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I'm not all in on digital systems because I'm not all in on DACs

We were lucky to have the makers of the @Arion1 speaker line join us in another conversation.  One of the points the rep made was he didn't understand what the problem was with digital among audiophiles. 

I am in many ways a digital music guy.  I have no vinyl and use Roon for all of my playback but this all stops when it leaves my Mytek DAC.  I've taken a great deal of care in selecting my integrated amplifier, and my speakers and how they are configured.  I rely heavily on OmniMic and Roon's DSP before the DAC... so why won't I just let go and go 100% digital?  Why don't I use digital crossovers after my preamp and convert my system to fully active?

The answer is in a series of experiences I've had with digital playback.  DAC's can sound wildly different.  I'm staring at two right now.  A Topping DX3 and a Mytek Brooklyn.  One sounds thin and lacking energy and bass while the other sound really good.

The same thing happened to me when I was trying to upgrade from my Theta Casanova.  I was looking for a processor that was HDMI friendly and inexpensive.  I went through a number of them which had the same problem:  Thin and gutless until I got an Oppo BluRay player which sounded better than all of them.  Sadly the Oppo DAC/headphone amp was a horrible ear drill to my ears.

So I'm not against digital signal processing or DACs, but within my budget I'm not willing to give up control over the sound of my DAC to a new crossover in the chain without listening.

What are your thoughts?

erik_squires
danager's avatar
danager
961 posts
 

Something like this maybe?

 

 

 

erik_squires OP
16,330 posts
 

From what I can see, Technics is using a PWM output with feed-forward built into the DSP engine.

Maybe there is feedback on the output as well, but I haven’t heard anything about that portion.

A real shame that after all that work it doesn't actually measure a lot better.

nonoise's avatar
nonoise
10,906 posts
 

That link helps a lot in understanding what Technics is using. In all of their descriptions, they (naturally) stop short of giving it all away. 

If I remember correctly, there is feedback on the output but it's only the negative feedback that's used after summing everything up. I'm probably wrong but I'm going by my memory. 

The retailer that I have it on order from said from what he can figure out, no one is doing it the way Technics is right now. There are a lot of ways of skinning the digital cat and some are similar, but not the same.

Here's one review of the SU-R100 that may shed more light. 

In fact, here's the passage about there being no DAC conversion being done: 

It’s also worth pointing out that there’s no DAC, no digital to analog conversion, taking place inside the SU-R1000. Incoming digital signals are upsampled (to 32-bit/768kHz), sent through a 1-bit Delta-Sigma converter, followed by another stage, the PWM converter, which forms a so-called “ternary” (2-bit) signal out of the 1.5MHz 1-bit signal. So each transistor only has to handle a switching speed of 768kHz/1-bit which is easier to handle in terms of the natural response time of a GaN-FET. I include this information knowing full well that few people will really understand it, yours truly included, so let’s just say that digital remains digital right up to the speaker binding posts.

Now I'm more confused but still eager to get the Technics.

All the best,
Nonoise

nonoise's avatar
nonoise
10,906 posts
 

The more I think about it, is it that the GaN-FETs are fast enough to handle the halved digital signal whereas a traditional MOSFET or JFET can't so with the latter, a DAC is necessary whereas with the GaN-FET, it's not?

All the best,
Nonoise

erik_squires OP
16,330 posts
 

It’s also worth pointing out that there’s no DAC, no digital to analog conversion, taking place inside the SU-R1000. Incoming digital signals are upsampled

 

Ok, now they are really splitting hairs.

1 - This applies only to incoming digital signals.

2 - The output stage IS a DAC.

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