-10v demux

[sandall]

My local theatre still uses an old Strand Environ dimmer for house-lights, controlled (HTP) by a fader & also by DMX from a channel on the desk. The ancient demux that was left behind when we changed to ETC dimmers many years ago has apparently died & I'm really struggling trying to source a (preferably single-channel) -10v demux to replace it.

 

In the past I've used several Soundlight modules to make up specials, but (a) they don't seem to offer -10v versions & (b), although in theory they are distributed by Lightfactor, trying to access the Lightfactor website just takes you straight to Eaton's Zero-88 pages, with no obvious links to Lightfactor. An old BR thread came up with a Ben who used to build DMX modules in the UK, but his website hasn't been updated since 2005, & again he didn't offer -10v.

 

I realise it might be cheaper to just replace the dimmer (though it would still need to be analogue, & would still need its own demux), but building a DMX PCB into a project box would be a lot easier.

[jonhole]

Our Zero 88 Demux 24 can output as either negative or positive (+/- 10V)

[sandall]

.

Our Zero 88 Demux 24 can output as either negative or positive (+/- 10V)

True (I have an idea someone has offered a 2nd hand one), but maybe a bit OTT for a single channel, though it would offer lots of redundancy :). I was rather hoping that someone would know of a dinky little PCB that would go in an Eddystone box.

[themadhippy]

Off the wall idea,one of those 3 channel rgb led controlers that are all over ebay and an op amp inverter to get the - output

[Jivemaster]

Off the shelf item -there are a few multi channel -10v decoders, use one channel

"Soldering iron" solution, use any +10 decoder and an inverting op amp

 

"Procurement department" solution, buy a DMX dimmer of suitable rating.

[kgallen]

"Procurement department" solution, buy a DMX dimmer of suitable rating.

 

Something like this maybe:

 

https://www.stage-electrics.co.uk/shop/sales/lighting/dimmers/show-lighting-dimmers/portable/product.aspx?code=469-2045&nr=true

 

or one of the cheaper clones like this:

 

https://www.thomann.de/gb/botex_up1.htm

 

 

 

[ianknight]

"Procurement department" solution, buy a DMX dimmer of suitable rating.

 

Something like this maybe:

 

https://www.stage-electrics.co.uk/shop/sales/lighting/dimmers/show-lighting-dimmers/portable/product.aspx?code=469-2045&nr=true

 

or one of the cheaper clones like this:

 

https://www.thomann.de/gb/botex_up1.htm

 

Can I just say... from passed experience, if you're on a budget but looking for longterm life - don't buy these as they're not especially durable. You would be better talking to Anytronics and finding where you can buy a ProDim with a DMX input. They're rock solid, brick privvy style units and will serve you well for ages.

 

Anytronics ProDim

[Richard P-W]

 

Can I just say... from passed experience, if you're on a budget but looking for longterm life - don't buy these as they're not especially durable. You would be better talking to Anytronics and finding where you can buy a ProDim with a DMX input. They're rock solid, brick privvy style units and will serve you well for ages.

 

Anytronics ProDim

 

Just to counter this - we've had 2 ProDim units on houselight duty in the past 15 years and both suffered catastrophic internal failures. Now use a Strand which is working fine, but not as neat as a hardwired box. Probably just jinxed myself now!!

[sandall]

Off the shelf item -there are a few multi channel -10v decoders, use one channel

"Soldering iron" solution, use any +10 decoder and an inverting op amp. "Procurement department" solution, buy a DMX dimmer of suitable rating.

 

Off-the -shelf solution preferred - do you have any examples you can point me at (preferably not 19" rack-mount)?

 

After decades of everything electronic around the place being home-made, they want to avoid "soldering iron" solutions, because when they go wrong nobody knows how to fix them (I'll make an exception for putting a module in a box, as long as the paperwork is sound).

 

Re "Procurement department" - there are plenty of single-channel dimmers around, but how many will take analogue and DMX inputs, happily drive a mixture of LED, birdie transformers & halogen, & be totally trouble-free for 30+ years?

 

E2A: I've had a couple of analogue ProDims for years as follow-spot dimmers- the only problem being one where the triac was within striking distance of one of the top-panel fixing screws (tripped the MCB & burnt a piece out of the screw, but is still going fine).

 

 

[alistermorton]

We use an Act6 digital for houslights. Takes an analogue input from the face plates, but when the DMX starts up that has precedence, takes over and the desk has control. So while the lighting desk is off the houselights behave, to the casual user, like ordinary room lights, they just switch them on and off from the wall plate. For shows the lighting desk takes over automatically.

[DrV]

Nobody seems to have suggested repairing the existing unit. A single channel demux is not rocket science and the chances are it is repairable without documentation. Drop me a pm if you'd like to try that route - I'm near Epsom in Surrey.

Dave

[sandall]

Thanks Dave (& Andy)

 

I've just found out that the offending demux is actually one channel of a 1990-vintage 120+ way Arri demux built into in a 4u (or 6u) Donmar box - all the other ways became redundant when the dimmers were replaced by Sensors a few years ago. The problem may of course be something simple, & the 2/H Zero-88 is a possible solution, but I'm still hoping someone will know of something a bit smaller.

 

Re replacing the dimmer - because the Environ handles whatever sort of load that's hung from it & appears to be totally bomb-proof, the thought of replacing it with something modern has had a firm thumbs-down from all concerned.

[ianknight]

 

Can I just say... from passed experience, if you're on a budget but looking for longterm life - don't buy these as they're not especially durable. You would be better talking to Anytronics and finding where you can buy a ProDim with a DMX input. They're rock solid, brick privvy style units and will serve you well for ages.

 

Anytronics ProDim

 

Just to counter this - we've had 2 ProDim units on houselight duty in the past 15 years and both suffered catastrophic internal failures. Now use a Strand which is working fine, but not as neat as a hardwired box. Probably just jinxed myself now!!

 

I laughed when I read this.. I know that feeling too :)

[Kazeja]

Have a look at

 

http://www.dmxprojects.com/projects_dmx_analogue.html

 

It is a standard 0-+10v but has a +10v REF which if you use as the 0v and select the invert function, allows 8 channels of 0--10v which should be OK for your Environ.

 

K

[IRW]

Have a look at

 

http://www.dmxprojec...x_analogue.html

 

It is a standard 0-+10v but has a +10v REF which if you use as the 0v and select the invert function, allows 8 channels of 0--10v which should be OK for your Environ.

 

K

 

+1 for Ben's board. I contacted him three or four years ago about buying some of his boards to fit into some Betapack 2's. He was really helpful, and even helped me out with a variant that used rotary switches instead of dips, which enabled me to fit them into the Beta's and have them almost look like proper Betapack cards, with a bit of careful use of protoboard and custom metalwork on my part. IIRC, I don't think he supplies them ready made anymore, but he was happy to send me the PCB's, and a full farnell shopping list for components.