Audio Out for Eumig 824 Sonomatic

[Ethan Knightchilde]

Next stage! For someone who has never done this before, what you would recommend in terms of materials? Should I find a cable of suitable length with a mono 1/4” jack, cut the cord at one end, and solder onto a 5 pin DIN?

[Steve Klare]

I'm with Ken here: soldering into a 5 pin DIN can get difficult. I think the easy way would be to buy a 5 pin DIN to 5 pin DIN cable twice as long as you want and cut in in half (-lengthwise!). This cable will have every pin wired, so you should use your new Ohmmeter Skills to find the bare wires to pins 3 and 2.

Soldering onto a 1/4" phono plug is much easier. (-just don't forget to slide the cover over the cable first!)

The question then is what is your mixer expecting (-and YOU thought you were done with all this!😉)

If the mixer is expecting a balanced signal, solder the wire for pin 3 to the tip terminal and the wire for pin 2 to the ring terminal.

If the mixer is expecting an unbalanced signal, solder the wire for pin 3 to the tip terminal and the wire for pin 2 to the sleeve terminal.

(Given the grounding situation with the average Eumig projector, "balanced" is the way to go.)

Oh! -and when you are done, coil up the unused cable-half and throw it in the drawer (You never know...)

[Ethan Knightchilde]

Good times. For the cable, are DMX and MIDI anything special or doesn’t it matter as long as it’s 5 pin male to male?

[Steve Klare]

I guess if it's shielded cable that in of itself should be good enough. Our kind of audio isn't that demanding.

What kind of mixer do you have?

[Ethan Knightchilde]

I guess if it's shielded cable that in of itself should be good enough. Our kind of audio isn't that demanding.

What kind of mixer do you have?

Samson MDR 624. I’ll use the mono line in channel 2 for this. (Channel 1 will be from
the Elmo 16CL and channels 3/4 will be from the Elmo ST1200 HD.)

The mixer plugs into a Yamaha Receiver RX-V677.

[Steve Klare]

OK, you've got your balanced input, which is good. On my mixer (Behringer Xenyx 802), the lines are configurable unbalanced or balanced (all depending on the use of a TS or TRS phono plug). Beyond the balanced inputs' benefit of canceling out ground loops, it also doubles the input impedance from 10 kOhms to 20 kOhms, this also eases the reduction of input voltage level I was talking about a few pages ago because of the Eumig's 50,000 Ohm output impedance.

I hope yours does the same.

One of the nice things about using a mixer, is it deals with all this kind of connection nonsense in isolation from the input to the amplifier. Once you have that part in good order it's always the same.

Janice's idea of using the speaker output to drive a line level input has the merit of very low impedance, but scares me a little because the voltage available can be too high for line level. When I wanted to plug in my Kodak Pageant, I had no choice but to go this way, so I put a voltage divider in between:

Getting Line Level Audio from a Kodak Pageant

[Ethan Knightchilde]

Not to muddy the waters but…

I was looking through my box of legacy cables and connections to see if I could find anything usable before buying more and I found this.

For my intended purpose of connecting to a mixer and then the receiver, would splicing this to a cable with a 1/4” mojo jack for output through the speaker jack work equally well? (Janice had shown this in an earlier post.)

Another question—regardless of which option I should got with, what should I look for that will “wrap” the area of the cable where the soldering is done?

(Sorry for all this. Thought I DID preface this entire thread by saying I am unfamiliar with such topics.)

[Steve Klare]

Ethan,

What you have there is a DIN 2 pin loudspeaker connection. It's what Janice was talking about in post #20, and what I referred back to in post #51. It is a usable signal for this with the caution it is meant to drive a speaker and depending on the volume setting, the voltage could be high enough to damage a line level input. There are commercially available devices to reduce the voltage and prevent this, but I built my own (-because I like to build things!).

There is a standard polarity here. I'll do a little ohmmeter work later and be sure what it is before I say so.

The cover that comes with the 1/4" phono plug covers all that needs covering.

(I'm kind of curious what that Eumig spec. sheet says underneath your connector!)

[Ethan Knightchilde]

Ethan,

What you have there is a DIN 2 pin loudspeaker connection. It's what Janice was talking about in post #20, and what I referred back to in post #51. It is a usable signal for this with the caution it is meant to drive a speaker and depending on the volume setting, the voltage could be high enough to damage a line level input. There are commercially available devices to reduce the voltage and prevent this, but I built my own (-because I like to build things!).

There is a standard polarity here. I'll do a little ohmmeter work later and be sure what it is before I say so.

The cover that comes with the 1/4" phono plug covers all that needs covering.

(I'm kind of curious what that Eumig spec. sheet says underneath your connector!)

Gotcha. OK then I’ll look for a DIN to DIN cable and a phono plug as planned. Here are the spec pages.

[Ethan Knightchilde]

Do you think these will work ok?

https://a.co/d/3TLrqcu

https://a.co/d/cD3BFuq

[Steve Klare]

Ethan,

I'd say you need to look into the instructions for your mixer and find out what it takes to produce a balanced connection. On my mixer you need a TRS (Tip-Ring-Sleeve) plug with Eumig's pin 2 connected to the ring. The plugs you show are 1/4" TS (Tip, Sleeve), which would only be able to provide an unbalanced connection on my mixer (Eumig Pin 2 connected to the sleeve).

Does this have to apply to your mixer too? -not in the least! That's why you need to do research here. (You may even find these inputs are always balanced and the choice of TRS or TS is unimportant!)

I don't think an imbalanced connection is the way to go if it is a choice. Eumig 800s often have grounding issues and connecting imbalanced can give you a ground loop.

How this manifests itself is something like this: Have you ever stood next to a speaker, for example a public address system, and heard a low, buzzy tone always coming out? That's what we are trying to avoid here.

The first time I hooked a projector into an Amp, I had this and it sent me back to the internal speaker for a couple of years it was so nasty!

(The DIN cable looks fine! At least that part was simple!)

[Ethan Knightchilde]

The mixer says that the mono input channel is electronically balanced. That aside, I haven’t found a single balanced mono 1/4” plug. They’re all stereo!

If I get a stereo plug like the one below, is it going to affect my ability to pan or will there be any annoying jiggling with the plug in the mixer's jack, etc? (It seems I've run into those both before at some point.)

https://a.co/d/24O3mQt

[Steve Klare]

OK, does your manual describe the 1/4" plug you need to use as something like "TRS" or "TS"?

This is where it can start to get just a little bit weird! With my mixer, a balanced monaural input requires what you (and most everyone) call a "stereo" plug. As a matter of fact, a balanced stereo input requires TWO of them! (-one per channel). On the other hand, an imbalanced stereo connection would require two "monaural" plugs! (ouch!)

In this scheme of things, it's not Stereo Left (tip), Stereo Right (ring) and Return (sleeve) but instead Signal (tip), Balanced Return(ring of a TRS Plug) and Imbalanced Return (sleeve of a TS Plug)

When I first encountered this, it made my head hurt!

I'm hoping this doesn't apply to you. If your inputs are always balanced, either TRS or TS might work, but I'd like to let the manual speak for itself.

If it doesn't apply to you, please try to forget it: you may sleep better!
.

TS Plug(Left) vs. TRS Plug (Right)

[Brian Fretwell]

Ethan,

I don't think an imbalanced connection is the way to go if it is a choice. Eumig 800s often have grounding issues and connecting imbalanced can give you a ground loop.

How this manifests itself is something like this: Have you ever stood next to a speaker, for example a public address system, and heard a low, buzzy tone always coming out? That's what we are trying to avoid here.

The first time I hooked a projector into an Amp, I had this and it sent me back to the internal speaker for a couple of years it was so nasty!

Unfortuantely with some Eumig projectors that it more the hum bucking coils being out of adjustment, not an earth loop. I'd compare the output an extension speaker with that through the external system before deciding what it was.

[Steve Klare]

Hi Brian,

Actually it's pretty easy to tell. If it's just amplifier hum, when you run the volume up and down the hum comes up and down with it. A ground loop is always there, even with the amplifier turned down to minimum. At the same time, fixing the ground loop does absolutely nothing for amplifier hum: that's a battle for another day.

I started seriously messing around with this maybe 2008-2009 and I found the internal grounding on my own Eumig 800 was pretty bad compared to an Elmo ST. I was measuring several hundred millivolts between that DIN Pin 2 and the third prong on an outlet strip it was plugged into. I found that the third prong on the machine's power inlet wasn't connected to the main chassis, but to the frame of the power transformer. I took out one of the mounting bolts and put a star washer under it and the several hundred millivolts dropped way down. I've read stories of this connection becoming so poor someone actually got shocked by one of these. (maybe someone didn't re-tighten those bolts all the way...)

This is mostly preventative anyway. Right now I'm running two Elmo ST-800s, a video projector with disk player and a Kodak Pageant through my mixer. One of the STs is running unbalanced because I want to ground that whole end of the audio system. Everything else is operating balanced. To me it's just good form, kind of like stopping at a stop sign at 4AM: it's probably not completely necessary but it takes care of trouble even before it's arrived.

In Ethan's case balanced/unbalanced might not even be a choice if his inputs are always balanced. The question then becomes which plug does he need to use to correctly hook up?