8mm Forum: Elmo GS-1200 audio output to stereo amplifier

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Posted by Doug Johnston (Member # 4747) on February 07, 2018, 03:21 PM:

I've owned an ST1200HD for awhile and really like that projector. Solid and reliable. I've just purchased a GS-1200 and am waiting for it to arrive. I can see from online articles that I can go from the projector's AUX-OUT (ports 1 and 2) using two 3.5mm jack cables to a stereo amplifier. I'm not an audiophile and so I'm wondering if the cables I need to purchase should each be single channel or two channel. Logic tells me each cable needs to be single channel. Thank you all in advance.

Posted by Steve Klare (Member # 12) on February 07, 2018, 03:25 PM:

These are two independent monaural connections: one per stereo channel. Either a mono (Tip,Sleeve) or a Stereo (Tip, Ring, Sleeve) 3.5mm plug will connect at the projector end. The difference is the GS's jacks have no third contact to connect to that middle "ring" connection, so it is just along for the ride.

I guess what you need are two separate 3.5mm mono plug to RCA male cables, or one two channel cable of this type for both R&L.

I've messed with one of these into an Amp: the twin track output is a lot stronger than the ST-1200HD's and the results were quite nice!

Posted by Doug Johnston (Member # 4747) on February 07, 2018, 04:21 PM:

Thank you very much Steve. I've followed your posts for several years now. Your explanations are always easy to understand and your advice is very much appreciated. Thank you Steve.

Posted by Steve Klare (Member # 12) on February 08, 2018, 09:55 AM:

Thanks!

These (-or ones like them) are what you are looking for:

3.5mm Mono to RCA

-now the trap I'm setting for us here is me assuming your Amp has RCA inputs: you'd better check my math before you buy anything! (My amp does...)

Good Amp inputs to use are things like "Tape", "CD", "Aux" or "Video" if you happen to have "Phono", it won't work. (it's too sensitive).

If you hook up everything and you get a low pitched buzz, you probably have a grounding problem. I had a huge problem at first because my projector grounds were fighting with my cable tV company's! (There's things that can be done about it...)

Posted by Graham Ritchie (Member # 559) on February 08, 2018, 02:05 PM:

What some folk also do myself included, is to connect your external amp to the rear monitor sockets of the GS1200. This still gives you control of the volume, treble and bass from the projector controls. You simply set the required volume on the external amp then leave it, and do everything else with the projector itself. Also if you are running a stereo track, you can balance the tracks, still using the projector itself with its left and right volume controls etc and using the level meters to balance the output feeding the external amp for both channels.

With the GS1200 you have a choice of using either the Aux Out which is a fixed output and levels controled by your external amp, or using the Monitor Out... [Smile]

Posted by Steve Klare (Member # 12) on February 08, 2018, 03:28 PM:

How True!,

I brought my sound system to CineSea a few years ago and plugged into Doug's GS at the Auxes. In my system the Amp isn't ever near the projector, and that time wound up behind the screen with the speakers (such were the cables I brought with me...).

-every time we needed to change the volume I had to ran the length of the throw and dive behind the screen to adjust the volume at the Amp. I put a lot of mileage on my shoes that night!

These days with fixed Auxes on a projector I control the volume with a mixer by the machine(s): showing films shouldn't be so...athletic!

-sometimes you have to suffer a little before you figure things like this out.

Posted by Graham Ritchie (Member # 559) on February 08, 2018, 05:45 PM:

Steve

I came across the idea of using the monitor out after watching a video. I think it was one of one of Keith Wilton conventions. I thought then [Roll Eyes]

why are they using that, instead of the aux out. Thinking if the experts can do it I must try it out myself...so I did [Smile]

Posted by Paul Adsett (Member # 25) on February 08, 2018, 06:41 PM:

You can use this system on any projector with a headphone socket, such as the Eumig 900 series. I agree that it is a good way to go, particularly if you are sitting with the projector. One caution though is to keep the projector volume control settings pretty low, so as not to overload your external setero amplifier, as the headphone output level is much higher than the AUX output level.

Posted by Chip Gelmini (Member # 44) on February 10, 2018, 10:33 AM:

I have been using a GS 1200 machine since 2014 and I will never use anything else. This is a workhorse and a remarkable machine. To buy one on Ebay is easy yet frustrating as it will need repairs. But after all of that, comes joy because it is a true beauty. Take it from one who has been through this several times with no regrets.

I run mine only with the bulb it was designed for. I have no need to change the lamp house method or design. I do not need brighter or longer lasting lamps.

One thing I have done that is different, is to use the external speaker output as a “secondary auxiliary output.” For those of you familiar with the ST 1200 aux out, this works the same way. That is, the volume control is brought up to send the sound to an external receiver.

To do this, you will need two plugs called 2pin-din. A link is provided below as a good source for this plug although you will receive just the plug and will have to open it up and install a cable to it which is easily done.

I have also run both sets of outputs (2 pin din AND aux out) in to a small switch box. The output of the switchbox goes to the receiver. In this method I avoid swapping cables. All I have to do is push a button and projector outputs are easily changed.

The advantage is to fill a 1200 foot reel with two cartoons and three trailers spliced to the head of the first feature movie reel. For example mono shorts on the front of a stereo feature. One button changes the sound.

Another good example: Magnetic shorts on the front of an optical feature. In this projection step you would begin with magnetic sound, then switch to stereo and switch from mag to optical then switch back to mono. The extra step mutes the POP sound when changing between the sound formats.

Many of these tiny switchboxes have multiple inputs that are numbered. So I put the 2 pin din output in switch one; stereo in switch two; and use switch three (silence) for the mute mode.

And by filling the reel, to one hour run time, you maximize efficiency of the projector and lamp life of the bulb.

The volume knob with 2 pin din goes no higher than 2 for magnetic, and no higher than 3 for optical. Theater sound is adjusted with the receiver volume control, not the projector. In this mode, your Elmo GS 1200 is like a theater projector – the sound output is preset by a technician – and the projectionist adjusts the sound at the Dolby unit.

It should also be noted that to avoid an over modulated soundtrack in optical prints, Elmo put a resistor on the optical mode output. It is only natural and very safe to turn it up more than magnetic, so don’t worry about having to do it. Stay within number 2 (the printed scale around the volume knob) for magnetic – and number 3 for optical.

When finally connected – run everything mono through 2 pin din. And everything stereo through aux out. Assuming you have a good sound system for your theater and that it is calibrated properly according to the amplifier’s owner manual, you should be quite impressed with the results.

After reading several posts in this thread, I would use caution when using the headphone outputs on the GS 1200. It should really only be used for the headphones as it has a higher output and can cause feedback or distortion if fed to a secondary receiver then to receiver speaker boxes. On my machines, the headphone output is left empty and is never used.

2 pin plug purchase link:

https://vetco.net/products/2-pin-din-male-inline-plug/ve-ca075?gclid=EAIaIQobChMIz-3lhN-b2QIVDzJpCh1-wggOEAQYASABEgJIZPD_BwE
Happy film presentations

Chip Gelmini

Posted by Doug Johnston (Member # 4747) on February 13, 2018, 10:18 AM:

Thank you Steve and everyone. Very much appreciated advice. I will try both GS-1200 audio options. I'm still waiting for my Heathkit SA-2 amplifier. I'll be plugging the amplifier into two Frasier Concerto speakers. Amp is 15W per channel and speakers are 25W. Nearing retirement, I'm very new to much of what I'm doing here but am excited and inspired by your expertise and obvious passion with this. I'll share photos and document the steps and obstacles I ran into. Many thanks again!!

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