Software preamp and sound quality

Hi all! This may be a noob question but I’ve been concerned about how low I’ve needed to set gain in Equalizer APO to get reasonable volume control on my amp. Let me explain first by listing the chain : USB -> Denfrips Aries II (no volume control) -> Bottlehead Crack. I have gain set in APO at -10db just to allow me to turn the volume control on my crack a fraction of a turn. I’m concerned that by setting gain down lower that I may cause negative effect on sound quality. Is this concern valid? Should I consider ditching software and going with maybe a hardware solution? Any help is appreciated.

1 Like

I take it you are coming from a computer via USB into your DAC

I did find this thread on another forum. https://www.head-fi.org/threads/the-bitperfect-way-to-adjust-volume-using-equalizer-apo.949518/

It is a valid concern. Decreasing volume via software will reduce SNR. But is that a concern per se in your case? Likely not.

Looking at the specs, output from DAC is 2.2Vrms at RCA – more than the Modi 3. So your signal is probably coming too hot into the crack.

Note Pre-Gain in APO is equivalent to reducing the OS volume level.

PS: I don’t want to believe you’re using a cable like this one to feed the crack. That will probably clip the input stage of your amp. You’ll easily notice though.

Yes that’s right. USB from PC to DAC.

Thank you for the article! Very informative but frankly, more detail than what I can fully understand. Sounds like the outcome was not to change pre amplification in APO but rather to lower the volume in the player.

1 Like

I wish i knew this! I definitely would’ve avoided touching preamp settings. I’m running straight RCA from DAC to AMP. Thank you for the info.

You didn’t say how much boost you have for any frequencies. The idea of reducing the gain is so that any boost stays below net zero.

Meaning, if you have 10db boost somewhere you will need to have gain -10 so you don’t go above zero.

It’s ok to reduce gain even without eq.

I had a small 2.5db bass shelf but i think the headphones sound fine without it so will probably run without EQ going forward. Thx!