High-end power amplifiers for audiophiles are made for use in combination with preamplifiers. Therefore, the volume is often omitted. When using a power amplifier without input volume as a standalone unit, it is necessary to add a volume unit to the outside or use an audio source that can always adjust the volume as in E30's Pre mode.
Yes,
@Toku but it seems this is exactly where the problem lies with E30.
When used in preamp mode and connected to a power amp (one without volume control), due to the way the AK dac chip works, there's an audible pop sound when sample rate changes and volume is adjusted and there's probably nothing that can be done about it. It's seems that all dacs using these chips exhibit this behavior.
This is kind of a deal breaker when you're considering using E30 in exactly this scenario and in my case I'm holding off buying it for now.
My use case would involve Raspberry PI -> E30 -> tube amp. The tube amp does have a potentiometer but for me there's still this unknown about the level of audiability of this pop sound. I guess the only way to answer this querstion is to try it out for myself.
Ignoring the pop-problem it really is looks like the dac I want to have - simple, small form factory, attractively priced, good connectivity etc.
This issue is being somewhat overlooked here and the recommended remedy is to get a preamp in between E30 and a power amp in order to attenuate the pop sound, but the problem with this setup is that you need to buy more gear (preamp). I hope you can see, how the simple solution is not that simple anymore.
