Audient ID14 opamps MOD issue

[maosante]

Hey guys,

I've recently upgraded the opamps of my interface Audient ID14 MKII for better bandwidth, noise, transient response, etc. I like how it sounds at the headphone outputs, yet, the inputs, have gone wrong and 1/2 outputs also have a problem. Here's what I swapped:

Inputs
Guitar input 1 OPA1678 → OPA1612
Input 1 OPA1678 → OPA1612 (120hz hum)
Input 2 OPA1678 → OPA1656 (noise a crackle up to -42db - sometimes it works well)

Headphone outputs
TL702 → OPA1612 (Crystal clear)
OPA1678 → OPA1656 (Crystal clear)

Balanced outputs
1/2 OPA1678 → OPA1612 (bass is kind of missing, mixes gets messed up at the low frecuency)
3/4 OPA1678 → OPA1656 (Crystal clear)

I would really appreciate if you can give me a light on this one!
There's a picture of the circuit with the new OPA1656 at the input #2 (if is useful by any means)

Thanks for your help.

 

[Khron]

The first and most obvious question is... Why???

But moving past that, you may or may not have noticed that your newly chosen opamps (OPA1612 and OPA1656) both have rougly double the current consumption per channel , than the stock OPA1678's (or 3-4x compared to the TL072).

Especially since the iD14 is such a small (and relatively cheap) unit, do you really think Audient would've overbuilt the power supply section THAT severely, to handle 2-3x the load? Why would they have? That's just extra money down the drain...

That being said, we can't know where your desoldering & soldering skills lie, whether you may or may not have over-"cooked" something, or damaged some traces, or whether (worst case) you might've ESD-zapped something (unlikely, but not impossible).

 

[Newmarket]

"OPA1656 → OPA1656 (Crystal clear)" ???

 

[maosante]

The first and most obvious question is... Why???

But moving past that, you may or may not have noticed that your newly chosen opamps (OPA1612 and OPA1656) both have rougly double the current consumption per channel , than the stock OPA1678's (or 3-4x compared to the TL072).

Especially since the iD14 is such a small (and relatively cheap) unit, do you really think Audient would've overbuilt the power supply section THAT severely, to handle 2-3x the load? Why would they have? That's just extra money down the drain...

That being said, we can't know where your desoldering & soldering skills lie, whether you may or may not have over-"cooked" something, or damaged some traces, or whether (worst case) you might've ESD-zapped something (unlikely, but not impossible).

Why? Well I wanted to have much more clarity in my mixes, which indeed happened with the OPA1656 at the outputs. As you mentioned its a relatively cheap interface, I just did it to get an upgrade on a budget.

As you mentioned it seems that the power drain of all the opamps lefts the input #2 with no power, this lack of power might be the noise generator. Is there any solution you would recommend?

My soldering skills aren't the best, but the interface still works, which means I haven't fried something yet.

 

[maosante]

"OPA1656 → OPA1656 (Crystal clear)" ???

Sorry, edited!

 

[Khron]

Well, at least in order to minimize confirmation bias, you could have considered modding one input / output at a time, to be able to make direct comparisons.

How does one measure, or at least quantify, "clarity"?

 

[maosante]

Yes, I did that before, the amount of noise was nearly the same. -120db no gain. Yet it has a bump in the highs at maximun gain, I've read that the OPA1656 is more sensitive to noise generated by the resistors. And in fact, with the OPA1678 at input 2 it would get high noise levels as described before, changing Guitar and input 1 for OPA1656, results in noise at input 2. I did change the input 2 to OPA1656 with the hope to get the right response with no success.

 

[Khron]

"Closed"? "Opened"?

 

[maosante]

"Closed"? "Opened"?

Knob closed, no gain. Opened, full gain at the interface.

 

[jeremynothman]

and there I was thinking that my ID4 MKII sounded bloody amazing for the money!

 

[Khron]

and there I was thinking that my ID4 MKII sounded bloody amazing for the money!

Yours probably still works, and has no extraneous noises... I'm assuming...

 

[Newmarket]

Have to say that this thread highlights the perils of "Op Amp Rolling" without considering the whole circuit (and of course the PSU).
Heat from resistors - how much power is this small signal interface burning off

 

[TwentyTrees]

and there I was thinking that my ID4 MKII sounded bloody amazing for the money!

Ditto, I always liked the sound.

 

[Newmarket]

Wrt modding this or anything. It seems fairly basic that you should account for any increase in power consumption before implementing any changes.
Sorry to be critical but thid is just basic stuff.
And in fact also consider if a reduction in current demand might be an issue wrt SMPSU PSUs wrt "hiccups" etc...

 

[maosante]

Have to say that this thread highlights the perils of "Op Amp Rolling" without considering the whole circuit (and of course the PSU).
Heat from resistors - how much power is this small signal interface burning off

Correct me if I'm wrong, when doing a circuit for amplification there are factors that contributes to the noise levels. Resistors can contribute to noise.

Here's an OPA1656 chart below. Other opamps are not sensitive to resistors noise, so they reject it in a more effective way. So if circuit was made for another opamp clearly it won't fit perfectly, as you mention, that's clear at this point. Would you have any advice on how the PSU can be modified.




Im sure I've risked the whole integrity of the circuit in order to achieve "a better audio". But isn't this space and forum about it? Is there something you would recommend to mod the PSU. Here's a high resolution picture of the Audient ID14 first layer.



From what all you guys are saying going back to the original Opamps is your solution right?

 

[Newmarket]

Yes. I understand all this quite well (it's kind of part of my trade,). Even theoretically perfect Resistors have a noise contribution dependent on resistance and temperature (See Boltzmann) and they further contribute to any noise generated by means of current noise.
It's not a case of resistor noise being rejected. Rather the (ein X R) noise contribution is simply less when current noise is of a lower magnitude.
Wrt PSU then you just need something that fits the bill - ie maintains the voltage rails at correct levels and with low enough noise. If you want to check this then you'll need to look at the voltage rails with an oscilloscope.
And tbh it's probably worth reinstating the original opamps yo confirm that nothing has been damaged.

 

[molke]

From what I can remember (I don’t use the ID14 anymore), everything in this interface is designed to run on USB bus power. Only phantom power needs the external PSU. So I’m guessing the default PSU capabilities are pretty much exhausted.

 

[maosante]

This is the Audient ID14 MKII which has no external power supply. As you mention is USB-C powered.

From what I can remember (I don’t use the ID14 anymore), everything in this interface is designed to run on USB bus power. Only phantom power needs the external PSU. So I’m guessing the default PSU capabilities are pretty much exhausted.

 

[molke]

This is the Audient ID14 MKII which has not external power supply. As you mention is USB-C powered.

Sorry, somehow I missed that. Nonetheless, 0.9 A (or 1.5 A: “Provides higher headphone outputs levels”) at 5 V, allowing for some losses, doesn’t leave much room for op amp changes with the amount of circuitry crammed into these devices.

 

[maosante]

Sorry, somehow I missed that. Nonetheless, 0.9 A (or 1.5 A: “Provides higher headphone outputs levels”) at 5 V, allowing for some losses, doesn’t leave much room for op amp changes with the amount of circuitry crammed into these devices.

That's right, I have swaped the guitar input (IC1) with the TL702c, because I don't use it and the input 2 (IC6) had no noise when using low levels, input 1 (IC3) is ok, until I cranked up the volume, input 2 malfunctions again.

This means is a thing of power as you have mention here, not compatibility, I'm thinking if putting other TL702c at the 3/4 outputs (IC8) (look at the picture) would help the input 2 (IC6) to work correctly.



By the way, I love the OPA1612 sound, it really marks a difference in clarity and depth.