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Rewiring a cabinet

giacomini

giacomini

Dec 14, 2008
1,273
77
41
Florianopolis - Brazil
Disclosures
Endorsing: Copetti Guitars
#1
So I got a sealed 210 cab in a trade and it rattles and slightly distorts when I play certain notes.

The cones look great, no tears or holes in the front or back.

One thing I noticed when I took those speakers out is that the wires, jack and connectors look thin/cheap.

I want to redo the wiring but I don't even know where to start.

What kind of wire should I get?

Can I use a regular 1/4 instrument jack for the input?

I did a search, but nothing this basic is covered in the FAQs...




_______________________________________________
UPDATE:

Since the wiring harness most likely isn't the main problem with this box, I decided to refurbish the inside, adding some bracing.
 
#3
Anything bigger than 16awg wire is a waste of money, the runs of wire are not long enough. Any good quality 1/4" jack is fine. there is no different jack for inputs and outputs (instrument/speaker).

Your rattles and distortion are likely loose wood panels/air leaks that need to be reglued in the cab. Does the cab use any braces to keep the panels solid?
 
#5
OK, so if wire is not a problem, could small connectors instead of plain solder cause any problems? The wires (speaker end) are secured with those small electrical connectors and they feel kinda loose...

I did not notice any bracing, there's insulation all over the interior walls. I will check it the next time I open it up.
 
#9
So I will check the inside of the cab.

I'm ruling out the grille because the rattle was there even when it was out.

I'll post pictures if I find something odd.

Thanks guys, you saved me from dealing with my old enemy the soldering iron :D
 
#10
giacomini said:
So I will check the inside of the cab.

I'm ruling out the grille because the rattle was there even when it was out.

I'll post pictures if I find something odd.

Thanks guys, you saved me from dealing with my old enemy the soldering iron :D
Click to expand...

If you have a rubber mallet you can use it to "pound" on the cab panels to find a "lose" panel that needs re-glue. The panels should sound solid and not have any lingering tone/rattle. Air leaks are tougher to locate.
 
#11
This is the cabinet:

210bs_06.jpg


It would look good with a Micro CL head, but since I have a Micro VR I already ordered some silver/black/blue grill cloth from fliptops.net to make another grill...

Lets get to the innards:

It turns out I did have to heat up my soldering iron...

This time I disassembled the cab thoroughly and found some surprises:

210bs_01.jpg


The jack wires just went thru the lugs and were twisted. There was a little drop of solder but it wasn't holding anything anymore.

And this:

210bs_02.jpg


Same thing here, plus electrical tape. :rollno:

So I grabbed my soldering iron and fixed the solder joints.

It is all working, I did the 9v battery trick to check polarity (I marked the lug terminals + and - so I won't mess up while reassembling).

The final impedance is around 4.5Ω (the cabinet is marked 4Ω, each speaker reached around 8.7 - 9Ω in my multimeter).

210bs_03.jpg


B-string said:
If you have a rubber mallet you can use it to "pound" on the cab panels to find a "lose" panel that needs re-glue. The panels should sound solid and not have any lingering tone/rattle. Air leaks are tougher to locate.
Click to expand...

Now about the box. It all looks and feels sturdy.

I did the rubber mallet pounding and it sounds like an empty wooden box should (very dry in the corners/joints, "open" and "resonating" when hit in the middle of the panels).

Nothing sounds/feels like it's loose. Thanks for the tip!

I did notice a few issues: as you can see in the next picture, there are 4 mounting holes on the top for the matching head of this cabinet:

210bs_04.jpg


Those holes went thru the wood and there are t-nuts on the other side. A rather small air leak but I decided to plug them up. I found some dowels that fit just right, hammered them in and dropped a bit of glue on top.

Interior of the cab:

210bs_05.jpg


The lining doesn't cover all the walls, the corners are bare wood as well as the back of the baffle.

I will get some of that lining tomorrow to patch up the corners. Is it necessary to glue some lining on the back of the baffle?
 
#12
Don't cover the baffle board (back side of the board the speaker mounts to). From the "sound" of the panels it could use a brace from the baffle board to the rear panel at a minimum. 3/4" round dowel can be used if space is tight. When you tap the panels it should be tight and high pitched, not bassy or resonate.
 
#13
giacomini said:
Now about the box. It all looks and feels sturdy.

I did the rubber mallet pounding and it sounds like an empty wooden box should (very dry in the corners/joints, "open" and "resonating" when hit in the middle of the panels).

Nothing sounds/feels like it's loose. Thanks for the tip!
Click to expand...

What does the phrase "open and resonating" mean? A well-built cabinet should have a very dead sound like a solid block of wood. If I were to describe a cabinet with those terms then I would want to add bracing to "close" it down.

This could be merely a case of a difference in terminology so please clarify. :)
 
#14
I agree with the vets (why not?; they taught me), that it is not wiring. There is an electrical connection or there would be no sound; if your speakers are cutting in and out, then maybe squeeze your connectors tighter and reconnect.
From pics, I can't see the wood joints in the cab. I would inspect them. There's expanding glues like gorilla glue that you can apply allowing gravity to suck it between wood panels (Sir Issac Newton, in the house!). B-string's bracing could be the cure, for sure.

curious to know your findings,
fnord!
 
#15
I will surely check all those things you pointed out tomorrow!

B-string, you said that the brace connecting the front and rear panels could be a round dowel. Do you mean like a double bass sound post?

Forgot to mention before: there's no bracing inside this cab.

Tomorrow after work I will try to post a video with all that knocking on wood. :D
 

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