Passive fader

[Coldsnow]

Hi
If I wanted to make a passive in line fader, would it work to go in to a
10k/10k input transformer to 10k audio fader to 600/600 transformer out.  Any problems with this solution?
Also any other parts needed.

 

[gurkan75]

You might lose low end with 2.5k (worst case fader position) driving a 600ohm transformer primary. I have seen 600ohm transformer-1k pot-600ohm transformer as a standalone attenuator but it is a costly solution with lowish input impedance.

Try the fader by itself if you have it, it will work fine into many inputs.

For passive stuff in a modern studio, shooting for 2.5k line impedance seems to work.

 

[abbey road d enfer]

Hi
If I wanted to make a passive in line fader, would it work to go in to a
10k/10k input transformer to 10k audio fader to 600/600 transformer out.  Any problems with this solution?
Also any other parts needed.

Won't work. The fader is not capable of driving the 600ohm primary. In addition, the 10 transformer secondary will see too much load.
Last, the fader law will not be correct.
Why all these transformers? Why 600 ohms output?

 

[Coldsnow]

I just had those transformers sitting around actually.  Also thinking it would be balanced in and out that way.  I wanted a fader long through type attenuation prior to a stand along summer. 

 

[abbey road d enfer]

I just had those transformers sitting around actually.  Also thinking it would be balanced in and out that way.  I wanted a fader long through type attenuation prior to a stand along summer.

It should work if you put the 600ohm xfmr before the fader and the 10k after.

 

[john12ax7]

Another thing to consider is that transformer distortion tends to go up with higher source impedance (the presence of the 10k fader).

 

[Coldsnow]

Actually, this may work better.  My summer has a unbalanced insert post gain which would probably work even better to insert a fader.  The output of the insert is 100 ohm and the input is 5k , plus 4 operating level.  Would just putting a 10k audio long throw taper work there better?

 

[Gold]

If you just want to use it for fades it will be okay because at the top of the throw the source impedance will look like zero ohms. It will go funky the further you fade but it might not matter.

If you want to use it to adjust levels like on a console it won’t work very well. At 50% attenuation the fader will look like a 5K source impedance which isn’t great.

A 600 ohm  or 1K fader would be much better. Assuming the 100ohm output can drive it.

 

[Coldsnow]

So it sounds like even if I get a 1k or 600 ohm fader attempting to use it like a mixing board fader, I will sacrifice sound to a degree correct?

 

[Gold]

So it sounds like even if I get a 1k or 600 ohm fader attempting to use it like a mixing board fader, I will sacrifice sound to a degree correct?

No that should work fine. The only caveat is whether the 100ohm output can drive a 600 ohm fader.  If it’s a 5532 it should be okay. If it’s a 072 not so much.

 

[abbey road d enfer]

So it sounds like even if I get a 1k or 600 ohm fader attempting to use it like a mixing board fader, I will sacrifice sound to a degree correct?

This is if you want to use transformers; transfrmers want to be driven with the lowest possible impedance. Now if you use your unbalanced insert, there is no problem using a 10k fader.