Install a SpeakON in a Mesa Cab; which terminals?

[edwardofhuncote]

My Wire-Dunce status has been well-documented here. 

Any idea which terminals the speaker leads should go to? This is an EVL-15L in a Mesa-Boogie Diesel 115. The 1/4" jack has gone wonky... I have a SpeakON... time to punch the hole out bigger and quit dealing with my cab cutting out.

Thanks in advance.

~Ed of H.

[xlrogue6]

You want 1+ for the white wire and 1- for the black wire.

[edwardofhuncote]

Thanks Kent!

[edwardofhuncote]

So I replaced the stock 1/4" jack on my Diesel 115 cab with a new SpeakON, got a nice clean job too, thanks to some help from one of the electricians at work who punched out the plate for me. Wired the speaker back to it with Kent's advice here... (Thanks Again, Kent)

...but the dad-gum thing is still not right. I'm not even sure quite how to describe what it's doing. The speaker is working intermittently, but I have realized now, there is a pattern to it. When first connected to the amplifier, regardless of which amp (I have tried several) it will work for a few seconds, then stop. If you listen very close, it is still emitting sound, but very, very faint, distant, but there... like it's trying to work. After a few minutes, if I persist in giving it signal (these are Class D amps, no unloaded tube amp at risk here...) the speaker will resume normal operation. It sounds completely fine, at any volume. There is no distortion, no cutting out, no static, it's perfect... and these things sound positively vicious when properly sourced. It will continue to work until I cut the rig off for any period of time and allow it to "cool down". Once restarted, (after 30 minutes or so have passed) the whole process begins again. Obviously, this isn't workable in a gig scenario.

What the ham-sandwich have I got here?! A speaker cabinet that needs to warm up?! That can't be right. I figure after the Holidays I'll tag-up with the folks over at Mesa-Boogie. Andy thought if the internal cab dimensions were close enough, that the 15" driver they use with the new Subway 15 might be a suitable replacement, but he would have to run the numbers. (ain't it great to have a real-live person who actually knows what you are talking about?) I've got a nearly 30-year old cabinet they're willing to help me work on. Just because it has their badge on it.

Before throwing in the towel, especially since those EV-15L's aren't available anymore, I'd like to know if the speaker is actually bad? Anyone heard of this?

Leave it Ed of H. to come up with a wacky one... 

[elwoodblue]

Are there solder joints at the speaker terminals or spring posts?


One of the leads from the terminals to the cone might be failing.
 
 If it's the coil...best to replace or recone before things get worse.

[edwardofhuncote]

Thanks Bro. Elwood.


Pictures of the speaker connections in post 1... little springy-thingys. They are snug. Continuity (to the voice coil?) beyond that point, I am not sure how to be certain of.

[elwoodblue]

D'oh...looks snug.


No rubbing coil? odd smells?


I'd oh so gently fiddle with the leads to the back of the cone to see if that
brings a clue.
 Maybe Wolf has some insight.
It sounds like something is expanding with heat making a better connection,
most possibly under the dust cap or in the coil.


Might be a good excuse to try a lightweight neo driver ? I recall Wolf touting Faital brand drivers.
 

[edwardofhuncote]

Nope, nothing like that... it just 'wakes up and starts making bass sounds', and continues to until I cut it off again. I could accept the theory of something expanding with heat, and thereby making a connection... that makes sense. But where? Anywhere that's happening doesn't sound too fixable. 

Yep, Faital drivers are nice. I ran a pair of them in a Mesa Scout 12 stack for a while. FWIW, weight is no issue. This hefty Bad Boy on wheels lives in the Harwell-Grice Band Truck. (when it's not at my house getting worked-on...) 

[xlrogue6]

Did you solder the leads to the terminals on the Speakon, or install quick disconnect terminals? If everything was OK when using the 1/4" jack, then there's an issue with the Speakon. The symptoms you're describing sound like a cold solder joint could be your issue, or if you're using quick disconnects one or both is not clamped on the lead properly. (Pro tip--if you're using these you want bare wire, not tinned in the connector. Also, it's very difficult to get a solid crimp on those connectors without a good crimping tool--those combination wire stripper/crimping tools are notoriously bad at crimping those!)

[edwardofhuncote]

Thanks Kent;

It is behaving exactly as it was before I upgraded to the SpeakOn by replacing the 1/4" jack. I thought (wrongly) the jack was the problem. I just had not yet recognized the pattern. 

I did install terminals onto the wire leads from the speaker to the new SpeakON, but they are the solderless type you crimp with a tool. I was quite conscientious of that contact point, and got a very good squeeze on each lead. [tug.... and... tug... good] 

[lbpesq]

I would try to isolate the issue by swapping out the speaker and see if the problem persists or disappears.  At least then you will know if the problem is with the speaker or the cab/wiring.

Bill, tgo

[xlrogue6]

Well, in that case you're pretty much down to a case of Weird Driver Issue.

[edwardofhuncote]

Thanks All; yeah... this is a weird-o-rama. I'm going to tag Andy over at Mesa-Boogie after the Holidays. (already talked to him over on TalkBass) I have practically nothing in this old cab, so I don't mind springing for a new speaker, though I'd rather fix this one if possible. We'll see what he thinks. Hey, it ain't like there's any big shows upcoming... and if by some long-shot chance one were to come in, I can always load up the old Mesa WalkAbout/Scout 15. My Alembics have no problems getting along with that rig either. My frail frame though, doesn't much care for hefting 78 lbs of it into the gig-mobile.

Thanks Again. I'll post back what the verdict is.

[keith_h]

Have you tried putting and ohm meter on the speaker and jiggling/bumping wires/cabinet/speaker frame to see if the values change?

I assume you have verified it isn't the amp by trying a different cabinet.

As an aside I do have a couple of raw Eminence Beta 15's I have used for about 15 hours that I'm looking to sell for $40 ea (street price new is around $90). I had bought them for some old Road PA cabinets where the original speakers had rotted and I had planned to use for a rehearsal PA. I've since dumped the cabinets but kept the speakers since they were practically new. Pop me an email or give me a call if you want to talk about it further. 

[edwardofhuncote]

Have you tried putting and ohm meter on the speaker and jiggling/bumping wires/cabinet/speaker frame to see if the values change?

I assume you have verified it isn't the amp by trying a different cabinet.

As an aside I do have a couple of raw Eminence Beta 15's I have used for about 15 hours that I'm looking to sell for $40 ea (street price new is around $90). I had bought them for some old Road PA cabinets where the original speakers had rotted and I had planned to use for a rehearsal PA. I've since dumped the cabinets but kept the speakers since they were practically new. Pop me an email or give me a call if you want to talk about it further. 

Hey Keith, yessir; I finally broke out my little Acoustic Image amp to test with, if for no other reason than it's 2 or 3 lbs were easier to deal with than my rack. I tested the F-1X & Crown power-amp I usually use with a couple different other speakers and had no failures. My trouble is limited to just this one, and only as I have described.

I may take you up on one (or both) of those Eminence drivers, if they would work with my cab, spatially.

*if you check my wire-dunce card, you'll see that I am prohibited from handling devices like ohmmeter and tricorders, etc. Our Chief Electrician won't even let me borrow a screwdriver.