DAC's : The missing feature: Signal quality


One thing I wish DAC's would provide is some idea of how much jitter and noise a particular input provides. This is something which I think with a little work could be gleaned from the input circuits.

I want something that tells me "woah, that's a really dirty signal coming in, but i"ll do the best I can with it."

One common source of noise is ground loops. Another may be high jitter from a source like Apple TV. This would also help us evaluate the benefits (if any) of various signal cleaners and reclockers.

Best,
E
erik_squires

There is no way this was a jitter detector.  This was a classic S/PDIF receiver error detector.  Even my DAC has this.

Most logic families used in DACs are too slow to make these type of determinations.  We are talking about gates with propagation delays of 1nsec trying to detect a jitter of 10psec.  Not going to happen.

Steve N.

Empirical Audio

Hey Steve! I saw your purifier on your web site. One thing that caught my eye was incompatability with XMOS based inputs. Is this because they require a +5 V input?

erik - Purifier??  I don't know what product this is.  Do you mean the Short-Block?

There is no incompatibility with XMOS-based USB interfaces.  Sometimes they need +5V from the USB cable depending on the design.  The SB cuts this voltage.  It doesn't matter because it out of production now.

I would highly recommend this product for USB:

https://sotm-usa.com/collections/sotm-ultra/products/copy-of-tx-usbultra-regenerator-1

This is the ONLY thing I have tried that makes my USB almost as good as my Ethernet interfaces.

Steve N.

Empirical Audio

audioengr3,129 posts11-24-2018 3:20pm

Steve, nice list in this post. With respect to the EA SM reclocker, I can see where your PS upgrade fits on the list. Where does the OTL upgrade fit, under jitter?

The OTL upgrade simply removes the output isolation transformer. If the DAC has a transformer on the input, there is no reason to have two in series. The pulse transformer is really not necessary, but helps with ground-loop noise in some systems where the DAC does not have an input transformer. Both the standard and OTL versions of SM reclocker have very low jitter, but the OTL is slightly lower. If you want the lowest jitter, then OTL is recommended. Plugging the AC power for the DAC and the SM into the same outlet usually minimizes ground-loop noise, so the OTL works fine.

Steve N.

Empirical Audio