Audiophile Tech Avengers, Assemble! Khadas Tone Board and Elac integrated amp question

Okay, so here is my question.

I have a NUC running ROCK, going over Wi-Fi to a RPi 4. Everything works great. Up until today, I fed the RPi 4 into a Khadas Tone Board via USB and then RCA analog cables out of the Khadas into the analog inputs on the Elac integrated amp (EA101EQ-G). Speakers are Elac Debut 6.2. It all sounded pretty good to my ears.

But you all know that pretty good is never good enough. So I decided to connect the RPi USB output directly to the USB input on the Elac integrated amp. I sat back, thinking - this is always just hogwash. Audio woo. It will sound identical.

Holy cow. It didn’t. Not even close. The direct connection via USB from RPi to Elac amp sounded far better - deeper, richer, more umph - just everything. And I turned off all DSP, made sure volume was the same, etc. I really don’t think it’s placebo.

So here’s my question. It looks like the Elac integrated amp “internally upsamples” analog inputs to 96khz. So was I double DACing by using the Khadas Tone Board into the Elac integrated amp? (There is no “pure direct” setting like there is on Yamaha amps, for example). Was that why it didn’t sound as good as using the Elac’s internal DAC? Or is the DAC chip in the Elac integrated amp just better? What the hell is “internal upsampling” anyway?

Any advice or information from you all would be super helpful. In case you’re wondering, here is the source where I read that the Elac amp "internally upsamples: http://www.audiostereo.ro/ELAC%20reviews/elac_element_ea101eqg_rev-hifinews.pdf

Thanks in advance!

Yes.

Probably. You convert to analog on the Tone Board, then back to digital with the DSP chip in the Elac. Two extra conversions, and something is likely lost in both of them. Just run the digital signal into the Elac.

Thanks!

This confirmed what I expected. I appreciate it.

Looks like I might have a Khadas Tone Board to sell!

This has always been true of AVRs, but is increasingly prevalent in stereo integrated amplifiers that do DSP Room correction (like your ELAC).

If your amp is doing Room Correction, then it’s doing so in the digital domain (which means running the analogue inputs through an ADC). Whenever possible, you should always feed such a device via its digital inputs (and avoid an unnecessary cycle of DA/AD conversions).

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The more you know…

I actually like this Elac amp a lot. I was using an old Sony AVR in its analogue direct setting. Even before realizing I was double processing I thought the Elac’s room correction and sub blending made the whole thing sound better than it did with the Sony.

And now. Wow. Much better still.