AliExpress SPDIF to AES converter

[tw99]

Amir did a review of a AliExpress USB to AES converter, which didn't perform well (although the test methodology was also questioned). This led me to have a look inside my AliExpress Coax SPDIF to AES device which seems to be from a similar heritage. Sadly they've removed the labelling on the two ICs, as had been done on the one Amir tested.

On the left hand side we have the coax input and a MicroUSB power input, AES out on the right.

I had a search for SPDIF receiver ICs, and couldn't find one that was 14 pins. Can anyone have an educated guess as to how this works ?

 

[Bamboszek]

SOIC-14 chip is probably just simple hex inverter or other generic logic chip used as logic level shifter.
SPDIF receiver is not needed, as apart from voltage levels and line impedance there are only slight differences between SPDIF and AES/EBU standards.

 

[voodooless]

The SOIC-8 is probably a simple line driver (opamp) driving the transformer.

 

[geoffrey5239]

The SOIC-8 is probably a simple line driver (opamp) driving the transformer.

In my Toslink to AES version the 8 pin chip is labelled as 09AD DS892. Mine has problems with the Toslink output from an LG TV which seems to be a known problem with LG TVs.

 

[Kal Rubinson]

my AliExpress Coax SPDIF to AES device

My AliExpress AES to Coax S/PDIF convertor device arrived DOA. I had no problem with a Canare or a Funk or a Weiss or a dumb adapter using pins 1+2. FWIW.

 

[phofman]

In my Toslink to AES version the 8 pin chip is labelled as 09AD DS892.

Differential Line Driver https://www.ti.com/lit/ds/symlink/ds8921.pdf ?

 

[solderdude]

Looks like what is used in the OP picture and drives the pulse trafo.

The circuit around the 14 pin dip is (very likely) the circuit below that drives the line driver (kind of reverse engineered it up to the line driver.
There is also a snubber across the pulse trafo input.

 

[tw99]

My AliExpress AES to Coax S/PDIF convertor device arrived DOA. I had no problem with a Canare or a Funk or a Weiss or a dumb adapter using pins 1+2. FWIW.

It's always a bit of a dice throw with AliExpress isn't it...

In my case I need the active adapter because my D&Ds don't seem to work reliably with the required passive cable (2.5M) from the SPDIF output from my MiniDSP SHD daisy chained through both speakers (+7M!). I'm right on the limit of what D&D say they tested, but it just doesn't work passively here.