Strange issue with Apogee AD-16 interface

[Whoops]

Can you tell if an op-amp is fried without removing it?

Sometimes it's possible to test opamps in circuit if you measure shorts between Pins that shouldn't be shorted.
Other times the only option to be sure is to remove them and replace for a new one, then you know if the problem was in the opamp or not

Then again, you need someone with experience to work on that, I remember the board being packed and full of very small components. Not an easy job.

Yes it's very difficult and both the AD8000 and AD16 are all SMD, difficult to repair and without a schematic very difficult to troubleshoot.

some more info here:

https://groupdiy.com/threads/apogee-ad8000-da-converter-chip.50196/

 

[orpheusmaximo]

I know what you mean. "Forced obsolescence" is terrible. I think you either live with the limitations, or try something. Can you tell if an op-amp is fried without removing it? Then again, you need someone with experience to work on that, I remember the board being packed and full of very small components. Not an easy job.

P.S: The headphone jack on my AD8000 "lost" its left channel long ago. But I love that unit so much, I'm running it for as long as I can, maybe even getting a 2nd one ( but it must come with the ADAT card, and at a very reasonable price or it won't be worth it ).

 

[orpheusmaximo]

Sometimes it's possible to test opamps in circuit if you measure shorts between Pins that shouldn't be shorted.
Other times the only option to be sure is to remove them and replace for a new one, then you know if the problem was in the opamp or not



Yes it's very difficult and both the AD8000 and AD16 are all SMD, difficult to repair and without a schematic very difficult to troubleshoot.

some more info here:

https://groupdiy.com/threads/apogee-ad8000-da-converter-chip.50196/

And a sad story it is, he bought five chips for the DAC card ( which I have and don't use btw ) but the
unit gave it up on the power supply and he sold it for parts.

 

[Khron]

And a sad story it is, he bought five chips for the DAC card ( which I have and don't use btw ) but the
unit gave it up on the power supply and he sold it for parts.

Really? The power supply is quite likely the least complex side in a unit like that

 

[Whoops]

P.S: The headphone jack on my AD8000 "lost" its left channel long ago. But I love that unit so much, I'm running it for as long as I can, maybe even getting a 2nd one

That's the thing this units sound great,
I think I still even prefer the sound of the AD8000 than the Rosetta that came after, but this is a feeling as a sound engineer and I haven't done a more "scientific" comparison.

Adat card out is a must on an AD8000 for me also, so I understand it completely.

Unfortunately all the AD8000 that I know that are still being used by friends and colleagues all exhibit some fails even though usable.

I advice to contact Apogee, maybe they still service this units, and maybe they still have the "free repair fee" policy

 

[scott2000]

I advice to contact Apogee, maybe they still service this units, and maybe they still have the "free repair fee" policy

When I was in touch with them regarding a Rosetta200 this was one correspondence after going back and forth troubleshooting and drawing out some of the circuit.... I think the thread where I reached out here to the forum is below in the "Similar threads."... Maybe it would be useful to post some of the correspondence somewhere because Heikki is the only one who ever saw all of them iirc...but maybe they are in the thread already... Can look later.
At least with the Rosetta200, looking at the chips , then looking at application notes, it was not terribly difficult to see what what going on. Even if it didn't make sense to me.

"Usually we have a very high pre-paid repair fee on these units, $599, due to extremely limited parts and the high amount of labor that usually happens, as you are finding!

But she said we can set up a pre-paid $75 diagnostic fee, and we will contact you if the repair is over $195. She is hoping we can get this all fixed here for that low a cost, given the specifics........."

 

[skipwave]

Just looking at the manual real quick there's a mention of the wc ratio setting? Figured may as well be mentioned...
Fascinating....is it necessary to clock the da?

Yeah, I should be able to set WC ratio to 1x as the default setting, just haven’t found time to do that rain dance.

Clocking the DA is necessary, as the AD is providing the house clock rather than internal. I could let the RME pass the clock data through on the TOSLINK cables, but I hear a small, but noticeable improvement with clock data via WC instead. Also, that was a very noticeable improvement when I upgraded my coax WC cable from crappy no brand cable to Gotham Audio cable. I was shocked how dramatic the difference was.

I will forever be haunted by 96.01kHz. On my death bed I will be muttering, “ninety-six oh one…. Oh one… oh one” and everyone will think I’m reminiscing about my youth.

 

[Whoops]

I will forever be haunted by 96.01kHz. On my death bed I will be muttering, “ninety-six oh one…. Oh one… oh one” and everyone will think I’m reminiscing about my youth.

I totally understand that feeling, I would not rest until that 1 completely disappeared,
I would get totally obsessed about it.

 

[JohnRoberts]

Repairing gear without schematics has always been part of the challenge (sport).

Admittedly modern gear with perhaps obscure or obscured (pn scraped off) ICs makes it harder to sort out. Often IC application notes will provide helpful information.

[edit- IIRC gearslutz had a cross reference of what convertor chip sets were used in branded convertors /edit]
JR