Why are digital streaming equipment manufacturers refusing to answer me?

@mihalis I simply shared what I experienced, with that MSB DAC and that same module. Which MSB DAC did you own? I don’t see it under the System for your current gear. So for the ProISL / ProUSB module combo, was it the same you had? That’s what I had.

My subsequent attempt in technicality of the benefits of USB protocol in streaming (or lack thereof) was simply based on my limited technical knowledge. I don’t pretend to be fully able to explain everything I hear.

As for the MSB ProISL / ProISL implementation, yes, the main objective is to eliminate copper, therefore the electrical interference associated with it, by introducing fiber. But it’s not as simple as that. The first device, what they call ProUSB (the dongle that stays outside the DAC, on it’s own) converts USB to their proprietary ISL audio transmission via the fiber. Then the module that goes into the DAC, what they call the ProISL module, is the one that is directly connected to the DAC architecture. Basically copper USB cable to the ProUSB dongle input, then fiber optics cable from the ProUSB dongle output, to the ProISL module (attached to the DAC) input.

So it’s not as simple as fiber, and here you go, all problems solved magically. The conversion itself is perhaps just as important, as in theory can introduce other issues.

Further, many of the non-believers will tell you that any of that is not an issue at all, and any competent Topping China $50 DAC has all that built in, galvanical isolation and all, so totally unnecessary to go through fiber they will tell you. So here is that.

The test you did Mihalis sounds well thought out and the results exactly as expected.

It is possible for the incoming data stream to impact clock timing but that would be expected in a poorly constructed $50 USB DAC from China not an MSB, not to mention the pro-ISL fiber does not communicate USB.


There is also no guarantee that thyname's high end streamer does not manipulate the bit stream or that what he compared it against manipulated the bit stream and the one he prefers does not. We like magic and so we hold on to the magical explanation when the more likely one is almost always right.


Keep in mind a lot of high end components are intentionally euphonic and their euphonic signature dominates their sound not necessarily their technical competence.

Thyname it’s the select dac with the same interface you describe. Since I am receiving bit perfect signals nothing happening prior to the conversion to fiber matters IMO. If the signal was not bit perfect (msb offers an extensive test) then it could have affected things. 

Audio2design, I couldn’t agree more.

Getting “bit perfect” signal is not a rocket science. You make it sound like people are all naive and streaming music from some noisy desktop computers. It’s extremely easy with all major streaming protocols, including from Roon via a NUC, Nucleus, Innuos, and so forth.

MSB Select DAC starts at $85,000 I believe. Once you add your ProISL / ProUSB module (that alone is $2,000) and perhaps the second power base, and the upgrade clock, then the price becomes ridiculous.