CTS Speaker ID ?

[stratmanx]

Hello all.

I've got an original Kustom tuck and roll loaded out w/ 3 12" CTS speakers, big square magnet on the backs.

The test out to be 8 ohm each.

Codes on them are : 5812241 137-6841

also, there are the following number on each respectivly:

#1 20021
#2 20047
#3 20049



I'm curiuous as to what these numbers tell me.

Also, the reason Ive got it opened is that my new (Old!) 1974 Marshall 50W output transformer was getting a bit hot after a few hours of playing.

Knowing that this isn't correct, I oepned the back up and discovered that only two of the speakers where connected, both in parallel, giving me a 4 ohm load.

The head was set on 8 ohm.. Not a good thing, I know.

So, having said that, I got rid of the cheesy speaker wire and put in 16 awg Monster cable.

Setting the amp now on 4 ohm to match.

Another question is, if all 3 are hooked up, what would be my effective load in parallel?

Another irony of this is, I've been using this cab with my 1968 50w Plexi and its been all smiles, the output tranny gets a wee bit warm, but notr hot like the '74..

Guess I've been REALLY lucky !!

BTW, the tone of thiscab is to die for. unbeleavable !! Breaks up VERY sweetly, and puts any of the 800-900 series Marshalls to shame !!

Thanks folks !!

[Gooch]

5812241 is probably the CTS part number. 137-6841 means they're made by CTS in the 41st week of 1968. The other numbers are probably serial nos. All three speakers in parallel will give you 2-2/3 Ohms - no good. If you hook all 3 in series-parallel you could get 5-1/3 or 12 Ohms.

[stratmanx]

Good news..

Decided to just re-wire the cab up using only two ot the 12's and wired it in parallel.

Used Monster THX 16awg cable,

Set the Marshall on 4 ohm as the cab is now wired for 4 ohm, and OH BOY !!

This thing flat out rips !!! The output tranny gets slightly warm, but nowere near as hot as before..

A '74 Marshall 50w into two 12" old CTS speakers is GOOD thing !!!!

[Roy Boltz]

I'm curious about those, how do you know they are CTS? do you have pics? I have a pair of 12's with square magnets but I don't realy know what they are , maybe Eminece? they are black in color so that's why I think they are Eminece but the look a bit different then some of the Eminence square magnet 12's I've seen.

[Gooch]

137 is the EIA code for CTS. Eminence is 67.

[Roy Boltz]

Thanks Gooch, the first two digits are 67 so they are indeed Eminence.