What kind of driver comes with 4 wires?

[Atilla]

Here is the driver.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

Here is the class-D section:

An externally hosted image should be here but it was not working when we last tested it.

And this is the box with the bolted trafo inside.

An externally hosted image should be here but it was not working when we last tested it.

(Aaaaand the JS of the forum prevents the links from opening.. ugh. )

 

[tinkerbelt]

I also have a speaker that needs 4 wires. Mine is an electromagnetic or "energised" type and lives in my early '30s HMV radiogram. It is a massively built beast that has a bracket mounted to the base of the cabinet for extra support. To look at it you would guess it must handle at least 200 watts but the amplifier actually puts out just 2 watts

 

[Speedskater]

I also have a speaker that needs 4 wires. Mine is an electromagnetic or "energised" type and lives in my early '30s HMV radiogram. It is a massively built beast that has a bracket mounted to the base of the cabinet for extra support. To look at it you would guess it must handle at least 200 watts but the amplifier actually puts out just 2 watts

In the US they were called "Electrodynamic Speakers". The speaker's electromagnetic was also a filter choke in the DC power supply. As a kid, I disconnected the speaker with the receiver still turned on. 400V DC got my attention!

 

[chris661]

Not surprised it did. 230v mains over here hurts, but 400.......

Pity those photos didn't come up too well. Perhaps you could put them over in the Gallery?

 

[tinkerbelt]

I tried to include a photo of the energised speaker but was having extension problems with Photobucket. Have now resolved this by changing browsers:

 

[chris661]

Now that is some serious s... stuff.

 

[AndrewT]

I wonder if Andrew is talking one woofer while Chris is talking two?

The tread title is about a 4wire driver.
Why would I want to wander off and talk about twin drivers?

 

[AndrewT]

Oh and the auto-ranging multimeter claims 6r0 for each coil, so that would mean dual 8-ohm?

now connect the dual voice coils in series and check that the resistance is ~12r.

If you get 3r0 you have them in parallel.

You must know the phasing of the windings to allow you to connect any signal.

 

[AndrewT]

I also have a speaker that needs 4 wires. Mine is an electromagnetic or "energised" type and lives in my early '30s HMV radiogram. It is a massively built beast that has a bracket mounted to the base of the cabinet for extra support. To look at it you would guess it must handle at least 200 watts but the amplifier actually puts out just 2 watts

being an old high efficiency speaker, I suspect the signal input power should be <50W and possibly <20W

 

[Atilla]

now connect the dual voice coils in series and check that the resistance is ~12r.

If you get 3r0 you have them in parallel.

You must know the phasing of the windings to allow you to connect any signal.

Oh, it's good, all the wires are marked appropriately. I just need to source a few parts that I'm lacking and I'll get it working.