Matrix Mixer

Talk about music gear for noise music

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timdrage
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Re: Matrix Mixer

Post by timdrage » Wed Apr 18, 2018 6:52 am

Yeah seems fun! I can't get half my components to turn up in the 3D viewier but that's probably said Library stuff i don't understand yet :D

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Fletcher
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Re: Matrix Mixer

Post by Fletcher » Fri May 04, 2018 3:29 am

Ive been looking for a 4x4 matrix mixer for some time, the xiwi kits always seem to be sold out (look ideal for me, starting out with kit building)

Also seen this:-
https://www.musicstore.de/en_GB/GBP/Doe ... 6lEALw_wcB

which is obviously a modular card, but as I am a fabricator it wouldn't be a problem for me to make a housing for it. It doesnt say, but I am presuming this is passive? Has anybody got any experience of these?

(PS I know I said 2 days ago im on a gear buying blackout but I am planning ahead :lol: )
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Misomusist
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Re: Matrix Mixer

Post by Misomusist » Fri May 04, 2018 5:05 am

Fletcher wrote:
Fri May 04, 2018 3:29 am
which is obviously a modular card, but as I am a fabricator it wouldn't be a problem for me to make a housing for it. It doesnt say, but I am presuming this is passive? Has anybody got any experience of these?
Given it has switchable polarity on the outputs, and you can see chips on it. I don't think it's passive.
I think trying to quantify music is one of the biggest wastes of time in the world, like discussing your favourite colour or deity or pizza topping. People should realise that and get on with their life.

Image

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Fletcher
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Re: Matrix Mixer

Post by Fletcher » Fri May 04, 2018 5:38 am

Ah well spotted, didn't realise there were multiple photos.
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An electronic music zine in occasional print format

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Fri May 04, 2018 8:27 am

Image
https://www.cgs.synth.net/modules/uni33 ... mixer.html
this was open in one of my browser tabs

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crochambeau
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Re: Matrix Mixer

Post by crochambeau » Fri May 04, 2018 8:45 am

I said it once, I'll say it again - bipolar function is HUGE with regard to employing these as we are wont to do. Center off is not difficult to wrap your mind around at all.

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Fri May 04, 2018 9:29 am

bipolar function with double ganged 3 way toggle switches?
never implemented that function before
in any designs

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crochambeau
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Re: Matrix Mixer

Post by crochambeau » Fri May 04, 2018 10:11 am

I read back to my posts in December and it doesn't look like I mentioned it (it actually took me a bit of head scratching and then plugging it into my scope to discover, so it's possible I hadn't realized it yet) but the Matrise mixer I have functionally follows the CGS schematic you linked, at least to some degree - in which the linear potentiometer sweep goes from inverted full at CCW to channel null at center of sweep to non-inverted full at full clockwise rotation. No additional switches involved, just a standard/bipolar mode per column.

This results in being able to stagger each node independently in the matrix mixer, instead of selecting polarity by column (the way the current Pladask offering and manual reflect). So yeah, if you're building an active one for yourself I'd recommend the linked CGS approach personally...

...though I understand the reason Pladask shifted to a total column polarity/volume pots go from null to full only was due to confusion from the end users.

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Fri May 04, 2018 11:29 am

pardon my dumb question on this subject
yet need asking anyways
if making matrix mixer for cv & audio input
do I get a DC offset positive-only voltage
does it not pass any CV in negative polarity
since the then voltage is going straight to ground
would it be better inverting the input using another opamp
with path toggle switch
never experimented with polarity in such ways before
probably stupid question anyways
since this seems like audio path only matrix if polarity is impeimented
not enough coffee yet
sort of wanting the EMS matrix effect
just realized can do that with big bag of 2 position toggles
instead of pins

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Fri May 04, 2018 11:41 am

Image
always reminds me of playing "Battleship"
anyways typing out load
4x4 matrix is good enough project
EMS VCS Synthi matrix is another beast all it's own

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crochambeau
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Re: Matrix Mixer

Post by crochambeau » Fri May 04, 2018 12:24 pm

WhiteWarlock wrote:
Fri May 04, 2018 11:29 am
if making matrix mixer for cv & audio input
do I get a DC offset positive-only voltage
does it not pass any CV in negative polarity
since the then voltage is going straight to ground
What constitutes "ground" is going to hinge on how the opamp is powered and implemented.

Are you working with a single rail supply or a bipolar supply? I would recommend a bipolar if you want to share CV and signal on a DC coupled system.

If you begin with a single rail, positive voltage and ground, building a virtual ground at half rail is beneficial to audio, but since this isn't AC coupled all your output (including the CV) starts at half rail which is probably an issue (unless you're embedded inside a greater circuit).

With bipolar, you can balance/center the opamp so the signal path sits at a voltage potential that amounts to ground. This insures most positive and negative swing from the signal standpoint, but will allow CV to reach into negative if fed into an inverting stage. If negative DC is an issue you'll have to address/restrict that either on output or input of a following stage.

There are opamps that are designed to operate down to the negative rail (for use in single rail supplies) but there are trade offs, and I am not sure it'll be easy to get away with running audio on a DC coupled circuit using one.

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Fri May 04, 2018 12:41 pm

hear ya...
have experimented before with half rail "fake ground" midpoint V designs
yet for this design it's not being powered from +9v/ground or +18/ground
so thus utilizing full +/-
no where near starting on that vero
merely asking some dumb questions at glance
while doing multiple other things
spring cleaning time
thanks for the input
btw it's refreshing having someone for feedback
that even comprehends the dumb questions

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Misomusist
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Re: Matrix Mixer

Post by Misomusist » Sat May 05, 2018 5:45 am

Fletcher wrote:
Fri May 04, 2018 3:29 am
but as I am a fabricator it wouldn't be a problem for me to make a housing for it. It doesnt say, but I am presuming this is passive?
Honestly, if you are good at fabrication, making your own shouldn't be that hard, the bulk of the work is in drilling holes for the pots and jacks and making all that stuff line up. I'm thinking you, if you have the pots angled, you could maybe just run solid copper thru the tags, and put a little dab of solder on each, kind of like the diagram shows with straight lines.

Image
I think trying to quantify music is one of the biggest wastes of time in the world, like discussing your favourite colour or deity or pizza topping. People should realise that and get on with their life.

Image

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WhiteWarlock
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Re: Matrix Mixer

Post by WhiteWarlock » Sat May 05, 2018 7:15 am

what about adding toggle switches or buttons on inputs
for some type of fast input mute function
not sure of your application or intention
easy enough concept for implementation
quad opamp would be good on output of that also
yet comprehend you probably want keeping it passive

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MKULTRA
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Re: Matrix Mixer

Post by MKULTRA » Sat May 05, 2018 12:40 pm

.
Last edited by MKULTRA on Fri Aug 24, 2018 1:47 am, edited 1 time in total.

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