Upsampling/Oversampling

OP,

Upsampling refers to increasing the sample rate of an audio signal to make it higher resolution, typically to match the requirements of a specific system or to improve audio quality by adding more data points. For example, you might upsample 44.1kHz audio to 192kHz to get a smoother signal.

Oversampling refers to the process of sampling at a much higher rate than needed, often used in digital-to-analog (DAC) conversion or signal processing. It helps to reduce errors like noise or distortion and allows for more accurate signal reconstruction when converting between digital and analog formats. For example, oversampling might involve sampling an audio signal at 8 times the target rate (like 8x the base sample rate). This is what I do when I upsample FLAC files to 3X DSD

So, upsampling is more about matching a higher target sample rate, while oversampling is usually about improving the quality of signal processing by sampling more frequently than necessary.

You might want to pose this question on Audiophilestyle forum where they have very specific thread for Holo Audio May and way folks are maximizing their audio experience.

I also own the Holo May KTE DAC and most users who own this DAC prefer NOS. I'm streaming from an Aurender N200. Hardware based upsampling in my experience is pretty worthless. If you really want to play with extreme upsampling, stream from your computer and buy HQplayer and try the various modulators. I've played this game and did DSD 1024X, PCM 768 and so forth but in the end decided to get a dedicated streamer and use NOS. The upsampling to me was very fatiguing over the long term but it was fun to play with.

Redbook played with the transport set to 176.4 and with NOS is definitely superior to just 44.1, and I can live with that as is, or even just Redbook without the upsampling. The Holo is a very good dac, but if I happen to stumble onto an intriguing mod I am bound like everyone else here to follow it down its hole.

I think your problem has nothing to do with upsampling.

The biggest changes with modern DACs in my hearing has been with the way the digital filter behaves, specifically the high frequency roll off.

With older DAC's I often found a very large gap in performance between 44.1/16 and higher resolutions but that's narrowed a lot since 2000.  That gap has really narrowed most recently. 

Personally I upsample my Internet radio and streaming music to 96/24 and can't hear any improvements after that.

Just my thought. You are double oversampling? It might be overdriving the DAC when it starts to pop and click, it might be getting too hot? Think driving it like that for a long time will overheat it. The DAC is in overboots mode, receiving a very high signal to start, then it's trying to up convert that up-converted signal. The DAC chips will start heating up much more over normal use?

You can test, run the transport in normal mode, then upsample at the DAC, does it do the same thing? Reverse that with transport upsample, DAC normal. Does it pop?

Yeah, something like that is what I was suspecting although it is over sampling an upsampled file. No popping when NOS is in place on the dac whether the file coming from the transport is Redbook or the transport has 176.4 turned on.

The fact that the popping is length of time played dependent certainly points a finger at overheating.

Strange though that Holo recommends leaving OS and OS PCM etc.off period. Why then are these modes even available at all?

Thanks