** 1970 B15N EXTENSION CAB

jbshowah · #1 08-29-2011, 09:37 PM

Trying to add an 8 OHM extension cab to my B15N and need advice on a couple of decisions I have to make.. debating between the Eminence Beta 15a 200W or a Jensen Alnico 50W. Would it sound odd to have an original fliptop square speaker running beside a new speaker or would it matter?

Also, I have a cabinet here that will work to house the extension speaker but wondering if the fliptop sound is dependent on the way the original cabinets are built.. any thoughts?

**garmenteros** · #2 08-29-2011, 10:48 PM

I've got a jensen alnico 50w in mine and it sounds pretty sweet but can't handle much power. I'm interested in choices for extension cabinets as well...

JimmyM · #3 08-30-2011, 01:43 AM

It would make a difference to have two different kinds of speakers running rather than keeping them the same. It's possible there could be destructive phase interference when using two different speakers or cabs. It's very unpredictable though...sometimes there's a lot, sometimes not so much. Only way to tell, unfortunately, is to try it. That's why I'm a firm believer in matching cabs with matching speakers.

I'm running out of gas and my brain has ceased functioning well, but I'll try to come back to this later today after I get some sleep and try to give you a more complete answer. What brand speaker is in your B-15N? It should be CTS if it's original.

jbshowah · #4 08-30-2011, 08:32 AM

CTS is in there currently .. would I be able to find one of those anywhere ?

JimmyM · #5 08-30-2011, 09:56 AM

Only used. They do pop up on Ebay from time to time. Now the Beta and Delta 15 sound like the 60's CTS speakers, but the 70's CTS's were darker without as much high end, as I guess you know. Great sound, but hard to find in a modern speaker. And while the Beta and Delta are the best modern equivalent, I don't think they work as well in Thiele cabs as they do in the double and single baffle cabs because the bigger size cabs does a bit of a mid scoop with a more full range speaker. The Altec 421a is considered THE speaker to put in Thiele cab B-15's for that reason. Only available used, though.

So if you want to stick with the 70's CTS sound, your best bet is to buy an orphaned cab with one in it or get Fliptops to make you one and then look for a CTS on Ebay. They pop up fairly regularly. Or go Altec, which is a more expensive solution.

jbshowah · #6 08-30-2011, 11:00 AM

Ah, found one with an Altec speaker in it but the guy also has the CTS that he is willing to sell. What do yall think, which sounds better in an extension cab ?

coreyfyfe · #7 08-30-2011, 11:14 AM

Matching the speakers in the two cabs would probably be best, but that altec usually regarded as a much better speaker.

JimmyM · #8 08-30-2011, 11:37 AM

Word.

jbshowah · #9 08-31-2011, 08:09 PM

well both are 8 ohms so they would be interchangeable. I know sometimes guitar players purposely get 2 different speakers in a cab for 2 different sounds. The Altec should be an equal or better speaker than the CTS. The guy said it has both an XLR and a 1/4" option for the speaker input which is handy. Will it be safe to stack the amp on top of the extension cab?

JimmyM · #10 08-31-2011, 08:24 PM

Yes it will. I never did it with a Thiele cab, but I stack with my double baffle cabs on practically every gig I use my B-15N. And the Altec will no doubt be a better speaker than the CTS. CTS was good, and in some cases like the old 810's, superb, but Altecs and JBL's were king back then. But it's possible you may like it, and it's definitely the cheapest solution, so why not give it a shot?

beans-on-toast · #11 08-31-2011, 08:41 PM

Quote:

Originally Posted by jbshowah

Will it be safe to stack the amp on top of the extension cab?

Normally this isn't a problem. Sometimes you can run into problems with vibrations when you stack cabs.

A good set of rubber feet on the cab usually prevents problem vibrations between the cabinets. The cabinets should sit square and not wobble when you rock them.

If the cabinets are not sitting square, you can fix it with a pad of high density foam. I've used rectangles of 1/2" interlocking mats like the type that you can get at hardware stores.

jbshowah · #12 09-01-2011, 09:53 AM

i read that there was a bolt that hooked the vintage extension cabinets (earlier models from the 60's i believe) to the main cab, utilizing the dolly screw hole on the bottom of the amp .. anybody ever seen this

Vintage-Blue · #13 09-01-2011, 11:40 AM

Quote:

Originally Posted by jbshowah

i read that there was a bolt that hooked the vintage extension cabinets (earlier models from the 60's i believe) to the main cab, utilizing the dolly screw hole on the bottom of the amp .. anybody ever seen this

I'm not sure but I think it was the later 60's models that did that. I think the extension cabinet lid could be attached to the bottom of the other cabinet like a dolly would and then you could latch that whole assembly onto the extension cabinet. I've seen photos somewhere. Check at fliptops.net - that may have been where I saw them.

beans-on-toast · #14 09-01-2011, 06:39 PM

That sounds like a really good idea.

Fender and others have hardware for attaching heads to cabs at the sides for when they were tilted back. It is available from aftermarket sources.