Audient ID14 opamps MOD issue

[Tubetec]

Sounds like some of the shortcommings of a single USB 5V rail are becoming apparent here , same with the SSL2 .

 

[maosante]

Hey guys,

I've just fixed this issue. With the information mentioned here about current consumption of the opamps I did a little research on current consumption of my current mod, then, after calculating which opamps combination would maintain the stock current consumption, I bought new opamps that can fit the board and replace the OPA1656 which are very current "hungry".

The OPA1692, have very low current consumption and can leave extra current available for the OPA1612 which are the best sounding opamps I have tried so far (from my point of view).

The result is no noise at the input #2 and a better sounding interface for a budget (yet, I don't recommend this mod to anyone).

Turns out opamps give you a color, which can not be qualified just by their specs, some colors are desired for some uses. Sometimes people like distortion because it sounds brighter and louder. Depends what you are looking for. Some users said here, "why did you mod this interface if it just sounds great", this is definitely a perception, which I didn't agree and found myself modding the interface.

Thanks for all the information you guys leaved at this thread, it offered enough knowledge to fix the issue. Yet I know there are many other aspects to be aware of when replacing an opamp, current is just an important one but not the only one.

Kind regards.

 

[Newmarket]

There are some fairly basic things you can test to look for the cause of "colouration" of the signal if you want to investigate. I'd start with quantifying harmonic distortion characteristics using FFT spectrum analysis and also investigating intermodulation distortion. And, in a converter product, anything related to clock / sampling frequencies.

 

[maosante]

I've done some simple harmonic distortion analysis with this 1khz sine wave test tone and my DAW. I did it by connecting the output to the input at its max volume, I don't know if this is the correct way of doing the test, but here are the results.

OUTPUT #1 OPA 1612

INPUT #1 OPA 1612

INPUT #2 OPA 1692



OUTPUT #3 OPA 1692

INPUT #1 OPA 1612

INPUT #2 OPA 1692

 

[Khron]

What were the input meters showing?

I don't know if this is the correct way of doing the test

Depends entirely on what "this test" was supposed to show / demonstrate.

 

[maosante]

I think my interface needs a rescue maintenance . But in my country there's no technical support for this. Revive audio offer this mods, but I don't know if it is still possible with the things I have done to the board. Do you know any other company that can work with this?

 

[fixorfling]

Pins 5,6,7,8 look dry,
compared to the left side.

 

[SergioGarcia]

Wow, the measurements of 1612 on the input show really bad behaviour. An opa 1612 should not act like this, here there is something wrong with it.

 

[radardoug]

It looks like you are clipping. That is not a valid test.

 

[maosante]

Pins 5,6,7,8 look dry,
compared to the left side.
View attachment 121038

This picture is the unmoded interface. Which means is the actual stock opamp. Maybe there are traces that can't be seen in the picture though.

 

[maosante]

Wow, the measurements of 1612 on the input show really bad behaviour. An opa 1612 should not act like this, here there is something wrong with it.

Yeah, there's something wrong, by now I'm using the interface in a regular basis without the inputs. I think it might need a revision to figure the problem out. If there's a fix I think I will leave the revision to an expert, since I have tried several things with no success and might blow up what's working now. Fortunatelly, the Audient has an optical input, which I can use with external gear for recording or tracking.

 

[Khron]

Just couldn't leave good enough alone...

 

[maosante]

Yesterday I resume this project and found out what might be causing the issue. Somehow when soldering the new opamp c176 was accidentally soldered and heated to a non returning point.

Any ideas how to figure out the value? Since this configuration is not the same as input 1-2 I don’t really know if looking other cap values at the other opamps would be correct. Thanks in advance.

 

[Khron]

Is that connected between pin 4 and ground?

If yes, good bet it's a 100nF / 25v or so, negative supply bypass.

 

[maosante]

Is that connected between pin 4 and ground?

If yes, good bet it's a 100nF / 25v or so, negative supply bypass.

yes to pin 4. Got to check if it does go to ground.

 

[maosante]

just checked and the right lead is connected to Pin 4 and 5.

 

[maosante]

just checked and the right lead is connected to Pin 4 and 5.

If yes, good bet it's a 100nF / 25v or so, negative supply bypass.

So, it is a dual opamp, then which other value of capacitance should be there? Any ideas? Thanks in advance.
Would a 104 ceramic cap do the trick? It seems to be rated at 50v

 

[Khron]

What's a "140 ceramic cap"?

 

[maosante]

What's a "140 ceramic cap"?

104*

 

[Khron]

If you really can't find / don't want to find 0603 X7R 100nF/25v caps, sure, I guess a through-hole one is better than none at all.