Digital Drive

0.1 Ohm: isolated USB DAC

98.217.204.116

dave789

On a DAC with isolated USB input using Analog Devices 4160 chip, I measured the resistance between
#4 pin of the USB input socket and
the � of the RCA analogue line level signal output socket.
It is 0.1 Ohm.
(By the way, I posted about the stain of this DAC below.)
Is this usual on a DAC with isolated USB input?

P.S.: I measured again and got 0.0 Ohm.

Edits: 11/25/14

Follow Ups:

by design - dave789 11:24:51 11/27/14 (0)
The manufacturer says it is so by design on that model. They said they had done plenty of tests about the relationship between circuit grounds and the aluminum chassis.

Edits: 11/27/14
FUNCTIONAL BLOCK DIAGRAM FOR ADUM4160 - dave789 06:36:51 11/26/14 (0)
There are GND_1 and GND_2.
I guess separating them is a purpose of using such an isolation chip.
The resistance between the ground of the coaxial digital input socket and the ground of the analogue output socket was 7.2 M Ohms on Peachtree Dacitx. I think this is what we usually mean by "isolated" grounds, "isolated" digital input, etc.

Edits: 11/26/14 11/26/14 11/26/14
RE: 0.1 Ohm: isolated USB DAC - Awe-d-o-file 05:43:42 11/26/14 (0)
0.1 and 0.0 are in effect the same measurement. I can't speak to whether there should be continuity between the RCA - and any part of the USB connector.

ET
RE: 0.1 Ohm: isolated USB DAC - fmak 09:27:41 11/25/14 (0)
I am surprised that you still have it. Since it is Korean and if you bought it from there (even on eBay.com) good luck.

I will never do so again, having been cheated out of my money on a dead Samsung Ram
RE: 0.1 Ohm: isolated USB DAC - Thorsten 06:28:08 11/25/14 (0)
Hi,

The reading should be infinity if the USB input is isolated. So in your case even though a USB Isolator is (supposedly) present there is no isolation.

It could be a fundamental design flaw (low cost PRC made gear is full of these) or it could be a sample fault due to bad soldering etc. (which are also not uncommon in low cost PRC made gear).

I would have the unit inspected and analysed by a competent technician to see what is going on and in the meantime file a claim with E-Bay/Credit Card Company and see how it plays out.

Or just pack this piece up and return for a refund if you can.

Ciao T

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to untolerable pain. Really, what more could we need?

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