1 channel dimmers

[Crash_Override]

Has anybody used those 1 channel dimmers that thomann.de sells? Which are good ones?

I would like them do be at least 10A. And have no flickering issues on lower intensities.

[kgallen]

The "original" Strand DIM-1s are good:

 

http://www.seleconli...roduct_id=10379

 

I've used them for conventional tungsten (Source 4's, Preludes and the like) and in switch mode for 4' UV tubes.

 

 

The Thomann ones look pretty much the same (although have 3-pin XLR), if these are the ones you mean:

 

http://www.thomann.d..._1ch_dimmer.htm

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

[Crash_Override]

Yes, I ment those.

There is 10A version of the Botex also there.

[the kid]

Never had any issues with the ones we have + ones I have used before and they were treated pretty badly and got quite a lot of dirt in them.

[Crash_Override]

Never had any issues with the ones we have + ones I have used before and they were treated pretty badly and got quite a lot of dirt in them.

 

Whats make and model of your dimmers?

[GreatBigHippy]

I would be interested in knowing if anyone has any experience using these with LED fixtures. I need to find something that'll work with source4 mini LEDs for a non-theatre job.

[timsabre]

I haven't used those ones specifically but I have been involved in a few jobs with "mains dimmable" leds and my experience is that triac dimmers don't work unless you put a big load lamp on as well (500W). If you don't, the capacitance in the drivers causes the dimmer to latch on at full or flicker a lot.

 

Reverse phase (IGBT) dimmers work much better but are hard to find in a professional form. Sinewave IGBT doesn't work well because the driver relies on timing the switchoff point to determine the setting of the dimmer - you get a bit of dimming but only in the 70%-100% range.

 

With a reverse phase dimmer (depending on how the LED driver works) you can dim down to about 10%, but you can never dim them up from off - they always snap on at about 40%.

Also most of the dimming seems to be in the 40%-60% region of the dimmer.

 

Basically mains dimmable LEDs are not very good, avoid and use ones with a 0-10V or DMX control input if at all possible. I'm surprised the S4 mini LED doesn't have that option but it doesn't seem to.

[xylophone]

Very timely post this...

 

 

 

 

I have been watching but not joined until now.

 

I have a couple of old Strand lamps and wanted to control them.

 

I had toyed with the idea of a DIM1, but as other posters note, there are a couple of suspiciously similar items available from various suppliers (like CPC et al) , but the Strand one has the advantage of a BS546 socket and a wired remote fader, whereas some others don't.

 

I called up a Strand dealer in Bristol, and they told me that the units are all made in China.

 

Time meant I bought a Transcension UP-2 from CPC, also made in China. (It has 3 pin XLRs for DMX, and an onboard fader) but 90% looks the same as the DIM1

 

My observations about this unit are as follows, and if anyone can provide a comparison with (say) the DIM1 I'd be interested.

 

Setup:

 

1 x 500W load (profile lantern)

 

1 x UP-2 unit

 

Observations:

 

1. The dimmer law is very non linear from a perception perspective - the light comes on too early and is at perceived 50% brightness by about 20/100 and 95% brightness by about 65/100 on the unit fader. (I've not had a chance to try it with a DMX controller so I don't know what that behaviour might be)

 

2. 1% shift on the fader represents a noticeably flicker=step in output brightness on the lantern on mid range values, clearly something to do with the analogue > DMX > analogue converter electronics which provides the "last takes precedence" functionality.

 

3. Electronics - basic linear circuit (I think) feed-forward phase angle switching of a ~25A triac device, (no output power feedback)

 

I concede that the device was only advertised as "suitable for a follow spot", which typically isn't an integral part of a scene change, but it's somewhat disappointing really.

 

I was wondering if somehow the Strand one has a better piece of software in it to provide a more linear looking brightness profile (S Law or whatever). It's a shame, because clearly this device could work a whole lot better with some decent software....