Audio Out for Eumig 824 Sonomatic

[Steve Klare]

Hi Ethan,

Most S8 sound projectors can't access the balance stripe, the Eumig 800s are included here. Most films aren't stereo, so this usually works out just fine.

As I remember it, I found a cable terminated with the 5 pin DIN that had wires running to all the pins, then I used an ohmeter to pick and choose the wires to pins 2 and 3. I just soldered these into the tip(3) and ring(2) terminals (balanced connection) on the 1/4"plug and then crimped the ears down on the end of the insulation to provide strain relief.

I'm seeing DIN cables with two bare wires on the far end, but so far they all run to the wrong pins!

It's also possible to do it the other way: find a cable terminated with 1/4" plug and solder the stripped ends into the terminals on the DIN. I've found these require a steady hand and a fine soldering tip! I've also had connectors like this melt a little so the pins fall out of alignment, so you need to be quick.

What kind of terminals would you like to plug into? I use a phone jack because I plug into a mixer, but that doesn't apply to everyone.

[Brian Fretwell]

My Akai D4000stereo tape deck came with a DIN to 4 RCA plug lead. I have used that it is easy to swap plugs until you get the signal you need.

[Ethan Knightchilde]

Hi Ethan,

Most S8 sound projectors can't access the balance stripe, the Eumig 800s are included here. Most films aren't stereo, so this usually works out just fine.

As I remember it, I found a cable terminated with the 5 pin DIN that had wires running to all the pins, then I used an ohmeter to pick and choose the wires to pins 2 and 3. I just soldered these into the tip(3) and ring(2) terminals (balanced connection) on the 1/4"plug and then crimped the ears down on the end of the insulation to provide strain relief.

I'm seeing DIN cables with two bare wires on the far end, but so far they all run to the wrong pins!

It's also possible to do it the other way: find a cable terminated with 1/4" plug and solder the stripped ends into the terminals on the DIN. I've found these require a steady hand and a fine soldering tip! I've also had connectors like this melt a little so the pins fall out of alignment, so you need to be quick.

What kind of terminals would you like to plug into? I use a phone jack because I plug into a mixer, but that doesn't apply to everyone.

A 1/4” headphone connection would work fine for me. (It will go into a mixer.)

I am not in front of the projector at the moment, but I recall that the 824 Sonomatic has a switch with positions for playback of stripe 1, 2, or both. Seems very strange that the audio out only sends a mono signal (according to Joerg’s post it would be terminal 3) unless it’s a mix down which would make better sense.

[Ethan Knightchilde]

My Akai D4000stereo tape deck came with a DIN to 4 RCA plug lead. I have used that it is easy to swap plugs until you get the signal you need.

4RCA? So there are four single
channel audio outputs and you just find which ones have your l and r channels?

[Janice Glesser]

To connect my Eumig 824 to my sound system, I use this type of plug. I have a balanced plug on the other end of the cable, however you can use any other type of plug that works with your sound system.

[Steve Klare]

Eumig 824 IS twin track!

Interesting!

Does anybody have the manual for this one? It would be great if it did two channel line out.

[Ethan Knightchilde]

Eumig 824 IS twin track!

Interesting!

Does anybody have the manual for this one? It would be great if it did two channel line out.

I have the manuals for it but the line out info is almost non-existent. There is the spec line in my original post, and then there is a reference in the manual that says “see the wiring diagram” (which you need a microscope and an electrical engineering degree to read and understand). I’d be happy to scan it if it will help this or a future discussion.

[Steve Klare]

I don't have a microscope, but I do have an electrical engineering degree! (Taxidermy school was all filled up!😉)

I'd love to see a scan!

[Ethan Knightchilde]

I don't have a microscope, but I do have an electrical engineering degree! (Taxidermy school was all filled up!😉)

I'd love to see a scan!

I’ll try to get at least the wiring diagram scanned tomorrow!

[Brian Fretwell]

4RCA? So there are four single
channel audio outputs and you just find which ones have your l and r channels?

2 input, 2 output from that tape deck, which had off tape monitoring.

[Rob Young]

Just to throw this in here regarding my Beaulieu (I have no idea about the Eumig) but I did exactly what Brian did and bought a DIN to 4 phono plugs lead and simply tried each until I found the 1 with output.

I saw 1, because, although the Beaulieu (circa 1979) is a twin track machine, the output is mixed into a single mono output regardless of whether each or both tracks are selected on the machine. I gather that later versions (certainly the STEREO version did have 2 separate outputs). My Elmo ST1200HD certainly does.

So I would hope the Eumig will output 2 separate outputs for each track, but not necessarily so.

[Ethan Knightchilde]

I don't have a microscope, but I do have an electrical engineering degree! (Taxidermy school was all filled up!😉)

I'd love to see a scan!

Here it is! I suspect that this will be the same situation as Rob’s Beaulieu with a single mono output.

[Steve Klare]

Thanks for the scan Ethan!,

Let's zoom in to where I think the business end of this line level stuff is happening: (Schematics are actually interpreted, not read.)
.

That Eastward pointing triangle up in the NorthWest is an operational amplifier. I believe this to be the pre-amp that boosts the signal from the heads and feeds it to the main power-amplifier. If this was a true twin-track machine I would expect there to be two of these for two independent signals, yet there is only one. The circle down in the SouthEast I believe to be the 5 pin DIN. It has only two connections, one of which is chassis, and the other to be signal (which ultimately connects to that same pre-amp in the big picture). I would expect this to have two signal connections: one for each track.

I can't read the pin numbering: please check? Pin 3 should be at 12 O'Clock and pin 2 at 9 O'Clock.

I'm not so sure this should be interpreted as the end-all of this. It's even possible whoever composed the 824 manual used a single track schematic because they didn't know the difference and after they printed and shipped a couple of thousand copies, even if someone noticed, they just shrugged and said "Whatever!".

(I do a lot of technical document work: what can go wrong, WILL!)

The ultimate test would be to stick an ohmmeter in pin 5 and measure something between 50,000 and 100,000 Ohms to chassis. If it's open circuit then no balance stripe signal will be available at that pin.

[Ethan Knightchilde]

Well, I found a multimeter I kept with my 16mm rig to check my batteries on the road. However, I’m probably doing it incorrectly because I can’t get a reading.

I think you’re right about the “whatever” approach someone took with that wiring diagram.

On a closer inspection of the DIN plug, it seems that there are 3 terminals that have connections. It’s a little difficult for I see. I’m assuming that they are numbers 1, 2, and 3 based on the diagram used for the recording side. 4 and 5 appear empty in the photo by comparison.

Might that be indicative of 2 channel output?

[Steve Klare]

It's possible: let's see how they ohm-out to ground at your end.

The pin in the diagram at the 9' O'clock position is chassis ground. Since the signal is measured referenced to chassis, there should be only one signal.

For some reason the one at the 6 O'clock position has no connections and they show it (JUST it) anyway. I'd rather it showed something more like "1,4,5 N/U". -but, Hey! I was about 12 when this was drawn, so I wasn't at work that day!

EDIT: An analog meter has a battery for the Ohmmeter part: If you aren't getting a reading you need to replace the battery. A digital meter has a battery for ALL the readings, so if you are even getting a display, your battery is at least trying!

The test for any Ohmmeter is short he probes together, and the display (digital or analog) should swing to very, very close to zero. Separate the probes and then the display should swing up to infinity. Very commonly on a digital meter you will see something like "OL".