• Registered: 2022-07-22
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Topic: ADI-2 FS Volume Pot Problem

Hi, RME!
I've recently became an owner of ADI-2FS, as a cheaper solution of ADI-2 Pro FS. I've also bought the Digiface USB to connect ADI-2FS to the laptop.
After connecting the headphones (Audio-Technica M50) I was disappointed that the level settings switch (+4/+13/+19) does not affect the volume pot. The headphone amplifier is very powerful and the slightest rotation of the volume pot already gives a lot of volume.
The problem is that at the beginning of the adjustment the pot adds volume in the right channel and then on the left channel alternately instead of simultaneously. So, to make the adjustment range more convenient, I have to attenuate the signal at the digital input reducing the output of Digiface USB in Totalmix, which is not acceptable in Hi-Fi.
On the other hand, the pot never turns off the volume completely, at the minimum, music is always heard in both channels on low level. But that's ok.
How can I fix the strange behavior of the cheap pot without asking DIYers?

2 Reply by KaiS (edited by KaiS 2022-07-22 12:41:19)

  • KaiS
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Re: ADI-2 FS Volume Pot Problem

You could use a passive attenuator of the type that is available for IEM’s.
This way you can use the upper range of the volume control.

Something like this:
https://ifi-audio.com/products/ear-buddy/

https://ifi-audio.com/wp-content/uploads/2018/05/EarBuddy-icon-cropped.jpg

KaiS's Website

  • Registered: 2022-07-22
  • Posts: 16

Re: ADI-2 FS Volume Pot Problem

Worth a try, thanks. Can this adapter with additional internal resistors change the sound of the headphones?

4 Reply by ramses (edited by ramses 2022-07-22 12:58:45)

  • ramses
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Re: ADI-2 FS Volume Pot Problem

We had this topic already in another thread, no issues to be expected.
In addition you can expect from Kai valid solutions.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

5 Reply by KaiS (edited by KaiS 2022-07-22 13:22:20)

  • KaiS
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Re: ADI-2 FS Volume Pot Problem

DAZZER wrote:

Worth a try, thanks. Can this adapter with additional internal resistors change the sound of the headphones?

These are relatively low impedance, tuned for low impedance IEM’s:

• Input Impedance: > 16 Ohm
• Output Impedance: < 2.7 Ohms

This way neither frequency response nor damping of your AT-50M is affected.

KaiS's Website

6 Reply by DAZZER (edited by DAZZER 2022-07-22 13:56:10)

  • Registered: 2022-07-22
  • Posts: 16

Re: ADI-2 FS Volume Pot Problem

Thank you very much!

ramses wrote:

We had this topic already in another thread, no issues to be expected.

Can you share the link please? I'm new to forum.

7 Reply by ramses (edited by ramses 2022-07-22 14:33:40)

  • ramses
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Re: ADI-2 FS Volume Pot Problem

DAZZER wrote:

Thank you very much!

ramses wrote:

We had this topic already in another thread, no issues to be expected.

Can you share the link please? I'm new to forum.

https://forum.rme-audio.de/viewtopic.ph … 07#p189007

Then follow the link to MC's statement ... https://forum.rme-audio.de/viewtopic.ph … 66#p182766

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

8 Reply by KaiS (edited by KaiS 2022-07-23 06:27:10)

  • KaiS
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Re: ADI-2 FS Volume Pot Problem

Those 2 discussions are a bit different, as they are about line level attenuators.

This case here is about headphones power attenuation.
Much lower impedance, not constant across the frequency range - albeit the AT-50M has minor variations only.

The basic idea is the same.

KaiS's Website

9 Reply by DAZZER (edited by DAZZER 2023-04-14 03:06:47)

  • Registered: 2022-07-22
  • Posts: 16

Re: ADI-2 FS Volume Pot Problem

Thanks for this good advice with cable adapter!
BTW MC, would it be easy to change that cheap pot to another one (10 k)? I have a small stepped attenuator implemented in a R-2R resistor ladder topology like this but much smaller.