Time Square's new dimmer
- Thread starter gafftapegreenia
- Start date
I'm very curious as to why they even bothered installing a totally non-standard RJ14 TELEPHONE jack on a device getting DMX.
I cannot imagine it would have cost anything more to use an RJ45 Cat5 connector, which at least can use a cable that is compliant with the DMX standard. Going to phone wire puts them into a scenario of having to explain to a lot of users why the dimmer packs are acting flaky, all because of incorrect cable type.
Plus, it's using a 15 amp Edison connector with a feed through female for daisying the power out to another unit ?. So you load this puppy up to full capacity with 2 S4's @ 575w ea. (9.6 amp load at 120v ?), then feed a 2nd pack doing the same ?. I'm a little unclear on the concept.
It is Times Square though....
SB
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It would have added approximately $20 plus the hole punch programming on the CNC machine.
Hey team I just bring these things to your attention, I don't always say I love 'em.
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Umm... Hello !, and Yes, of course that would be the purpose of the female, and I didn't even think of that. I had just completed a very large glass of white wine when I typed ignorantly away (as sad explanation as to why my brain was turned off.
SB
I'm not going to stand up on Van's soap box to defend them but it doesn't seem like THAT bad of an idea to me.
If you run real DMX cable from the console to the first dimmer and you only use short jumpers with the phone line to daisy chain a few of them together it should work just fine. No you can't run 50' runs between units but that isn't who they are designing this product for. This product is for little rigs like small DJ setups and touring church choirs... Customers that don't need the dimmers more than a few feet apart. No it's not for most of us on CB, but I can definitely see a target market that will buy them and they will work just fine for.
If you run real DMX cable from the console to the first dimmer and you only use short jumpers with the phone line to daisy chain a few of them together it should work just fine. No you can't run 50' runs between units but that isn't who they are designing this product for. This product is for little rigs like small DJ setups and touring church choirs... Customers that don't need the dimmers more than a few feet apart. No it's not for most of us on CB, but I can definitely see a target market that will buy them and they will work just fine for.
NO,NO,NO,NO...
How many times do we have to hear about all the problems using Mic. cable for DMX, all a result of the manufacturers getting cheap and using 3 pin XLR ?. Now we have to listen to complaints from folks using telephone wire ?. Jeez....
If I wanted to spend my time watching stupid people asking stupid questions about lighting control, I'd be over on a Google X10 forum....
FWIW, my space often uses a very good audio company out of Staten Island, NY, for stuff we don't have or if the producer wants a particular system (Nexo, Yamy Digital, etc...). This same company got the not-so-bright idea to branch off and do some lighting, Martin 250's, some cheapo LED Cans, etc... They also purchased a Road Hog. They also don't (yet) get just how complicated this stuff is and how many, many ways it can get screwed up !.
They came in last week for a rental with pretty much everything they own, lighting-wise, setting up 2 days early for a rehearsal. They were not actually prepared to set up everything, as they usually send their Hog DMX down their audio snake, and they were not doing audio - so no snake. This is also a practice our audio guy doesn't like on our house system, for many, many good reasons (we never allow this).
ALL of the data control cable between fixtures was microphone cable. The lighting guy from the company had NO clue. He was using our 5 in-house Studio Spots and wanted the fixture manual so he could figure out how to patch to the Hog. He was very impressed when we pointed out that as High End makes the Hog, there's a dead certainty that the config. for the SS's was already in the console. Woah !, that was like, SO COOL !.
This is the very same kind of company that will try to save some money and buy these TS dimmers and wonder why the frigging stuff doesn't work when using telephone cable.
Other then that, it looks like a fine product and they did put in 5 pin !.
SB.
JD
Well-Known Member
Hee hee.. There is a great irony there. Most sound snake is actually data cable and is 110 ohms with a foil shield! Interesting from that perspective only.
Lighting DMX control should never be run through the audio snake IMHO, as it introduces all sorts of bad scenarios. Stage boxes often common or case ground pin one, thus making an electrical tie between the lighting and sound companies. Even when this is not the case, there is a great surface area exposed from one foil shield to another, so even if you have electrical isolation, you have a capacitive cupping between the two.
Now, on to Times Square: I am sure they are a lot better of a company then when I did business with them back in the 80s. Back than, they were not known as er... how should I say this? "A high end company." The though of running DMX through regular phone cord, which is not a twisted pair, is asking for trouble. In addition to the lack of shielding, the non twisting pairs, and the random line impedance, XLR connectors are designed to engage pin #1 first, thus draining any static charge before engaging the data pins, RJs are not. I sure hope their comparator circuits are static protected.
Lighting DMX control should never be run through the audio snake IMHO, as it introduces all sorts of bad scenarios. Stage boxes often common or case ground pin one, thus making an electrical tie between the lighting and sound companies. Even when this is not the case, there is a great surface area exposed from one foil shield to another, so even if you have electrical isolation, you have a capacitive cupping between the two.
Now, on to Times Square: I am sure they are a lot better of a company then when I did business with them back in the 80s. Back than, they were not known as er... how should I say this? "A high end company." The though of running DMX through regular phone cord, which is not a twisted pair, is asking for trouble. In addition to the lack of shielding, the non twisting pairs, and the random line impedance, XLR connectors are designed to engage pin #1 first, thus draining any static charge before engaging the data pins, RJs are not. I sure hope their comparator circuits are static protected.
It appears to me as though Times Square has decided to compete with the BakPak dimmer, and will most likely be successful, depending on components inside. Certain people have had issues with the IGBT technology, so an alternative may be just what certain markets are clamoring for. The Times Square DM1200 does have 5pin in and out, so just ignore the RJ14s and it should be a fine product. pie4weebl buy some of these and let us know how they work for you.
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Sorry: typo, it's "IGBT" and I have corrected my post. I know of one problematic installation from 1998, (was that really 10 years ago?), but I suspect it was due to the drive electronics rather than the technology and shouldn't have worded my post the way I did. On the other hand, the fact that neither ETC nor Strand have adopted the technology may reveal some of its shortcomings. The future of stage lighting dimmers is sine-wave, I suspect.
Derek are you mixing your technologies? IGBT can be used in "Sine Wave " dimmers with both Strand and ETC having "Sine Wave" dimmers.
Are you refering to "Reverse Phase " dimmers as these used IGBT's as the power controlling element but in a different way to the "Sine Wave " dimmers?
For those reading this who don't understand the terms, here are a couple of links from ETC that may help.
http://www.silentdimming.com/tech_reversephase.asp
http://www.silentdimming.com/tech_forwardphase.asp
I have also thrown in their link on Sine Wave dimming.
http://www.silentdimming.com/tech_sinewave.asp
Are you refering to "Reverse Phase " dimmers as these used IGBT's as the power controlling element but in a different way to the "Sine Wave " dimmers?
For those reading this who don't understand the terms, here are a couple of links from ETC that may help.
http://www.silentdimming.com/tech_reversephase.asp
http://www.silentdimming.com/tech_forwardphase.asp
I have also thrown in their link on Sine Wave dimming.
http://www.silentdimming.com/tech_sinewave.asp
JD
Well-Known Member
Not sure if I agree with the article saying there are no harmonic currents. After all, when you square off a sign wave, you have added a square component, doesn't matter if it's on the leading or trailing edge. Oh well, time will tell.
I would agree that reverse phase dimmers would by nature be quiet.
Now, here's a quick list of dimmer types, pro's and cons:
Standard Dimmer: Chops off the leading edge of the waveform.
Pros: Inexpensive, good workhorse.
Cons: Heavy due to large chokes, produces tons of noise.
Reverse Phase Dimmers: Chops off trailing edge of the waveform.
Pros: Much quieter, no need for heavy choke.
Cons: Newer technology so more expensive, lifespan yet to be determined.
Sine Wave Dimmers*: No chopping, varies amplitude of output. (think autotransformer-like)
Pros: Cadillac of dimmers. No noise. Probably increases lamp lifespan due to less filament vibration.
Cons: Creates more heat, Very expensive.
* I should add a bit about how Sine Wave Dimmers work- Pulse Width Modulation (PWM) is how a lot of switching power supplies work. The bulk of the waveform is sliced into small segments. Each segment is varied in width so that at full width, the full waveform is present. At a smaller width, only a small spike is getting through. To "heal" the waveform and make it a sine wave, the output is run through a choke. The choke stores the pulse as magnetism and then releases it back as current. If the pulse was 100 volts, and had a width of 50%, the output voltage from the choke side would be 50 volts. Regular dimmers use big chokes to help moderate the chop in their waveform and smooth it out, but they do this at 60cps, which requires a big chunk of copper and metal as the magnetic storage time is longer. Sine dimmers do it a 40,000 to 50,000cps. Because the frequency is so high, the choke can be very small as the storage time is very short.
One last note: Heat. Transistors, Triacs, and SCRs, all are somewhat the same in core design, the difference is that Triacs and SCRs are designed to have a runaway cascade so they go to full conduction when triggered. Transistors, don't. (Or shouldn't, although if you have worked in an amp repair shop, you have seen a few that did
) So, when fully gated, both will produce about 1 watt of heat for every amp of current passed. Trouble is, the highest heat is generated in the "in-between" state. (why audio amps put out so much heat.) There is a time between when a transistor is told to turn on, and when it actually does. This is know as the "slew" rate. (see Slew induced distortion on audio amps) At 60cps, you are entering the slew state 120 times per second. On a PWM operating at 50khz, you are entering the slew state 50,000 times per second. The result is you are in the slew state 416 times longer, so the device runs hotter. That being said, it is probably well offset in sine dimmers because standard dimmers require there to be quite a length of copper wire on the choke, so the resistance in this wire also throws heat.
I would agree that reverse phase dimmers would by nature be quiet.
Now, here's a quick list of dimmer types, pro's and cons:
Standard Dimmer: Chops off the leading edge of the waveform.
Pros: Inexpensive, good workhorse.
Cons: Heavy due to large chokes, produces tons of noise.
Reverse Phase Dimmers: Chops off trailing edge of the waveform.
Pros: Much quieter, no need for heavy choke.
Cons: Newer technology so more expensive, lifespan yet to be determined.
Sine Wave Dimmers*: No chopping, varies amplitude of output. (think autotransformer-like)
Pros: Cadillac of dimmers. No noise. Probably increases lamp lifespan due to less filament vibration.
Cons: Creates more heat, Very expensive.
* I should add a bit about how Sine Wave Dimmers work- Pulse Width Modulation (PWM) is how a lot of switching power supplies work. The bulk of the waveform is sliced into small segments. Each segment is varied in width so that at full width, the full waveform is present. At a smaller width, only a small spike is getting through. To "heal" the waveform and make it a sine wave, the output is run through a choke. The choke stores the pulse as magnetism and then releases it back as current. If the pulse was 100 volts, and had a width of 50%, the output voltage from the choke side would be 50 volts. Regular dimmers use big chokes to help moderate the chop in their waveform and smooth it out, but they do this at 60cps, which requires a big chunk of copper and metal as the magnetic storage time is longer. Sine dimmers do it a 40,000 to 50,000cps. Because the frequency is so high, the choke can be very small as the storage time is very short.
One last note: Heat. Transistors, Triacs, and SCRs, all are somewhat the same in core design, the difference is that Triacs and SCRs are designed to have a runaway cascade so they go to full conduction when triggered. Transistors, don't. (Or shouldn't, although if you have worked in an amp repair shop, you have seen a few that did
) So, when fully gated, both will produce about 1 watt of heat for every amp of current passed. Trouble is, the highest heat is generated in the "in-between" state. (why audio amps put out so much heat.) There is a time between when a transistor is told to turn on, and when it actually does. This is know as the "slew" rate. (see Slew induced distortion on audio amps) At 60cps, you are entering the slew state 120 times per second. On a PWM operating at 50khz, you are entering the slew state 50,000 times per second. The result is you are in the slew state 416 times longer, so the device runs hotter. That being said, it is probably well offset in sine dimmers because standard dimmers require there to be quite a length of copper wire on the choke, so the resistance in this wire also throws heat.Attachments
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