Mixing multiple MHBP_SID outputs recommendations?

[alchemist]

Hello,

 

How do you mix the outputs of the SID modules, if you have more than 1 pair (e.g. 4 pairs)?

- mix table ?

- static passive mix (using resistors) ?

- active mix (using IC's) ?

 

[jrp]

All can be done, it depends on your needs.

 

My sid has independant outs with stereo volume controll on each voice. Voices 2 to 4 have a little switch that mixes them with voice 1.

I used a simple inverting opamp mixer as can be found using google.

[alchemist]

Thank you. I will first try with a passive resistors matrix, and later an active system with individual volumes.

[Altitude]

I use a 4 channel stereo mixer (MAM SLE82) works like a dream.  I'm sure that there a DIY ways but that with a 4xTRS to 8xTS snake worked out well for me and cost less than $100

Edited May 14, 2014 by Altitude

[alchemist]

I already have a Behringer RX1602, but it is full.

I can also use a small mixer, but I would like to integrate the sound mixing into the C64 box.

[jrp]

same for me. integrating mixing is very convenient. Although i have a 40ch mixing desk for all sorts of tricks, it´s sometimes nice and handy to be able to have all sids mixed into a single out from the cs.

[alchemist]

Thanks for your ideas !

 

I think I will try to provide 8 individual  + 2 mixed outputs. I have found one or two Op Amps from the time I was reading Elex (25 years ago). This could sound quite... vintage ;)

[jrp]

You could also consider to use the first two outs for mixing. Channel 2-4 would then need a dual switch to connect to the mixed output. This way you can easily change between using individual outs or a mixed output without replugging any cables.

 

Try these old opamps if you like the sound it´s fine. YOu should check with a scope if these start to oscillate when driving cables. As for me, i would rather use those in a distortion effect of some kind rather than using them for main outs of any device.

You want something that is capable of driving any real world load easily. 5532 is a good choice as it´s cheap, low noise, stable under usual conditions and can drive 600r loads. So your sound will be uninfluenced by cable length and the load it sees.

Of course TL072 is an option often seen, but it is much weaker so the outputs are more prone to picking up noise and hum compared to the lower output-impedance chips like the 5532.

Edited May 16, 2014 by jrp