Bandmaster speaker help?

[Hunter008]

Hi, I recently acquired a 1970ish Bandmaster TFL 5005D.
I had the head fixed at an amp shop. And the cabinet looked at by a guitar tech friend of mine.
One of the speakers was dead in the water. So I shipped it to a guy that fixes speakers. He wanted to know the resistance, Ohms,and if it was wired in series or parallel?
All Greek to me. I know that the back of the amp says 2 Ohms at 45 watts RMS. ( with the option for 2 speaker cabinets).
My friend tells me that the good speaker he tested measured 6 ohms.
So it's a 2x12 cabinet. What would the speaker ohms be? and how should it be wired? in series or parallel? So that it matches my amp head at 2 ohms.
Thanks for any help in advance.

[Keethlawrence]

Let me try to help. The ideal 2X cabinet for a 2 ohm load would be two 4 ohm speakers wired in parallel. That would give you a perfect match at 2 ohms. If they were wired in series it would give you 8 ohms.

I am not sure about that 6 ohm speaker that is in your cabinet. Is it original? And is it a Fender cab? 6 ohm speakers, while common in stereo amplifier applications, are not often seen in guitar amps...

If you had two 6 ohm speakers, in parallel they would be 3 ohms. In series..6 ohms. Not a perfect match, but OK.

It looks to me like maybe someone at some time just grabbed a speaker they had laying around and put it in there..

The good news? Fender transformers were designed to handle large mis-matches with no issues. You will lose a little in output, but it won't hurt the amp.
My blackface 'Bandmaster looks for 4 ohms. But it works just fine with an 8 ohm speaker. (But even better with a 4!)


Now to confuse things even more. There are a lot of Bandmasters out there that have had their output transformers swapped for newer/larger ones. The transformer dictates what ohms the speakers should be. So even though it is printed "2 ohms" on the back of the head, that may not be correct anymore. Some aftermarket transformers are switchable between 4 -8 -16!
So you should have the looked at before you invest in new speakers that give you a 2 ohm load.
You just might need 8 ohms.
Again, if you are close it will be OK. But those of us who love Bandmasters want them to be perfect!
Good luck

[Hunter008]

Thank you very much. I think the tech guy is reading it wrong. As far as I know. The speakers are original.
It's probably 4 ohms or 8 ohms.
I'm just trying to find out which.
And how to wire it. I want it to be right.
I never imagined the speaker cabinet would be a bigger problem than the head. (Which needed a lot of work).
Just trying to sort it out for the speaker guy.
There's numbers on the back of the speaker.
And that should tell him a lot.

[Hunter008]

I just spoke to the guy that fixed my amp.
And he says they used 8 ohm speakers wired in parallel.
That would make it 4 ohms.
And if I have 2 cabinets hooked up to the amp.
That would make it 2 ohms.

[Keethlawrence]

And if you used just one cab that would be 4 ohms which is just fine for that amp.