8mm Forum: Eumig mark s extension speaker rating?

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Posted by Jason Moffatt (Member # 4416) on March 29, 2018, 05:21 AM:

Hi all, i have a eumig extension speaker originally designed for the mark s from the late 1960s.I have been using this with the eumig 800s and various other sound projectors i have.The label that would have had the ohms rating on the speaker is not there so i’m not shure of the rating, does anyone know? as i dont want to risk damaging the amps on the projectors if its the wrong rating.

Posted by Steve Klare (Member # 12) on March 29, 2018, 05:44 AM:

Hi Jason,

It's most likely 4 Ohms, or let's say if you aren't sure this is the safe bet.

With an 800 series Eumig you can't do any harm even if we bet wrong and it's really 8 Ohms.

Anything built for an 8 Ohm speaker would be operating the output transistors in the amp hotter than they should be and make them fail sooner than they otherwise would. Considering they are old enough to have kids in college (tech school, of course!) they need to be treated with care.

8 ohm speakers are common as dirt. You may have some to spare right now.

Posted by Jason Moffatt (Member # 4416) on March 29, 2018, 06:31 AM:

Hi steve, thanks for the reply.Yes i thought is is probably 4 or 8 but i just checked the filmkorn database and it has the eumig mark s projector output rated at 2ohm, so maybe this extension speaker is 2 as well.

Posted by Steve Klare (Member # 12) on March 29, 2018, 06:53 AM:

TWO?!!!

I've seen 4 Ohms and 8 and heard of 16, but 2? This is a new one on me. (-or maybe a very old one.)

This one is probably not a good idea to use. For an 8 Ohm machine (like any Elmo I've ever owned) this is pretty much a short circuit.

Posted by Jason Moffatt (Member # 4416) on March 29, 2018, 10:13 AM:

Maybe if anyone else has one of these extension speakers with the label on the rear of the speaker itself inside the box intact they could check to see what the rating is.Unfortunatly i am unable to post a picture but Its not the later ones made for the 800 series.It’s very early, probably mid to late 1960s has eumig mark s on the top left corner and opens up into two seperate parts so the projector can be stored inside.I have been using it for a while now with no problems and it has a good clear sound but i just want to double check.

Posted by Maurice Leakey (Member # 916) on March 29, 2018, 10:32 AM:

I have one in its original box with a label marked "Johnsons of Hendon Ltd. Carrying case with built-in loud speaker for Eumig Mark S 8mm sound projector."
There is a white paper sticker attached to the label which reads "5 ohms".

Posted by Dominique De Bast (Member # 3798) on March 29, 2018, 11:57 AM:

This is what the site says but sometimes There are some mistakes.

amplifier output: 5 W (2 OHm)
frequency response: 75-6,800 Hz at 18 fps, 75-9,000 Hz at 24 fps
recording: magnetic recording on main track, sound-on-sound
recording level control: auto
input terminal: Microphone (2-50 mV, 400 kOhm), Phono (2 mV-1.9 V, 400 kOhm-200 kOhm)
input jack: 5-pin European DIN
output terminal: External Speaker (5 W, 2 Ohm), Earphone
output jack: Ext Sp: 2-pin DIN; Ear: mini jack
built-in speaker: 95 mm diameter, 5 Ohm

By the way, I have this projector but cannot have the correct focus on all the picture. Does anyone know how to fix that ?

Posted by Steve Klare (Member # 12) on March 29, 2018, 04:52 PM:

It's possible that Eumig is doing a little of what's called "specsmanship" here. As the impedance of a speaker goes down, the power it pulls out of the amp goes up. So they say with a 2 ohm speaker you get up to 5 watts. They don't sell you the machine with a 2 ohm speaker because that would allow you to push the amp too hard.

You get a 5 ohm internal speaker. You only get 2 Watts, but you also don't give Eumig a bad reputation by being part of the parade of blown amps at the repair shop either.

Posted by Jason Moffatt (Member # 4416) on April 03, 2018, 06:17 AM:

Ok, so lets assume it is 5 ohm then.Would it be ok to use with projectors that have a amp rated at 4 or 8 ohms ?.

Posted by Steve Klare (Member # 12) on April 03, 2018, 06:24 AM:

For an 8 Ohm rated amp, the people that built and sold the thing would say "no", especially if the warrantee is in effect.

At low volume levels, it might even be OK, but if you got in the mood to crank it one day (got Fantasia?) you could go beyond the power rating of the amp and cook something expensive in there, and in this case maybe something obsolete and irreplaceable.

For a 4 Ohm machine, it's OK. Probably the worst that will happen is if you go for more watts, you won't get quite as many as with the 4 Ohm speaker. It's even possible since you'll have to drive the amp harder to get the same volume you'll hear some distortion, but I don't think you'll hurt anything.

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