Originally Posted by bigguyca
I've tried all the digital outputs from the BDP-105 to the AV8801 and thus using the DAC's in the AV8801. I've also tried the XLR's, which use the DAC's in the BDP-105, and using the Direct or Pure Direct setting in the AV8801. Using Direct or Pure Direct on the AV8801 with the XLR connections provides by far the best results - the sound is just plain cleaner using the DAC's in the BDP-105.
Originally Posted by goodkat
thank you bigguyca. I also heard similar comments however I am struggling to understand how oppo's DAC can perform better than a flagship pre such as 8801. if audio DAC is not good as oppo then I dont even talk about video processing performance of the 8801. if so is it harsh to think that we are just exaggerating 8801?
First a little clarification:
I use the Direct/Pure Direct setup of the AV8801 with the BDP-105 connected via XLR's to the AV8801 for stereo, typically using CD's in the BDP-105 for a source. I use the DAC's in the AV8801 for multichannel audio associated with video with input via HDMI. I use the AV8801 in this case because I like to use the various audio processing capabilities of the AV8801, such as Audyssey, for video. I find the BDP-105 too limiting as a AV control center. I really like both of these setups.
My use of the term DAC in the above posts is rather sloppy. I really should say the whole DAC system of the BDP-105 or AV8801. This "system" includes many subsystems such as how the digital signals are input, how the whole system is timed, the actual DAC chip, potentially any digital filtering which is done external to the DAC, and the analog circuitry following the DAC chip. There is lots of room here for variation in design and performance in the whole system, even if the same DAC chip is used by each component, which in this case it isn't.
An example of variation: there was a lot of discussion concerning whether the AV8801 uses AL32 multiprocessing in earlier posts. If it uses this processing or similar processing then it does a lot of digital filtering and processing outside of the DAC chip itself.
The actual DAC chips used by the two components seem to be quite different. Marantz I believe uses a TI/Burr Brown chip while OPPO uses a quite different Sabre DAC from ESS technologies. There is an excellent presentation by Martin Mallinson of ESS Technologies from the Rocky Mountain Audio Fest on YouTube concerning the Sabre DAC.
Likely current outputs are used from both DAC chips. How well these currents are converted to voltages has an import effect on audio quality. The picture of the inside of the BDP-105 on the OPPO's website shows that this conversion is done with some rather extensive circuitry employing IC op-amps. I don't know anything more specifically about this circuitry. The Marantz uses HDAM discrete circuits for analog output buffers but again I don't know any other details of their analog design. (Using the XLR inputs to connect the OPPO to the Marantz uses these same output buffers of course.) Based on what is visible of the analog circuitry, the two component carry out the current to voltage conversion using different designs.
The HiFi News (UK) website has a link to the extensive measurements that they perform as part of their reviews. The results from the tests of the BDP-105, which as I remember are from an early 2013 issue, are the best overall that I've found on their website for a stand alone DAC or a CD player. HiFi News hasn't tested the AV8801. They have tested a number of DAC systems (stand alone and in part of other components) at all price levels.
I'm not a circuit designer, nor do I have knowledge of the details of either component, but It seems there are many points in the design of the DAC systems in the AV8801 and BDP-105, including those mentioned above, that could cause variations in performance.