Passive summing mixers?

[Geoff_T]

Hi

I think your description of "passive" is a little off.

In my book passive means lacking any active electronic circuitry so a passive mixer is just a bunch of resistors creating a voltage summing mix.

In summing there are two approaches :- the voltage summing traditionally used by vintage Neve consoles and virtual earth used by later Neve and most other manufacturers.

Neither of these are passive as the consoles use input amplifiers and bus and output amplifiers.

A passive mixer is a box full off resistors

Posted from my iPhone

[StarfishMusic]

Originally Posted by Geoff_T

Hi

I think your description of "passive" is a little off.

In my book passive means lacking any active electronic circuitry so a passive mixer is just a bunch of resistors creating a voltage summing mix.

In summing there are two approaches :- the voltage summing traditionally used by vintage Neve consoles and virtual earth used by later Neve and most other manufacturers.

Neither of these are passive as the consoles use input amplifiers and bus and output amplifiers.

A passive mixer is a box full off resistors

Posted from my iPhone

Looks like I was wrong about the chandler after looking at the site again. It's the Shadow hills equinox I was thinking about mostly but I swear I remembered thinking the chandler was passive and the dangerous 2 bus was too. After looking at their site I think I may have been wrong. A passive mixer just doesnt seem like as much fun.

[Geoff_T]

Hi

If you have to plug it into power... It ain't passive

I believe the Dangerous unit with the switches is passive

Posted from my iPhone

[StarfishMusic]

Originally Posted by Geoff_T

Hi

If you have to plug it into power... It ain't passive

I believe the Dangerous unit with the switches is passive

Posted from my iPhone

The equinox has 2 mic pres for makeup gain and so does the smpro pm8. The only amplification is there right? I think the folcrom is the one that doesnt have any post amp. So then summing mixers make more sense to me. It was curious if they're trying to be console why they werent active like consoles are. Ive never used a passive mixer could be awesome I don't know. I'm a color fan though.

[Geoff_T]

Hi

Passive mixers are full of compromises. A bunch of resistors is ok but you need pairs of resistors if you want a balanced input.

Then imagine the fun of adding an input level pot and pan pot!

The input level pot has to be fairly low impedance to drive the pan pot and this reduces the input impedance. If you want balanced paths, you double up on all the pot sections.

So a transformer on the input will allow balanced input and a low impedance drive to the pots but adds greatly to the cost.

The monitor matrix panels on vintage Neve consoles, pre fitting the B338 buffer amps, was a nice example of a passive mix system, amplified by 1272 bus amps