# Dilor Litepak Control voltage



## Knave (Oct 31, 2009)

Anyone familiar with this system? 
I got my hands on an old (gov't surplus) single-channel 2400w dimmer and I'm wondering if it's useful for anything. 

Spec plate:

"Litepak dimming system
model: DMS-124
input 120vac
20 amp 50/60hz
max load 2400 watts
made in Canada by 
Dilor Industries Ltd."

There are a pair of 20 twist-lok plugs, the input plug is twist-lok as well (though it looks aftermarket) and the control cable (hard-wired) is M XLR. 

I've read a few thread on here about conversion boards for 10v systems -> DMX, but that doesn't do me much good unless I can figure out which voltage systemthis one uses (and even then, most of the boards are 8-channel, which is a bit much. I might just wire up a small controller for it and use it next to the booth.)


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## STEVETERRY (Nov 1, 2009)

Knave said:


> Anyone familiar with this system?
> I got my hands on an old (gov't surplus) single-channel 2400w dimmer and I'm wondering if it's useful for anything.
> 
> Spec plate:
> ...




It is almost certain to be 0-10 vdc.

ST


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## derekleffew (Nov 1, 2009)

Is this the same company that touted "self-trimming dimmers" in the early 1980s? I distinctly remember a representative at a trade show saying "go backstage at any Broadway show and you'll find a Light Palette connected to Dilor dimmers." Having never heard of the brand before, I was skeptical.


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## STEVETERRY (Nov 1, 2009)

derekleffew said:


> Is this the same company that touted "self-trimming dimmers" in the early 1980s? I distinctly remember a representative at a trade show saying "go backstage at any Broadway show and you'll find a Light Palette connected to Dilor dimmers." Having never heard of the brand before, I was skeptical.



Bash had a few Dilor racks, and PA had a few 12x2.4kW packs, but they were not pervasive on Broadway.

Dilor had a 4x2.4kW dimmer module designed by Sean Adkins, but I do not think they were "self trimming". 

Once the LMI L86 (and subsequently ETC) high density touring racks came along, they pretty much replaced the hodgepodge of dimmers previously used on Broadway.

ST


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## church (Nov 1, 2009)

I think Gordon Mcleod who posts on here knows about DILOR


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## derekleffew (Nov 3, 2009)

It appears Dilor Litepak was absorbed into Douglas Lighting Controls. Someone in the company probably still knows something about their theatrical lighting controls.


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## gordonmcleod (Nov 6, 2009)

My suspision is that it is 0-12vdc control as during the era that dilor was around that was the common voltage up here
Most of the Dilor stuff was self calibrating and overall well built


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## JAJ (Dec 23, 2011)

gordonmcleod said:


> My suspision is that it is 0-12vdc control as during the era that dilor was around that was the common voltage up here
> Most of the Dilor stuff was self calibrating and overall well built


 
Unless that particular unit was built for a customer that specified a custom control voltage, it's a 0-10v DC control signal. Everything we built was 0-10v because it made troubleshooting easy.

Backing up in this thread a little way, Steve Terry's recollections are interesting. In 1980 or 81, Dilor had dimmer racks out on Broadway with Bash and Four Star. The market share number that sticks in my mind is 28% of shows running that year were lit with Litepak racks. It wasn't until the Strand CD80 came along and cut the price per kw in half that the market changed. I don't remember much about Lighting Methods Inc (LMI) but I do remember the emergence of a new company called Electronic Theater Controls (ETC) as a player. IIRC, their initial product was a computerized console that was programmed in Fortran. 

The quad dimmer module that Steve's referring to is a bit of a mystery to me, only because I can't remember if it was a quad or a triple. In any case, it was designed after Sean Adkins joined Dilor. As with every Dilor dimmer, the electronics, noise and heat were my responsibility, while the packaging was a team effort by Sean, Paul Humphries and myself. Sean's experience with Bash in NYC was invaluable because he'd seen all the bad things that could happen to dimmers in rental and touring service, so we came up with a pretty robust product. 

All of the Dilor dimmers, from the first raw aluminum prototype to the architectural dimmers that revitalized the company's fortunes and led to the sale to Douglas, were "self-trimming".


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## derekleffew (Dec 23, 2011)

JAJ said:


> ... All of the Dilor dimmers, ... were "self-trimming".


For us neophytes, can you explain first what "dimmer trimming" is; and then, exactly how the unit "self-trimmed"? 

Is it something like "trimming a wick" (which I understand STEVETERRY, SteveB, and select others used to do) ?

[IIRC, Dilor LitePak dimmers were anything but! The rolling racks resembled the size, shape, and weight of today's Knaack box, and 12x4kW was a common size, I believe? They were sort of a cream/yellow color?]


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## jstandfast (Dec 23, 2011)

I remember well the Dillor Racks, went to Bash in '89 or so (to train on MOTO Lights) and saw a big parking area full 0f Dilor racks. I recall being told that if they thought a show was going to run long, it got Dilor dimmers from the start. I think I saw my last one come out of a truck in '92 or '93 or so......


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## DavidNorth (Dec 23, 2011)

I remember them too. After they were popular in NY, we bought a couple of them for rental and production use at Stageworks Lighting in Raleigh.

They were 72 x 2.4kW with built in fused disconnects and Pyle National outputs. The modules were 3 x 2.4kW with status LEDS and bump buttons. Yes, also 0-10vdc but I put early BASH DACs on them to run DMX.

There was a single screw pot on the right side of each dimmer that adjusted trim. I once had my arm in the rack setting trims when my pager, set on vibrate, went off in my pocket. I jumped about 10 feet.

We bought all the remaining spare parts plus schematics from Canada. I spent a lot of time maintaining the racks and even rebuilding the one from Tulsa Ballet that got dropped off a truck that also had a botched set of control wires mods to support an Omega on Centronics connectors.

These racks did not tour well. I carried spare spare parts on tour including power cubes, fans and modules. Certainly their age when we got them didn't help but the frames were by far not strong enough for the weight....and they were top heavy on narrow wheels sets. Just had to be careful getting them on and off the truck.

With all that, I did like them.

David


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## JAJ (Dec 24, 2011)

derekleffew said:


> For us neophytes, can you explain first what "dimmer trimming" is; and then, exactly how the unit "self-trimmed"?
> 
> Is it something like "trimming a wick" (which I understand STEVETERRY, SteveB, and select others used to do) ?
> 
> [IIRC, Dilor LitePak dimmers were anything but! The rolling racks resembled the size, shape, and weight of today's Knaack box, and 12x4kW was a common size, I believe? They were sort of a cream/yellow color?]


 
The cream with brown lettering 12 channel Litepaks were lighter, smaller and easier to use than what came before. If you ever hooked up an EDI Scrimmer portable dimmer, you'll know what I mean. Our initial customer was a lighting rental shop in North Vancouver and our goal was to have a product that was lighter, better and more reliable than his stock of Scrimmers, Electro-controls and Strand equipment. 

As I understand it, the word "trimming" did originate with wicks, although in the world of electronic dimmers, it took on a whole new meaning. I started my "career" by repairing the aforementioned gaggle of Strand, EDI and EC gear for said rental house. That these dimmers were electonic and they dimmed lights was their only resemblance to modern dimmers. The control circuits were rudimentary on an epic scale. Trimming was the process of compensating for drift in the control components (thankfully, they had transistors by then) and for any minor changes in the environment - temperature, humidity, phases of the moon, etc. Each dimmer had at least two trim pots. One for the top end of the curve and one for the bottom. They interacted, so you had to set one, set the other then repeat until you had a dimmer output curve that was as close to useful as you could make it. The chances that the next dimmer you trimmed would curve-match were minimal. Some dimmers snapped on, some had massive hysteresis, some drifted while you adjusted them. It was not a pretty sight.

So what was "continuous self-trimming"? Dimmer curves are all about timing, so if you can conjur up a reliable timing circuit, you get a reliable dimmer curve. CST was the application of digital integrated circuits to dimming. I came up with a noise-tolerant zero crossing detector using a Motorola analog IC, hooked it up to a phase-locked-loop using another Motorola CMOS chip, and built a rock-steady 8 bit linear ramp. Each step was 0.7 degrees of conduction regardless of incoming line frequency (good for gen set operation), and with the newer technology it didn't drift. If it tried to drift, the PLL circuit self-corrected ("self trimmed"). You could vary the temperature, the line frequency and the phases of the moon and your entire dimmer bank would continue to deliver the same curve with all dimmers matched. 

While they were self-trimming, they weren't "trim-free". All Litepak dimmers had one trim pot that set the control voltage scale to 10v for full on. That was it. Early models had linear-phase curves and no output regulation. Later we added a square-law curve and full regulation.


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## JAJ (Dec 24, 2011)

DavidNorth said:


> I remember them too. After they were popular in NY, we bought a couple of them for rental and production use at Stageworks Lighting in Raleigh.
> 
> They were 72 x 2.4kW with built in fused disconnects and Pyle National outputs. The modules were 3 x 2.4kW with status LEDS and bump buttons. Yes, also 0-10vdc but I put early BASH DACs on them to run DMX.
> 
> ...


 
Ahh! So the modules were triples! I couldn't remember directly, but the packaging logic we used would have led us to a triple and not a quad. Usually quads were one phase per module, and triples would be three phases per module. For permanent installations, it didn't really matter and quads were cheaper to build. However, while we did permanents, our customer base included a lot of rental operators, so we had to meet their needs too. 

I don't know what it's like now, but in those days generators ran best if the loads were balanced across the phases, so stage electricians balanced the loads as part of the setup. If a dimmer module failed, all of its circuits went dark. A heavily loaded single phase quad took 80 amps of load off one generator leg if it failed, where a heavily loaded three-phase triple took 20 amps off all three legs. I'm not saying we never made quads, but triples make the most sense to me now.

As for robustness and reliability, the early racks were the best. We computed all the loads on the steel frames and components so that they wouldn't bend or break under rough handling but the biggest issue was vibration from miles on the road. That would crack welds and fatigue the wiring, and there wasn't a lot we could do about it. We braced things as best we could, but the racks had to be easy to service when they were hooked up, and that limited our options. 

The heaviest racks we ever built were a "custom" for Four Star (I think) and they came out with the model number on the nameplate "RMRDR" followed by a number. It stood for "Real Man's Rolling Dimmer Rack". They were massive. We ran our own silkscreening operation for labels, so we labeled a few as "Heavypak" for a joke, but never shipped them anywhere.


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## NormS (Jan 15, 2012)

There are still a few RMRDR ghosts lurking.


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## derekleffew (Jan 15, 2012)

NormS said:


> There are still a few RMRDR ghosts lurking.


Well, as long as you're here...some things I've been meaning to ask JAJ:
1. Did Dilor ever pursue or implement an "other than analog" control protocol? Hard to complete with the big boys' Light Palettes if one couldn't listen to CD80.

2. How/why did Dilor leave the stage lighting industry? I can't imagine imagine there could be something more lucrative than being a dimmer manufacturer, just ask TTI and EDI.


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## JAJ (Jan 17, 2012)

NormS said:


> There are still a few RMRDR ghosts lurking.


 
"NormS" eh? Did you perhaps work on building them?


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## JAJ (Jan 18, 2012)

derekleffew said:


> Well, as long as you're here...some things I've been meaning to ask JAJ:
> 1. Did Dilor ever pursue or implement an "other than analog" control protocol? Hard to complete with the big boys' Light Palettes if one couldn't listen to CD80.
> 
> 2. How/why did Dilor leave the stage lighting industry? I can't imagine imagine there could be something more lucrative than being a dimmer manufacturer, just ask TTI and EDI.


 
1. we built an analog demux that worked properly with the serial analog protocol for the CD80. We didn't do our own.

2. a combination of factors. First, we had a new President that didn't understand the industry, so when we were awarded the Tampa Bay Performing Arts Center contract, he refused to sign. Then we came under enormous price pressure from the CD80 in the touring markets in California and New York. The final nail in the coffin was the bankruptcy of the general contractor on the Red Deer Arts Centre project. They filed literally the morning that $250,000 worth of dimming and control gear arrived on the jobsite and we never saw a penny of it. I've made a career subsequently as a corporate repair man, fixing broken businesses. Dilor was my first workout and I left in 1988 once I'd got it refinanced and profitable again in the architectural lighting business.


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## NormS (Jan 18, 2012)

JAJ said:


> "NormS" eh? Did you perhaps work on building them?


 

That would be correct.


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## JAJ (Jan 19, 2012)

NormS said:


> That would be correct.


 
Aha! Well then, the most pertinent question for you: are you still fixing planes?


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## NormS (Jan 19, 2012)

JAJ said:


> Aha! Well then, the most pertinent question for you: are you still fixing planes?


 
Yes, still working on flying machines. I've been trying to find you and Sean...... so I googled "RMRDR"....


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