Film-Tech Forum ARCHIVE: Component Engineering ASR-40

This is topic Component Engineering ASR-40 - Voltage? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Matt Close (Member # 996) on 01-02-2003, 11:16 PM:

I have aquired an ASR-40 LED reader with no instructions .... the PDF file in the manuals shows me the polarity for the main unit, but no voltage specs for either the main unit or the LED module.

Can someone who uses these units please tell me the correct voltage for the reader, and the correct voltage range for the LED module...... I'd hate to kill 'em [Wink]

Thanx

Posted by Steve Guttag (Member # 268) on 01-03-2003, 12:02 AM:

For any LED reader system...run the LED as low as possible and still achieve Dolby-Level. The lower you run em, the longer they will last.

Steve

Posted by Jean-Michel Grin (Member # 1360) on 01-03-2003, 03:16 AM:

I've experienced good results with a LS-30 (for digital and analogic). The current inside the LED was 137 mA for the analog reader and 225 mA for the digital reader.

Posted by Bill Purdy (Member # 202) on 01-03-2003, 01:14 PM:

Matt, Steve Guttag has given you the best answer. This is why we make our power supplies adjustable. The other answer to your question is that LEDs are current operated devices, not voltage. The voltage across the LED will be whatever it wants to be for the current you have set. As the LS-40 supply is current regulated it will hold that setting until you change it. The other outputs are for the pre-amps in the reader head and they are not at all critical because the operating voltage needs to be only a little higher than the signal voltage which is in the millivolt range.

Posted by Jim Alexander (Member # 226) on 01-03-2003, 03:05 PM:

As Bill and Steve both pointed out, the pot is set to give the lowest current for an active Dolby signal. I installed my ASR-40 this past summer and have been extremely pleased with it. The only mistake I made was the orientation of the reader when first installed. The instructions are not really clear about this, but the lettering needs to be out. I originally placed the lugs out and couldn't figure out why I couldn't get any signal at all... Well Duh! Of course the reader was not longer reading across the audio tracks but inline with them! Once I figured out my "mistake" it worked like a wonder. Very stable and the Auto shut off on the power supply is really hand and well worth the time and effort hooking it up to the projector power switch.
The only question I have, is with replacing the LED when the time comes...how much do these little devels cost and how hard are they to get?

Posted by Richard Fowler (Member # 893) on 01-03-2003, 04:00 PM:

The LED-V chip is a Dolby part and is available from all manufacturers of readers...you should expect long life on Component's hardware and upon ( slowly less output ) end of service life, should take 10 - 15 minutes to change out.

Posted by Matt Close (Member # 996) on 01-03-2003, 05:53 PM:

Thanks for your replys guys, but I am still in the dark as to voltage requirements. Can someone tell me exactly what I should feed in to each of the two units?
i.e. 5V, 12V, 24V? Regulated? Unregulated? .. and current requirements are only around a few hundred milliamps, yes?

Posted by Jim Alexander (Member # 226) on 01-03-2003, 06:08 PM:

The hookups are all labeled for Reader to Power Supply and Power Supply to LED. The LED is the only one that is questionable since the polarity of the LED is not for certain. Trial and error will get it lit (Not to worry since there is not enough current to blow the LED should it be reverse polarity). The Power wupply is 115/220 50/60Hz depending on the selection and your power grid. The only other lugs are on the power supply and they are strickly shorted for turning the power supply off or open for turning it on. The adjustment pot is for setting the current of the LED. If you are uncertain of yourself, you can turn this fully counter-clockwise to turn the current to its lowest while you are hooking up the unit, and then turn it up slowly until the LED lights up.

The following attachment is the Installation Manual for the ASR-40:

http://www.componentengineering.com/webdocs/asr40.pdf

Other than that, I'm not sure what you are looking for as far as voltages....

Posted by Jim Alexander (Member # 226) on 01-03-2003, 06:10 PM:

Ahhhh...did you not get the Power supply with the unit??? If not, the reader/Led are not much use since they are designed to work with a dedicated power supply that is normally sold with it.

Posted by Matt Close (Member # 996) on 01-03-2003, 06:31 PM:

I think they did not originally come with a dedicated power supply ... I think that is a recent addition by Component Engineering .... I could be wrong though.

Posted by Richard Fowler (Member # 893) on 01-03-2003, 06:50 PM:

You can purchase C.E. components by the piece or the system based on your requirements.

Posted by Jim Alexander (Member # 226) on 01-03-2003, 08:09 PM:

For the easiest application and installation, I would suggest you look into getting the power supply for it. The part number is LS-40 and lists for around $112.00 in the States. I have no idea what the cost would be down under...

Posted by Matt Close (Member # 996) on 01-05-2003, 04:00 AM:

.... bumping up ..... come on guys.... doesn't 'somebody' know what 'voltage' to feed these units?

Posted by Jean-Michel Grin (Member # 1360) on 01-05-2003, 10:13 AM:

Ok Matt,

A classical Red Led work for a voltage between 1.5 - 2 volts, but for theses Red Leds tha we use in a sound reader I never asked myself how munch it was.
The improtant thing is how munch current pass trought the Led, but for you tomorrow I will take out my multimeter an making the measurement.

See you !

Posted by Gordon McLeod (Member # 33) on 01-05-2003, 11:44 AM:

Matt why reinvent the wheel,
The LED is a current device and as such as has been said the voltage is irrelevent for all intents and purposes. The preamp is bipolar and I believe is =/-12vdc
But for the price buy the proper supply it has the proper regulation and termination for I have found that some readers didn't like the competitors powersupplies

Posted by Jean-Michel Grin (Member # 1360) on 01-06-2003, 02:16 AM:

Matt,

I had this morning checked the voltage for the Led atthe outpute of my LS-10 power supply (almost the same system as the ASR 40 but double unit are used for the analog and Digital Reader)
I've mesuread 1.07 volts; but remember, only the current passing trought the Led is important, so use an good multimeter to check this...

In hope to help you, and sorry for my weak english.