Passive Summing Box - To PCB or not to PCB

[enthalpystudios]

brand new, only like 7 days left on the trial.... try these:


http://www.enthalpystudios.com/diy/passive8chanwithtraces_12.cdr

http://www.enthalpystudios.com/diy/passive8chanjustholes_12.cdr

exported as v12

excuse the mess;]

just wanted to try and get a feel for it..... mostly to see if the traces are acceptable spacing/size wise. the holes will fit, like i said, by just not having support holes for a couple of the xlr connectors.

still makes for quite a long pc board at 16 inputs tho.

billy

 

[kruz]

Thank you billy.. they work now.
now.. just to put fuel on the fire here..
do we really need the LR-Mono switches? i mean.. how many mono tracks we are going to mix?
I see just the bass track in the middle.. maybe the kick track too.. but the rest i usually have stereo tracks, even a guitar slightly panned to R needs a stereo bus..
So.. is it worth to spend time and money on implementing the switching?
just my idea..

 

[enthalpystudios]

no probably not ;]

IMHO, this thing should be all out, mono switches, assign switches, relays, psu, or it should drop dead simple. which is nice. and *cheap*. and *fast* with a pcb. odd->L, even->R. perhaps some extra pads before the output connectors for those who want to hook into an active summing card.

if super simple, still IMHO here, I do think a quick switch on the first two inputs would be nice to route 1/2 direct to the outputs for normal monitoring during tracking, etc.

what might be even smarter is to switch between 2 sets of outputs, one for monitoring that gets a signal straight from ins 1/2, and on set that has the bussed inputs. I think that would be smart.

 

[kruz]

i like how you think, billy :green:
i'm totally down that route

 

[enthalpystudios]

right on ;] i just wanna save 2 patch cables, and for some it may be saving reaching behind a rack or desk or whatever, which no one likes to do.

just keep in mind i don't necessarily know how to go about doing these things. ;]

But now I'm thinking that after switching over to mix/summingbox outputs mode, and your monitors still need to be routed. gotta listen on something when you're in passive summing mode!

I guess this is just something people can do individually anyway to suit their needs.

sorry, i need to stop adding wierd options and crap to this thread.

i'm going to go solder like a good diy

billy

 

[Matt Syson]

Hi Billy
This could go on for days so it is probably an idea to make up a panel and leave space for more switches so they can be added when ideas come to you.
UK03*** The 1 pole EAO has 6 pins, 2 for the lamp, 2 that are closed with the switch up and 2 that close with the switch down. They do not have a 'common' connection like a typical toggle or slide switch. (Check exact spec of switch though, there are variations).
If the circuit is suitable you can use it such that the contacts make an audio circuit in one position and when operated the other way the alternate position can short a switching circuit. Thus you can conspire to short out the LED (make it go off) at the time when the audio circuit is open. I would assume that the LED is fed from say 12 volts via a suitable resistor (normal volts across an LED is 1.8 - 2.2 volts depending on colour) thus the current used will increase a bit with the LED 'off'.
Matt Syson

 

[enthalpystudios]

well, i suppose with those switches and relays all the slightly more complex wiring arrangements get simpler in some ways.

i'm interested to hear what peoples think about some of this stuff. the mono stereo thing isn't totally necessary to me, but i do have a feeling that having a couple mono inputs just for the standard mono stuff (kick/bass mono bus, lead/center vocal mono bus or something) could sum to simple mono better in analog with matched resistors and all.....


i dont really know though. i have too much time on my hands i think. thoughts running wild about a project that I cant afford an enclosure for ;]

..... back to more soldering, have too much crap on the bench and a band coming in in a week and half.

 

[jtoole]

wow. excellent to see so much activity and ideas in this thread :thumb:

I'm going to try to give me 2cents on some of the items discussed since my last post. Hopefully it won't be too confusing without specifically quoting each person.

Regarding db25 vs. xlr, etc... I don't personally have a need for db25, and I had thought the easiest solution was to avoid any PCB mount footprints and require that I/O is wired to pads or headers - this would allow users to choose db25, xlr, or TRS.25" as required for each application. Is the primary reason some of you are interested in a PCB is to have PCB mount i/o? About fitting both db25 and xlr on a PCB - I wonder if you could achieve this by changing the boards rotation depending on desired format - mount xlrs along back and db25 on front or sides...

Also, keep in mind that using headers vs. pcb mount would likely result in a much smaller PCB = lower fab cost.

I would take a similar tact w/ switches - my preferences is to not have any switches (although I like the bypass 1-2 -> output idea - sounds useful). I was thinking that, like the i/o, switches could be wired from pads so users like myself could hardwire a particular configuration (mono vs. stereo, # of channels perhaps) instead of installing switches.

There was mention of LEDs and relays - up to this point, I've been thinking this is a fully passive design with no power supply... how will that work out?

I will _hopefully_ have a sample schematic and possibly a PCB layout attempt some time soon... I'm working w/ a friend on this - he's more experienced at layouts - and we've just had to find time to get together and put something down... of course - Don't let me stop anyone else from doing the same - if someone else has a PCB layout they like, I'd be happy to help w/ that too!! :grin:

...

Josh

 

[radiance]

Just some general thought about the relays: I think that when designing the pcb we should make it accept both normal and SMT relays.
You can get these smt relays for cheap on Evilbay. For example I bought 800 dpdt 24v Omron smt relays for $90.

 

[Matt Syson]

Hi
Is there any chance of someone drawing up a 'block diagram' rather than a detailed schematic to get the overall picture of what (we) want to make.
This would be less arduous than doing a schematic at this point. Even a scanned version of a pencil sketch would be good.
If push switches are used they can be obtained with up to 8 pole changeover quite easily and require no power. (Folcrum) Going the relays route may be interesting in that it would be possible to do 'tricks' by using a diode matrix for example to have semi preset configurations with a switch or two placed on the console or nearby to select 'record mode' and similar frequently used permutations, even monitoring. The audio can still be passive of course.
Matt Syson

 

[Guest]

I am greedy - I know what I want to do but don;t have the technical knowledge to do it
Andrew over at Purple Audio is on my wave length
http://www.purpleaudio.com/Product/4RUMaster.html
http://www.purpleaudio.com/Product/Super8.html

 

[analogical]

Don't care what conn. you use, I will modify to taste, but bump on the pcb whatever y'all figure out...

 

[jtoole]

At this point it looks like we're going with a fully passive summer pcb w/ a dual DPDT switch configuration (assign L, assign R) ala the NewYorkDave pdf (Much Thanks!). In addition, we're thinking of adding a 4PDT switch to bypass In1+2 to the output for quick bypass when not in use. The plan is to include PCB footprint for pushbutton style switches, but the builder could choose to hardwire to save cost if desired.

Audio I/O will be through pads that are spaced .1", w/ signals every other pin, so either .1" headers or 5.08mm screw terminal blocks (every other pin) can be used at the builders choice. Also the board will have bypass caps to ground that can be populated optionally or jumpered.

I'm beholden to a friend who's doing the board layout, and we've just been working out some details and making some choices. I gotta say I really appreciate all the time he's taken and can only expect so much of his free time.

I know some are interested in an active setup, with more bells and whistles, but we've decided to go with something simpe and keep cost low. I hope at least a few others would be interested in this kind of configuration.

Josh

 

[soundtrack2life]

If a PCB was not used other that a copper wire what would be use for a buss bar in a summing mixer. Does anyone have a spec?
Joe

 

[NewYorkDave]

What?

 

[soundtrack2life]

should of read

If a PCB is not used, other than a copper wire what would be use for a buss bar in a summing mixer. Does anyone have a spec or a part #.
Joe

 

[lofi]

what happened to this project? did the pcb get designed? if so, who do i mither to purchase one?

 

[jtoole]

[quote author="lofi"]what happened to this project? did the pcb get designed? if so, who do i mither to purchase one?[/quote]

lofi -

Yes, we are on the second rev of the PCB now. Unfortunately like many labors-of-love, this project has taken backseat to our day jobs, so it hasn't moved too fast, but we're still here.

We are putting an order in for 2nd rev PCBs soon, drop me PM if you want details on ordering...

Thanks -
jt

 

[danjpiscina]

I can tell it's been a while but I figure I'll give it a shot! Is someone still making PCBs for this passive summing box? I want to build one with pushbuttons! Can someone send me in the right direction? Thanks!

Dan P.

 

[ninetysixk]

I'm interested too. Can someone give me a heads up if they are still around?

Cheers