Right.

At present, all my lights on the truss are fed into 2 extension cables (3 lights per cable). I am going to invest some cash in the PC-08 Switcher from Prolight. I will also need to convert my lights to male IEC plugs. To do this I will make up entension cables for each of the lights because I don't want them to be terminated with IEC plugs. I will invest in some black cable an single trailing plug sockets for this. Comes to approx £90!!!! But is worth it.

So,

DISCO LIGHT - SINGLE TRAILING PLUG SOCKET (end of cable)- IEC (on other end of cable) - SWITCH



Good, bad?

£90.

Make your own, buy a 50m reel of three core and x amount of IEC sockets/plugs, should get change from £50

Just a word of warning, I had the same idea, and purchased the very same type of unit.

no matter what I tried or how it was wired, I always got loud pops through the speakers, caused by the switch when turning on and off !!!!!
I did some research and with advice from here, I was told the reason for the popping is because you are switching the whole load all the time.

I have since paid a little more and got a switching box that does the same without the pops !!! I think its called "zero switching" or something like that.

hope this helps as I was cheesed off when I had paid out my dosh and all I got was loud pops through my speakers.

The pops are the transformer thingeys (techie term) turning on and off, pay a little more, you get what you pay for, CP has some great priced one in a few weeks ago when I spoke to him, he'll come along soon hopefully..................

Many cheap switchers don't have any suppression and switch the mains power directly, resulting in spikes travelling back down the mains lead or via RF to nearby electrical equipment (Your Amp, Mixer, Cd Player, Laptop, Radio mic reciever etc) and being amplified several times resulting in loud pops through the PA.

This is similar to the loud click you get through an AM radio when you turn on a light at home.

These problems can not only be a nuisance, but in some cases repeated use can cause premature lamp failure (Bulbs blowing) and hasten the wear of motors and other sensitive components within the effect. The interference is cause by arc-ing of the contacts inside the switch or relay when the metal contacts are closed - the click being caused by the spark that is produced as the two metal contacts close the circuit. Occasionally, in rare circumstances, these surges can produce back EMF which in turn can blow the microprocessors in DMX effects - although this is rare, but I have come across it before in cheaper effects with no protection.

In short, if you must use switch panels then use the type which use low voltage logic circuits (called Zero Volt switching as Hoseman Ade mentioned) to switch the load. Instead of physical switches, triacs and solid state relays are used to switch the mains, instead of physical metal contacts. This is how a conventional 4 channel chaser works, using solid state devices rather than the problematic switches and coil driven relays.

This is the safest, less problematic and prefered method of switching effects, although the amount of switching should still be kept to a minimum since frequent switch on / off cycles can still shorten lamp life and coils in motors and transformers. Don't be surprised if you see a rise in lamp replacements if you use the switcher on a regular basis, after all when does lamp failure occur the most often??.......

When a Lamp is turned ON

Told you

So, Chris, do you have pricing for a zero voltage switching device?

Chris do you have any of the bulgin ones that you mentioned?

I don't know but wouldn't it be a bit neater using some form of multicore extension lead to feed into a compatible switch pack ?

Doesn;t the way you suggest mean you have say 5 (or how many lights you have) power leads running down the stand?

I have one unit which used to be used by me personally, its only been used a handful of times and is in 'as new' condition.

It is the four channel type using low voltage triac switching and has a single bulgin socket output.

Make me a serious offer for it.

I don't have any more of them, since the company - TTL ltd stopped trading some time ago, and the company who bought them no longer offer this item.

The thing is Chris I have 5 effects- would I be okay using a splitter lead to give me two iec plugs?

Is this rackable? Do you have a pic?

I would make you an offer but I don't have a clue how much these things retail for? If I knew I could make you a better/more reasonable/sensible offer.

Thanks
DD

So would this very unit have pops when turned on? It says to have protection and good grounding etc but......?

So, to end this topic, I would make my own but have some cash to spare...

I'm gonna get the NJD EURO 8S - zero switching.

Good anyone?

NJD zero switching , yep good bit of kit

if they still have the little screws in the touch areas make sure they are done up tight as for some odd reason they work lose and then it stops working....

Chris I have pmed you regarding the switch panel.

How does 50 pounds including postage sound?

Zero switching is switching the load as the mains voltage passes zero volts.
This is easily done with a small microcontroller and triacs.

When I had record decks I put 100nf caps across the switches and this virtually eliminated pops.
Not recommended unless you know what you are doing !

Nigel Electronics Design Engineer.

The best way to suppress mains switches is an RC network: ie a Resistor and Capacitor in series in the same package (or seperate if you want to make them yourself). This limits the peak currents when you turn the switch on again, since the capacitor will sometimes still be charged and the switch contacts will short it and cause another spike and pop.

If Zero switching units go through a triac, surely some electrical items will not work as well going through one (as opposed to a relay or switch with supressor wired across live+switch). I'm thinking things like switch-mode PSU's (?)

Correct me if I'm wrong, but the output from a triac won't be "true" 50hz wave (it will be chopped slightly at the 0v point due to the drop accross the internal triac "diodes" ?

I remember some time ago that some items (transformer based) had issues with a 3 channel sound to light controller.. Only wish I'd kept the unit.


David

But the output from a (good) triac switchpack is a 50Hz sine wave...the volt drop is negligible and doesnt affect the load. Most switch-mode power supplies dont care if they're on AC or DC because they only convert the AC to DC first anyhow by bridge rectifier.

Problems ocurred a few years ago switching transformer loads as triacs weren't as good as they are now. This is due to a characteristic called their DV/DT figure. Triacs needed 'snubbing' by large RC networks to 'knock off' the edges of the switch-off voltage waveform presented across the triac at turn-off. This caused some triacs to either fully or partially latch-on even if you'd turned them off, since the construction of a triac makes them susceptible to being triggered by steeply-curved voltage transients. Large inductances in the load could also cause the triac to prematurely commutate (switch off again) due to the skewed current and voltage waveforms though to be fair this caused certain lights to flicker rapidly rather than stick on. Cheap switch or dimmer packs often omitted the expensive RC networks and simply labelled their products as for 'resistive lamp loads' only.

Modern triacs have better tolerance to inductive loads and usually dont need RC networks to work reliably, though some designs have them for RFI interference reasons. Many circuits drive the triac by either 'hard firing' (supplying a pulse train of gate pulses to keep the triac on all the way through the cycle) or use zero-crossing optocouplers which contain a minature IC to fire the gate at the correct time.

Fitting the wrong type of triac for the drive circuit employed is another cause of incorrect triac operation in a switch or dimmer pack. For example a BTA08-600B and a BTA08-600BW are not the same device: one needs a snubber and the other doesnt!

One or two weird loads such as the Martin Robozap and the EVL Spin use their own internal triacs and/or IGBT switches, these generate waveforms that can cause certain switchpacks to misbehave, but they dont usually recommend using these on a switchpack anyway. If in doubt, use a suppressed rocker-switch panel for effects and a triac-based one for generics ie Parcans and Pinspots as 'Gadget' recommends.

wow!!!
that was way way over my head.
never understood a word.
rocket science or what.
very impressed though.
i might cut n paste that to another site somewhere lol.

Well, this was 3 and a half years ago and as must be my NJD 0 voltage switch and all its cables I made.

Was worth it..