.

Given this recievers advanced eq posibilities I think you are meant to use digital inputs for any serius source, the analog inputs are there to support legacy sources that does not have digital outputs.

The short answer :
On most modern AV recievers you should use a digital input for your squeezebox.

IMO I think most modern design have abandoned the concept of a pure analog path, the volume controll is probably digital too, so you also want to keep the Squeezebox at 100% volume for bit perfect transmission to the digil processor in the onkyo.

2011-11-16, 06:02
Thank you for the detailed answer, it really makes this an easy decision. I will use the SPDIF connection.

2011-11-16, 09:04
it looks a really cool receiver for home cinema .

In recent years those thing gets almost to much functionality .