Mixer to two devices?

[stosostu]

Lee Cardan's question about patch bays reminded me of an issue I have not yet solved.

I want to use one 24 channel mixer, but connected to both a 24 channel tape machine or a 24 channel work station. Short of repatching 24 ins and 24 outs every time I want to go from analogue to digital, or the opposite, does anyone have a suggestion to solve this?

[gigpiglet]

hmmm
yeah...
without a multi pin.. not really that i ever thought of.

interested to hear other folks thoughts.

you could have a patchbay in the chain that has a normaled output (so the through to the one machine, and the normal to the other) so it would go to both all the time

thats how im doing it.
but im not saying thats right (and its an aweful lot of jacks!)

[Chinagraf]

Solder up some y-cord splits? It would depend on the impedance the group or direct outs of the mixer want to see, and the input impedance of the tape machine and daw in parallel. I vaguely think the formula is z1 x z2 divided by z1 + z2? In this case Z1 would be the input impedance of the tape machine, z2 the daw...?
Cant remember for sure. Is Rob out there somewhere?

[Ben M]

Hey Bob, have you considered the Endless Analog Clasp system?

http://www.endlessanalog.com/
http://www.youtube.com/watch?v=hEdDbhizIDs

I'm thinking that these have been out long enough now to get much cheaper secondhand or street...and you'd always have your machine and DAW locked together...which is often a massive plus.

[stosostu]

Since the system is not intended to have both connected at the same time, just either, or, I had thought of 24 relays all operated by a single switch, sort of like the audio/video switchers used in broadcast. I had a 12 way one a while ago but gave it to another studio owner. Any thoughts on that?

[rob]

A relay box will do it. You just need to use good quality sealed relays and consider the time and expense to build it. 24 channels is 72 connectors to get all the I/O presented. If these are XLRs. there's ~ $350 just in connectors, add a box and relays, PSU, case and labour and you have considerable cost.

Cheapest option is Y splitting the output of the console, say on a second patch bay row. The only thing to be aware of here is that some devices when powered off will place a non linear load on the split causing signal distortion, you need to test the devices you'll be using to see if this applies.

Another approach is to place the two machines inputs on multipin connectors and the console outs also on a multipin connector, then link them using multipin patch leads. DL connectors will deal with 24 channels on one connector but are expensive ( may be around the same total cost as a relay box ). Dsubs wired to the Ta@#$% standard will do 8 channels on one connector. You can make a patch lead with crimp plugs and ribbon cable, cheap and fast and perfectly fine for balanced lines if kept to shortish lengths. This allows allows you to patch in banks of eight so you can simulaneous route some channels to tape and some to DAW.

[NYMo]

Otherwise use a Yamaha 2416 or 3216....they have dual Xlr inputs that are switchable .
I use a 1516 and have my daw in one input and my 16 tape returns in the other !

Cheers

[stosostu]

At this stage I am leaning towards the relay box, using DSubs for the I/O connectors and DPDT relays so that I get good separation between the I/Os of each machine, it will need 48 relays but I have located some suitable ones at a 'reasonable' price, and those plus a power supply, a box and the DSubs should come in at around $200 - $250.

NYMo, I did a search for Yamaha 2416 and 3216 and all I got were some DSP cards, which I don't think were what you were referring to, is there more to the model number or am I missing something?

[rob]

If you use DPDT relays then you only 24. One bank of outputs can run off the normally closed contacts. This also means you can at least talk to one machine with a failure of the relay supply. And while there might be a little bleed into the non selected outputs as they are just hanging open circuit it really isn't an issue as you are using this machine when you have selected the audio away from it.

[stosostu]

Thanks Rob, I need 48 because I have to rout 24 outputs to each machine and 24 inputs back from each machine. I want to use DPDT as then I can make/break both sides of the balanced lines. When I worked on the OTHR radar we used similar relays and achieved better than 90dB separation between NO and NC contacts at RF so I would expect at least as good, if not better at audio.

[rick]

I have seen a bunch of abc installations over the years and at auction that had multirack relay boxes

the rest of us used patch bays or edacs or both

but more importantly when I sat down to type this post I had a hot bowl of minestrone soup and two fresh bagels to dip in them , I only feel like I could have had time to eat one bagel

but the other one is nowhere to be seen ..
still most of the soup left ... ????

me thinks if your building multiple boxes can you build me a bagel copier .. ?

[stosostu]

You see, Rick, the difficulty here is the fact that you only 'feel like' you had time to eat one bagel, but as Einstein explained, time is a flexible element and if the minestrone and the topic you were typing took precedence in your mind for a while, then the missing bagel may have been consumed during that time without affecting the time that you had originally allocated for bagel eating. In fact it is likely that bagel eating, minestrone drinking and typing all got intermingled and the time became inconsequential, conflated, no less.

Those old ABC relay boxes are what gave me the idea for this in the first place. I had one a while ago, that I wasn't using so I gave it to another engineer who had a use for it at the time. See, there it is again, time interfering with the relevance of whatever it is we should be doing. My coffee is now ready.

[rob]

and now strangely I need to build a multichannel relay box for a client .... hmmm

[stosostu]

Very Interesting.................but stupid (Apologies to Arte Johnson)

[rob]

So I'd really like to use four pole relays if I could find suitable quality ones and find an off the shelf pcb.... dreaming I suspect

[Drumstruck]

Very Interesting.................but stupid (Apologies to Arte Johnson)

And now, here's the right-on Dan Rowan and the more-on Dick Martin


At least 2 of us still remember that show Bob

[Alastair Reynolds]

Not my favorite solution , but workable is D-25 Printer switches using XLR to D25 Leads , Ta@#$% or otherwise.
You'd need to try one and see what the distortion/crosstalk/frequency response etc etc is like. Given the short internal cable lengths it may be acceptable. I have a stack of them here you can have if it works.
You could then switch 8 channels at a time . Certainly cheaper than Relays, though there may be audio degradation.
Really something to test before committing to.
Failing that you could remove the switch and just use the Ta@#$% D25 as the mutipole connector.
Just a thought

[rob]

thanks Alistair
my requirement is for an device with switchable inserts so a change over switch doesn't quite do it.

might be time to lay out an pcb ( or another one ... eh Rick! )

[Alastair Reynolds]

I suppose the other way you could do it with would be to use a full normalled bantam patchbay with monitor jacks and disconnect the monitor jacks from the middle row and connect them to the alternative machine (The one you use least ) and buy a bunch of bantam patch leads and plug in the alternate machine when needed. At least when you're in "Normal Operating Mode" it would be clear and when going alternative just plug in. would give you some nifty cross patching capabilities too. Or send Rob a case of Red Wine and encourage him to lay out a PCB with a bunch of relays and find an inexpensive relay source from china and bring it out to D-25s.
No real cheap way of doing it unfortunately

[stosostu]

Or send Rob a case of Red Wine and encourage him to lay out a PCB with a bunch of relays and find an inexpensive relay source from china and bring it out to D-25s.

This has obvious merit.