Would a DAC Improve my sound?

[Bill_Janssen (Wigwam wool socks now on asymmetrical isolation feet!)]

@Mike_O_Neill

Does your AV amp have a “pure” mode , they often do

This leaves a signal unmolested just acting as an amp with no DSP

Yeah, my Onkyo TX-8050 has a pure mode, too. But I found the schematic (it’s linked in my “Confused about” thread) and read it. Turns out even in pure mode the volume control – the digital volume control – is still engaged, so it still does this trick of converting the analog signal internally to digital, then adjusting the volume, then using its internal D/A to take the digital volume-controlled signal and convert it to analog again.

This has been bugging me ever since I found the schematic. So I finally broke down and ordered the parts for one of these nCore power amplifiers so I can get rid of the Onkyo. Still going to use digital volume control, but this time in the DAC, where it belongs.

[Peter_Rustin]

Also pure mode bypasses room correction and subwoofer

[Jacques_Distler]

@Bill_Janssen

So I finally broke down and ordered the parts for one of these nCore power amplifiers so I can get rid of the Onkyo.

FWIW, audiophonics.fr sells a completely assembled version of that amp for €391 (ex VAT). That’s pretty competitive with the DIY cost (but lacks the excitement of plugging in the DIY version for the first time and seeing whether you wired the mains connection correctly )

[Bill_Janssen (Wigwam wool socks now on asymmetrical isolation feet!)]

@Jacques_Distler

a completely assembled version of that amp

Yes, looks like a good layout, power switch on the front.

AUDIOPHONICS MPA-S250NC XLR Power Amplifier Class D Stereo Ncore NC252MP...

[Jacques_Distler]

Actually, 2 power switches.

• A standard rocker switch on the back, and
• a push-button with LED on the front.

There’s also a 12V trigger, if you have a preamp you want to control it with.

[Jacques_Distler]

@Bill_Janssen

Turns out even in pure mode the volume control – the digital volume control – is still engaged, so it still does this trick of converting the analog signal internally to digital, then adjusting the volume, then using its internal D/A to take the digital volume-controlled signal and convert it to analog again.

FWIW, I am not sure that’s quite correct.

IIUC, the volume controller in that receiver is a Renesas R2A15908SP. It’s not an DA/AD converter. Rather, it’s a microprocessor-controlled resistor ladder.

A description of such beasts can be found, e.g., here (in the section entitled " Single Chip Analog AVR LSI"). I don’t know anything about the quality of that particular chip, but similar microprocessor-controlled resistor ladders are used for volume control in rather “high end” preamps.

[Peter_Rustin]

Bah! Damn you avr!

[Jacques_Distler]

I seriously doubt that you will ever be able to tell the difference between 96 and 192 kHz sample rates.

OTOH, @Bill_Janssen’s Hypex NC252MP amplifier is way better than the amplifier section of your AVR. If you have hard-to-drive speakers, better amplification might be a worthwhile upgrade.

If your speakers are not particularly problematic, then I would just relax and enjoy the music.

[Bill_Janssen (Wigwam wool socks now on asymmetrical isolation feet!)]

@Jacques_Distler

FWIW, I am not sure that’s quite correct.

It’s entirely possible that I am wrong. I haven’t read schematics for a living since 1984, and the whole LSI scene was quite different back then. I’ll take another look at them. I was a bit surprised that they didn’t use some digitally controlled op-amp volume control, like TI’s PGA2320. The Renesas part would make sense.

@Jacques_Distler

A description of such beasts can be found, e.g., here (in the section entitled " Single Chip Analog AVR LSI ").

This is a great resource! Thanks for sending it along. I skimmed it last night, and I’ll read it more carefully today (Super Bowl permitting, of course). Unfortunately, the most interesting link in Part II seems to be broken, a link to a table of details about the various AVRs and Pre/Pros.

[Jim_F (Minimalist)]

I think 24/192 sounds better than 24/96, but it’s probably my imagination.

[Jacques_Distler]

@Bill_Janssen

I’ll take another look at them. I was a bit surprised that they didn’t use some digitally controlled op-amp volume control, like TI’s PGA2320. The Renesas part would make sense.

I’ll be interested to hear your findings, as I have a bit of a vested interest. Currently, my volume control is a Renesas R2A15220FP.

[Benjamin_Pitot]

You’re right, I am using the Woo Audio Fireflies WA7 headphone amp, it has a good internal DAC but bypassing it with the Ares II brings a warmer sound with its R2R technology.