Geekslutz DIY Summing Mixer

[d_cham]

Count me in too Tim!

Dennis Cham

[woofhead]

Hi,

Very interested and emailed you as well.Tanks


Mike

[svart]

If you guys need help, let me know.

a couple of db25 conns= 5$
some wire= 5$
5k1 resistors x 2 per channel= 5$ or so


About 15$ for passive summing if you have a junk case laying around.. just feed this back through your favorite set of preamps and voila!

You will add signifigant cost for a powersupply and output amps/trannys.

Just for fun, think paralleled 5532 ICs to drive an output transformer.. won't get much better than that..

[filthyrich]

Depending on the price, I'm also in.

[d_cham]

Tim, how many people are in already.?

Again one thing in most people's mind would be price. I thnk if we go in on, parts, power supplies and PC boards . . . a good working price would be in the $200 range and $500 max when you throw in all the Op Amps, output tranformers and rack case. It would also be great if Tim could put all of it in kit form and add a small mark up so save us all the hassles of finding the parts ourselves.

I am happy with just 16 inputs with an LCR switch on each input to 2 stereo outputs. Then again if a switch degrades sound we can nix that as well. No meters or monitor section anything to make it too complex to build. Bottom line it must above all have great sound. Afterall we are not after full function mixer, just a summing box to make our DAW mixes sound great. I assume most of us would have some sort of monitoring box already. Come to think of it a dual 8 into 1 summing box followed by a really killer preamp with tons of headroom and mastering grade step attenuators after that would be my ideal. It would be cheap and easy to build and do what we need it to do in the first place.

If we should add some tweak factor, maybe we can make it so that you can sub different Op Amps ( say 990, Avedis, or 5532s ) and different brands of output transformers to color the sound the way we want.

Just my two cents.

[delasoul]

so what was the price????

[franzzappel]

Tim, I would be in for two...

[Jon Kraft]

This sounds like an excellent idea. Im interested!

Thanks,

Jon

[shikawkee]

I'd be interested as well.

[mandzaro]

I'm interested too

What about switchable, different outputs transformers ?

Martin

[allbaldo]

I'm in if it stays on the simple side. I know it's hard to come up with even a rough figure as long as we don't have consensus on what features we all want, but I'd could swing a couple hundred bucks.

I'd like to see it stay simple. I'd love to see 24 tracks, but whatever works.

[zak7]

This is talking longer that the URS channel Strip Pro!

[Gonzalez]

I am also very interested!

[anthonyjeanne]

Hi Guys,

Long time reader, first time poster... Definitely keen on a summing kit too -

You guys are rock.

Anthony

[nerogtr]

any updates? this would make a great summer project.

[bleen]

My interest is definitely piqued!

[noize_organizer]

Hey guys !

If the kit is available for shipping overseas to Switzerland (West. Europe), I could be in as well ...

Let me know !

Peace

[delasoul]

i dunno what happened to tim.. its been a while. so after i got my lynx aurora 16.. i decided to take matters into my own hands.. and here is what happened..

[delasoul]

i bought the faceplate from guitar center for 8 bucks. drilled holes in the thing... ran a bunch of cat 5e wires into a circuit board, balanced, for each of the 16 channels. i bought a bunch of switches from my local electronics store, the plan was to put 32 switches,.. two for each channel (left right control, or both(mono)), but.. i bought out all of thier stock of switches.. so i realized that since i knew i would always use some channels for mono.. and some for stereo, i would save some money and only buy like 24 switches or so..

[delasoul]

my hands hurt after all that work.. but i kept going. since ive never done anything like this before.. i ran into some problems.. like how to attach the face plate to a chassis.. huh? i dunno.. i still dont know.. anyway.. here are some pics of the face plate labeled for which channel i wanted it to be for..

[delasoul]

i call it..

the sumthinrocken, 16 channels of analog summing.

its been finished for a while.. i still gotta take some pictures of the finished product now. its pretty ghetto in the back.. for the chassis i ran over to home depot and bought a big 4foot by 4 foot piece of metal, and cut and bent it into a decent chasis.. and screwed it into the face plate. the dsub conncectors connect straight from my aurora 16.

and it sounds big and shiny,... very analog.

[AMIEL]

Cool!! how it sounds? what re you using for make up gain?


Tim!!!! where are u? I think the list is longer!!!

[delasoul]

oohh.. right right.. make up gain..

yea, i have a p-1 and api 512c mic pres. but my friend usually lends me his p-1 so i can have a stereo pair for the mixdown. it sounds really nice, more depth.. and everything kinda has its own space.

[d_cham]

Very cool Delasoul!

Mind sharing what you did in more detail, schematics etc . . . imagine that a Folcrom for just a little sweat and at the fraction of the cost. Tim any news on your end?

[delasoul]

yea that was my goal exactly.. i mean im not all about the looks and things.. i was just tryin to get the thing to work. as far as the schematic it... it was slightly based off of the one tim drew up, and partly from another schematic i found on some website. ill try and post here. i hope i dont get in trouble for showing this.. or even making this.. cuz the schematic looks pretty legit.


i used all 1% 10k resistors and 250 ohm resistors as the end.. and that was basically it. theres roughly about 65 resistors in all.. its just a lot of soldering and wiring..

[anthonyjeanne]

Hi guys,

Found these schem's for summing mixers... My plans are to make a passive one with a line driver output or a passive one + two seventh circle audio neve clone preamps... Any thoughts on this idea before I start?

I'll post up info on my one as it progresses. I hope Tim comes through with a plan too!

Thought these links may be a handy:

Forssell Technologies - Great schematics for summing busses (balanced and unbalanced) and heaps of other stuff

Seventh Circle Audio - Awesome preamp kits.

Cheers
Anthony

[Tim Farrant]

Hi People

I am so sorry I have been absent from this, I have been flat out with just keeping up with my own stuff.

But, I have been thinking about the final design and it seems we might finally have enough interest to go ahead. Here's the idea;

16 inputs on DB25 with switches to select LEFT, RIGHT or BOTH
Main transformer Balanced output with Fader (mix)
Secondary electronically bal out with fader (monitor)
2 track (stereo) input on XLR that can be switched into the secondary output (without affecting main out) or can be added to main mix as expansion input.

Output transformers would be chassis mount, so you can change them if you want. Standard would be Sowter 8403X - a nice compromise between sluggish and pristine IMO. Kit can be supplied without the transformers.

Screenprinted 1U case and power supply included. 115V or 230V set up by wiring.

If this looks cool to everyone, then I'll price it.

Good work on your summer delasoul, I am sure you cannot get into trouble for taking circuits that are obviously freely published on the internet. Lets see the final schematic.

Tim

[Analogue Vanity]

glad this project finally grew wings. I'm in depending on price point. passive might be ok too for me. Thanks for your work on this

[AMIEL]

Hi Tim!!!

I still interested!! but please do it soon! I am ready to jump into a store to try a summing box.

[octatonic]

Originally Posted by Tim Farrant

Hi People

I am so sorry I have been absent from this, I have been flat out with just keeping up with my own stuff.

But, I have been thinking about the final design and it seems we might finally have enough interest to go ahead. Here's the idea;

16 inputs on DB25 with switches to select LEFT, RIGHT or BOTH
Main transformer Balanced output with Fader (mix)
Secondary electronically bal out with fader (monitor)
2 track (stereo) input on XLR that can be switched into the secondary output (without affecting main out) or can be added to main mix as expansion input.

Output transformers would be chassis mount, so you can change them if you want. Standard would be Sowter 8403X - a nice compromise between sluggish and pristine IMO. Kit can be supplied without the transformers.

Screenprinted 1U case and power supply included. 115V or 230V set up by wiring.

If this looks cool to everyone, then I'll price it.

Good work on your summer delasoul, I am sure you cannot get into trouble for taking circuits that are obviously freely published on the internet. Lets see the final schematic.

Tim

Sounds great.
Looking forward to getting a price.