8mm Forum: Eiki 600 Ohm Output

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Topic: Eiki 600 Ohm Output

Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted March 16, 2015 04:07 AM

This posting is for owners of Eiki/Elf projectors in the SNT/ENT range who want to connect their projector to an amplifier for additional output.

You need a stereo 1/4 inch jack plug, the one with three contacts.

Referring to the tip as contact 1, the small second ring as contact 2, and the long section up the cover as contact 3, connect a screened lead to contacts 2 and 3, (the screening is to go on contact 3.)

Insert plug into the usual speaker outlet socket on the projector.

I have gleaned this from the Instruction Book but I must admit that I have not tried it.

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Maurice

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 17, 2015 06:44 PM

This is a balanced monaural output. It's a lot more common among professional audio equipment than consumer stuff.

The nice thing about this connection is that it removes the signal from chassis ground and makes it much easier to not get ground loops (and their nasty buzzing hum) and noise pickup when you connect up to an external amplifier. The catch is it works best when you connect up to a balanced monaural input.

When I make a cable for one of these connections I pick the end that's best grounded and connect the screen at that end and not the other. That way the screen won't wind up with ground currents flowing through it.

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 17, 2015 07:37 PM

Steve, is what you are describing typically a balanced XLR connection?

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"C'mon Baggy..Get with the beat"

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 17, 2015 07:54 PM

I think the connection is the same, what's different is the connect-or.

This way of connecting up can get nasty! I have a mixer panel that has stereo inputs like these:

Your usual nice, docile single three conductor stereo cable has now become two independent three conductor cables (R&L): yours to confuse between channels and contribute to the spiderweb.

-does work nicely, though.

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All I ask is a wide screen and a projector to light her by...

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Paul Mason
Jedi Master Film Handler

Posts: 540
From: Aldershot, Hampshire, UK
Registered: Nov 2013

posted March 18, 2015 05:26 AM

Maurice,
That's interesting. Do the Eiki instructions say whether you need to attenuate the speaker socket output with resistors to avoid overloading the amp?

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Paul.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 18, 2015 07:57 AM

I have a feeling these are actually two separate outputs: 600 Ohms sounds fine for a line level output (ELMO likes this value, for example.), but if you tried to drive a 4, 8 or 16 ohm speaker through this much resistance you'd be lucky to get even a whisper out of it!

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All I ask is a wide screen and a projector to light her by...

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted March 18, 2015 07:57 AM

It doesn't appear that any other connections need to be made. I quote from the Instruction Book:-

"For additional sound reinforcement the projector may also be connected to an external amplifier via the low level auxiliary line output.
The 600 ohm (unbalanced) line is available at the speaker jack when using a 3 conductor (stereo type) 1/4" phone plug wired as shown."

For 8 ohm output, contacts 1 and 2 are used, i.e., the two small end connections.

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Maurice

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 18, 2015 08:00 AM

So, they've configured it to do a line output or speaker output through the same jack depending on how you hook up the plug.

-that's interesting.

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All I ask is a wide screen and a projector to light her by...

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Paul Mason
Jedi Master Film Handler

Posts: 540
From: Aldershot, Hampshire, UK
Registered: Nov 2013

posted March 18, 2015 08:04 AM

Thanks Maurice for the useful tip. It very much assumes the projectionist is an audio-visual technician able to do simple soldering. My soldering is unreliable but many members will have no problem.

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Paul.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 18, 2015 08:35 AM

They aren't very common, but there are 1/4" plugs with screw terminals.

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All I ask is a wide screen and a projector to light her by...

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Steven J Kirk
Jedi Master Film Handler

Posts: 873
From: Southern England
Registered: Apr 2008

posted April 05, 2015 09:47 PM

There are of course adapters made to take a speaker output and convert to line-level. I have one made by BOSS, who make car audio stuff. Works great and the quality is great. It comes with RCA plugs and free-hanging wire. It is two channel so I just wired both into a mono jack plug. I then have two mono channels to go into a hi-fi stereo amp.

http://caraudiosecurity.com/b65n-speaker-to-rca-adaptor-with-adjustment

In fact I have two. One wired to a mono jack and one wired for stereo spade and pin DIN speakers. This I use for the Beaulieu 708 machine.

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VistaVision
Motion Picture High-Fidelity

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