Fader Box for mixing setup

[craigmorris74]

Hello Craig, did you build the mini mixer you wanted?

Yes, built a box with four faders and some JLM audio Dingos for rebalancing/balancing.

 

[laitue5]

Thank you. Did you use 10k faders? I plan to build similar stuff but for stereo stems. More like a DJ mixer with That chips for debalancing/rebalancing.
Not decided which volume control yet. Maybe That 2181 VCA chip.
Is the global audio quality of your box good enough for your usage?

 

[craigmorris74]

Thank you. Did you use 10k faders? I plan to build similar stuff but for stereo stems. More like a DJ mixer with That chips for debalancing/rebalancing.
Not decided which volume control yet. Maybe That 2181 VCA chip.
Is the global audio quality of your box good enough for your usage?

Yes, went with 10k. They sound and perform great, transparent as far as I can tell.

 

[fragletrollet]

http://www.audiomaintenance.com/acatalog/faders_carbon.html

Cheers

Ian

What does VCA taper entail? Is it optimized towards controlling the gain of VCA's like the 2180?

I've been looking for a good source for quality stereo faders that don't break the bank; the p&g aml stocked in the past was about as much as a 24pos ELMA if I don't remember wrong, and only in 10k.

Where can I get stereo faders for my API mixer, which wants 1k (log)...?

Mouser has, surprisingly, good price on the fader assembly used in the Allen & Heath Xone42, which feels good, can take a beating and tracks good enough for all the world's hippest nightclubs. They're very deep though.

 

[sahib]

I have a stock of 10k Log and Lin stereo/mono. Here are some stereo versions.

I also have a small dual multi-purpose op-amp buffer card for make up gain.

Please PM if of interest.

 

[snakecained2]

What voltage are you giving the opamp? 15v?

 

[craigmorris74]

What voltage are you giving the opamp? 15v?

Sorry, just saw this. I ran mine off a +/-16V supply.

 

[Jano1954]

Hello Sahib!
Nice circuit.
Can you please state all the component values of this circuit?
Maybe publish a BOM ?
Thanks!

 

[sahib]

Hello Jano1954,

It is a text book generic design. The values depend on how you want to configure it. However, C7 and C8 are rail supply by-pass and 100nF is a standard value..

Both sides are identical. So, take the left hand side.

Say, to unbalance the input before the fader.

Keep R1, R7 and R3, R5 the same for unity gain. 10k.
C3, C5 27pF to 47pF. Or whatever in between.

C9, C11 are input coupling. Look up RC cut off frequency calculator on the net. 47uF will give you a lower cut off frequency of less than 1Hz. Footprint is 10mm in diameter. Plenty of space to put in anything you have in your parts box.

C1 is the output coupling. So, again you are driving into 10k fader and 47uF is plenty. R9 is normally there to keep the output at ground level and also to discharge the output cap when not in use. But as you have the fader you do not need to use it.

Now, there are hundreds and hundreds of circuit examples in the Technical forum that you can adapt this board to by lifting the values straight from them. Check for example, Amek, BSS, Soundcraft, anything really. It will be good for learning. In fact the component values I gave you up there will come up in most of them.