JRock

Panning mixer inside MBFM

6 posts in this topic

I don't know about you, but I have 32 channels all filled up. Between the S900 and the MB6582, that's 16 channels right there. I love having the flexibility to process each one individually, but I don't have room for another mixer for every machine that I build :wink:

I housed my MBFM in a breadbox and there's plenty of space inside it and on the panel for this simple mixer I found at MFOS

It's a small circuit and it only takes up space on the faceplate of 8 knobs (and you could probably whittle that down to 4 if you just use the volume controls in the MBFM)

On the back of my machine I used 6 x 1/4" phono jacks and 4 of them need to be switching. 4 of them are individual outs and two of them are L and R for the stereo out. You can also run everything to a stereo TRS out for headphones as well.

I ran the MBFM outs to the tip side of the 4 jacks, then to the mixer inputs via the switch side, so If I want an individual out, all I have to do is plug a cable in and it breaks the connection for that channel (removing it from the stereo outs I have connected to the mixer circuit).

Since I didn't opt for a headphone out, I only need a TL082. If you use the headphone out too then you will need a TL084. You could probably use any Dual Supply Opamp in there. I'm sure there are better ones for audio for you audiophiles (although consider that every signal is already run through a TL074 on the MBFM anyway)

I can't get this file to upload. :rolleyes: I'll try again later. Here's the Link : MFOS USSPAM

Share this post


Link to post
Share on other sites

I used those designs to make the feedback mixer circuits and main mixer in my build too. Just one thing bothers me about your first schematic: the main outs are inverted from the inputs, though the headphones are correct. :)

Share this post


Link to post
Share on other sites

I was thinking, was it the link I wrote he means? Hehe, The main outs are inverted, it looks like. Not being the circuit designer, I would still claim that it is a compromise to make the circuit simpler. The IC is quad opamp? And the guy designed it this way to get away with only one chip. Maybe it would be smarter inverting the headphones instead then? Maybe free Eagle was used to route the board, and there was simply not space for more opamps :)...

 

When I design this stuff using eagle, I use a seperate PCB for the main outputs (4 opamps) and a seperate board for headphones amp. Then if I need more outputs I have them on seperate PCBs too (usually two outputs each board). Not a optimal solution, but when designing stuff for home-etching like I usually do, there's simply just no room for a lot of top layer routings and tiny traces :P. If mixer design is low channel count, like this, the inputs also goes on the main output pcb. ;).

Share this post


Link to post
Share on other sites

 

 

I wanted a panning mixer for my modular setup so i found that same design on MFOS and combined it with a Ken Stone circuit and ended up with this. I am building one now with a pcb from oshpark which i layed out in Kicad.

 

Maybe this will help.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now