Direct stream DAC “skipping”

For the past two weeks, everything working beautifully. Lumin U1 streaming Qobuz- DIrectstream-headphone amp. Today, inserted a Chord M Scaler between the Lumin and the Directstream, and started noticing occasional “skipping” or some sort of digital interruption in the stream. Troubleshooting has been unsuccessful. The M Scaler presumably is the source but don’t know why or how to fix. The M scaler when placed in my other system works fine. Ideas? Potential sources? The most weird symptom is that it frequently happens when I move from a sitting to standing position next to my system.

Any luck…?

I have no suggestions other than to suggest that you power down and check all connections. Then, power back up.

The M Scaler is an upsampler if I’m not mistaken. My guess I’d the DSD isn’t pleased with the data rate being presented. It’s superfluous because the DSD up samples all signals internally.

Like Watchdog mentioned, I bet the M Scaler is doing something to the stream that the DSD doesn’t like. I don’t have too many suggestions other than double checking connections and possibly trying different interconnects between the Lumin -> Scaler -> DSD.

I think I found the issue. My WiFi router was sitting on the floor next to my system. I put it up on a high shelf instead, where my body movements could not interfere, and problem solved. Lesson (for me at least) is that WiFi is hugely sensitive to otherwise trivial issues when part of a high end audio system. And, for those interested, I don’t know why but the Chord Mscaler does make a positive difference on DirectStream performance. Probably not worth buying one if you don’t already have it, but definitely a really nice addition. For details Google the Audio Bacon review of the Chord Mscaler used with DirectStream.

Thanks for keeping us posted. Crazy it can be that sensitive, but always glad for an easy fix!

There’s a technical paper that describes how the upscaling works, see:

The-theory-behind-M-Scaler-technology.pdf (

When I tried an M-Scaler it took a matter of seconds to hear how good it was at upscaling 16/44.1 (which is the vast majority of the music I have on my server).

Note also that you set the output data rate (which is related to the base frequency of 44.1 or 48) and in my case I upscale 44.1 to 88.2 or 48 to 96) - it always outputs at 24bit.

You can get equal to better results, and certainly more flexibility, from HQPlayer for a lot less money. Plus, the product gets regular updates.

I disagree. Read the science.

What do you mean!?

That doesn’t deserve an answer.

The science? You mean Rob’s descriptions of his product? That is not science. That is marketing. Or that PDF? I don’t see anything there (except the video delay feature) that HQPlayer does not do. In fact, HQPlayer does more!

What exactly do you think the M Scalar can do in the audio domain that HQPlayer cannot?

The answer is “Nothing.”

So you think all upscalers use the same algorithm to produce the same results?. I don’t.

That is exactly my point. HQPlayer offers more options for PCM and HQPlayer does DSD with a bunch of options too. With M Scalar, you don’t have any options and you only get PCM. Can you change filters with M Scaler? No. Can you change the dither/noise shaper? No. Can you do DSD? No.

I haven’t put an M Scaler in my setup but a friend did one in his to test. We listened to it and compared it to HQPlayer. We both liked HQPlayer more especially when upscaling PCM to DSD128. The flexibility of HQPlayer when playing PCM and DSD content was significant.

You are not comparing like with like. They are totally different products and will do totally different things on totally different hardware. I’ll not comment further.

I am certainly comparing like with like. HQPlayer and the M Scaler do the same thing. The M Scaler uses an FPGA while HQPlayer uses general purpose CPUs and GPUs.

What exactly do you think the M Scaler does that HQPlayer does not?