Extension speakers ohms

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original45
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Extension speakers ohms

Post by original45 » 11 Aug 2018, 19:45

Bought three extension speeker, two have no makers name but stamped made in Japan.


Both modern designs looking and have diff ohms marked internally on speeker.
One 2ohms the other 4ohms.

After going over ohms with headphones I believe I can't use these on a 8ohm radio would this be accurate ?.
Or would low volume be ok ?.
However I would not risk the radio for a speeker.

The last is a pye branded speeker, the actual speeker itself has a sticker on saying Elac made in England however has no ohms Mark.
Quite a nice old school speeker silver holed grill with pye in corner black edged case front and a light sky blue back case.
Anyone have a idea of its ohms or impedance ?.
Only clue is it has rather a heavier guage speeker wire attached.

Thanks again.

Tim
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Re: Extension speakers ohms

Post by Tim » 11 Aug 2018, 21:47

The impedance of a speaker is usually printed on the back (magnet) of the actual speaker itself, a number with a sort of horseshoe symbol beside it, (Greek symbol for Omega) you will need to remove the rear panel of the case to see it, it will most likely be 8 Ohms.

original45
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Re: Extension speakers ohms

Post by original45 » 12 Aug 2018, 06:17

No marking on the one Tim.the others are clearly marked 2 and the other 4ohm. The elac inside the pye brand like a pastel blue colour has no ohm marking on that I can see either.

These were off a old amateur guy ,I automatically thought they would be 8 ohm but I was wrong .

I'm wondering if their of no use individually if I wire the two or three speakers together +to + -to - if this will raise impedance to 6 ohm or with all three higher even.

Maybe he had radios of the same drive on audio speeker impedance I imagine.

Cornelius
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Re: Extension speakers ohms

Post by Cornelius » 12 Aug 2018, 07:25

You would have to connect the speakers in series to raise the impedance, not in parallel as you describe it. :)

It is my belief that a 4 Ohm speaker would be ok on low to medium volume on a reasonable modern radio, but 2 ohm would be too tough/risky...
But what do i know?! :D

paulears
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Re: Extension speakers ohms

Post by paulears » 12 Aug 2018, 13:50

2 Ohm speakers (VERY rare as extension speakers) are too low a rating for an amplifier designed for 8 Ohms - but you could simply wire one of these, in the circuit - this would make the radio amplifier happy, but you would lose a little volume. If you want a rough and ready measurement, simply stick a multimeter oil the Ohms scale and take a reading. Because this isn't AC the reading will be close but not dead accurate. An 8 Ohm speaker will read low - about 7 Ohms or so.

https://www.ebay.co.uk/itm/5-X-6-8-ohm- ... SwaEhZDYLy

original45
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Re: Extension speakers ohms

Post by original45 » 12 Aug 2018, 14:38

That's what I love about tm 1. You guys are just brilliant.
I will try measure the ohms as you say.
But out of safety to the radio amp will add the little brown micro sausage resisters.
I presume I just solder to the plus on the speeker wire inside the speeker casing or box.

original45
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Re: Extension speakers ohms

Post by original45 » 13 Aug 2018, 19:43

paulears wrote:
12 Aug 2018, 13:50
2 Ohm speakers (VERY rare as extension speakers) are too low a rating for an amplifier designed for 8 Ohms - but you could simply wire one of these, in the circuit - this would make the radio amplifier happy, but you would lose a little volume. If you want a rough and ready measurement, simply stick a multimeter oil the Ohms scale and take a reading. Because this isn't AC the reading will be close but not dead accurate. An 8 Ohm speaker will read low - about 7 Ohms or so.

https://www.ebay.co.uk/itm/5-X-6-8-ohm- ... SwaEhZDYLy
Measured speakers, one is 2ohms the other pye is 3 ohm the one I knew was 4 ohm is 4ohm.


Ordered those resisters.
Do they go any particular way around and is it just one on the plus wire to the speaker ?.

Thanks again.

paulears
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Re: Extension speakers ohms

Post by paulears » 14 Aug 2018, 17:28

Doesn't matter, just put it in either of the two wires. Solder is obviously best but a bit of chock block connector will do. Neatness wise, if you can open up the speaker, remove the wire to one of the speaker terminals and connect the resistor there, then solder the wire back to the other end of the resistor. Once you put it back together, nobody will ever know.

original45
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Re: Extension speakers ohms

Post by original45 » 14 Aug 2018, 19:19

Thanks for the reply . I'm extremely grateful and will get on to the job internally asap.

Your a star mate.

original45
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Re: Extension speakers ohms

Post by original45 » 17 Aug 2018, 15:39

paulears wrote:
14 Aug 2018, 17:28
Doesn't matter, just put it in either of the two wires. Solder is obviously best but a bit of chock block connector will do. Neatness wise, if you can open up the speaker, remove the wire to one of the speaker terminals and connect the resistor there, then solder the wire back to the other end of the resistor. Once you put it back together, nobody will ever know.
Thank you again for the information.
Today I sat and carefully revived the speeker back and soldered in the resistors.
The 2ohm speeker is now 9ohm and the 4 ohm is just over 10.

They actually sound as good as my factory pama 8 ohm extension speeker so I'm very pleased and learnt something new.

The old vintage Elac speeker in the pye brand sky blue case I havnt modified from its 3ohm .
I shall leave as it is for now until I decide further if it would better suit vintage rado equipment of same impedance .
ELAC I understand are quite a old company who made high quality speakers in England.

Very pleased,Just thought I would up date you all.

Thank you.
Last edited by original45 on 17 Aug 2018, 19:32, edited 1 time in total.

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Re: Extension speakers ohms

Post by The Collector » 17 Aug 2018, 19:21

You can't date me, I'm a happily married man ;)

original45
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Re: Extension speakers ohms

Post by original45 » 17 Aug 2018, 19:36

Lol, I don't know why but I think my tablet goes very slow on tm 1 . Even typing words it will miss whole words out.
Weird.

But at least I know where I stand with you know. :roll:

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