Speakers.Who manufactured them.

[James R]

Back in '78 I had to remove 4 12" speakers from an old Marshall Column to ship them here state side. They are great speakers now mounted in a nice cab and work real well on a SC 120R. Trying to find out the manufacturer of these excellent speakers. They have long slim magnets about 5 inches diameter and the following numbers on the magnets. 68-31-AH 2422-258-51004, no other markings that I can see.
I would appreciate any and all input.

[soundguruman]

The speakers were manufactured by Phillips Electronics, in the 31st week of 1968.
They are very sought after and impossible to buy, extremely rare. However I think some speaker shops will recone them, there are no more original parts to rebuild them.

[James R]

Soundguruman that is a great piece of information. I thought they were something special. Do they have any specific attraction to make them sought after apart from being great sounding speakers.
Thanks a whole bunch. I am grateful that we have knowledgeable people like you around.
Is there any reason to not use them as guitar speakers as they were intended for PA service.

[soundguruman]

Soundguruman that is a great piece of information. I thought they were something special. Do they have any specific attraction to make them sought after apart from being great sounding speakers.
Thanks a whole bunch. I am grateful that we have knowledgeable people like you around.
Is there any reason to not use them as guitar speakers as they were intended for PA service.

You can use them for guitar, there were similar speakers in the (old) 6X10 cabinets. These were Hi Fi speakers really. They burn out pretty easily but they sound good. They have extended high frequency (really upper mid). It's super hard to find them because the paper dry rots when exposed to humidity and dirt for years and years. The voice coil comes lose from the cone, etc... So, if you have some good ones, it's because somebody took really good care of them when they were new. Just luck.

The ONLY place to find any info, "if" it exists, is to call the Marshall Factory in Milton Keynes, and beg to talk to one of the engineers. They are really nice people. "If" anything is left at all in the way of documentation, they would probably send you copies. BUT you are wishing, because that goes all the way back to the start of Marshall production, before the dawn of dinosaurs, before cave drawings.

Early Marshalls were made out of Hi Fi parts. The speakers and transformers were all hi fi parts. As demand grew, Marshall started using more heavy duty parts, that exceeded hi fi specifications. There used to be a lot of speaker and transformer failures, until the heavy duty parts were introduced into the equipment.

There IS a strategy, that has found popularity among Marshall Collectors:
You have two cabinets, OR two stacks. After about 40 minutes, you PAUSE, and you plug your amp into the alternate stack.
This way, you never overheat the speakers.
Run the speakers for no more than 40 minutes, then change speakers.

You will notice that even today, at Rock Concerts, many guitar players still use this method, to avoid overheating the 30 watt speakers, in the 4 X 12 cabinets.
(Think about it, those 30 watt speakers get hotter than the surface of Mercury)

[Steve Conner]

Hotter than the surface of Uranus, even. If they really are rated 30W, and it is an optimistic hi-fi 30W, then using four of them with a Sound City 120 might be somewhat risky.

I thought those two stacks were just there to make the guitarist twice as loud.

[James R]

So the consensus is that if I use them I should use them on lower power than the possible rating of 30 watts per speaker or use them for vocals. With the clarity they have I would think that they would be very handy for recording or Mic up. As I no longer do that, getting old you see, perhaps I should consider selling them to someone that can use them. Just a thought.
I have a pair of 50 Watt Bakers from the 70s that were hardly used that may well suffice for use with the SC 120R. Oh by the way after a bit of bottle swapping the SC120R recently came back to brilliant life. Beautiful sound with no noises. Got to fix my WEM copicat next.
Thanks a bunch for for all the information and guidance.

[J M Fahey]

Use them for Voice, for which they work very well.
Or acoustic guitar.
Forget electric guitar or any heavy sounds, their clarity and extended range will make them too buzzy.
They have whizzer cones, and the pole piece is wrapped in copper, to lower the inductance, or alternatively have an aluminum or copper shorting ring just below the pole plate, all to lower self inductance and smoothen and extend the frequency response.
"Very much" doubt an Marshall Engineer knows too much about them, they just bought and used them.
If anything, an old Philips Engineer will.
I have stashed somewhere a 70's book called "Loudspeakers" or "Acoustic Transducers" by Philips (Eindhoven - Holland) where they explain it all, have response curves, magnetic flux, VC details, the works.
Try to find it, though.
A funny detail: some of them had octogonal pole plates, instead of the classic round ones.

[James R]

Thanks for the additional information JM. Based on all the knowledgeable input from you guys they will be used for vocals from here on.
Nice to own a piece of history however small.

[soundguruman]

Thanks for the additional information JM. Based on all the knowledgeable input from you guys they will be used for vocals from here on.
Nice to own a piece of history however small.

MEF should have a "museum" and this should be in it, because the speakers drip mojo.