Rebuilding a set of AR4xs...help with crossover/cap replacement

[Nicholas M]

Hey all,

Recently acquired a very nice set of AR4xs. Pots are pretty dirty so I am going to try and clean/restore before I go a different route. Back to that later.

I do want to update the caps on the crossover. Here is the photo of it presently configured:

Here is are my serial numbers so XO style can be traced. I'm also wanted to resolder new leads from the tweeter to the cross over because I had to snip them to test the ohm. What's the gauge of those leads so I can find colour matching ones?

FX 39899
Tweeter ohm rating (out of cabinet): 4.8
Woofer ohm rating (out of cabinet): 5.3

FX 43162
Tweeter ohm rating (out of cabinet): 4.8
Woofer ohm rating (out of cabinet): 5.7

My very hobbyist level of understanding tells me that I need 2x20uf 250v crossover caps. My question is how to solder them into the current unit, which leads are removed, etc.

Any help and direction would be greatly appreciated. Also, in the instance of the pots not being saved, may I put in a resistor with an L pad or without? What ohm rating, and how does that can configured?

thanks!!

 

[malden]

I removed the corroded rheostat from the circuit and left the stock crossover alone in my 4x's. The sound good.

 

[Nicholas M]

i figured if I have them open, I should recap. I just don't have an idea as how to do that, hence the post. I could test and if they come back with an appropriate rating (value?) then could leave alone for now..

 

[malden]

If you're set on "recapping", I believe they are 20uF, non-polarized. They're not expensive so get several different values and experiment.

Maybe mount them on the rear baffle on the outside of the box so you can change them easily. When you find the best sound, mount them inside the enclosure.

If you connect two in parallel, the total capacitance is simply the sum of the two

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www.parts-express.com

 

[Nicholas M]

That's right. I'd like to choose the audio grade Dayton 20uf cap. I'm just wondering if I can find a user's photo of how it looks from the inside, and whether I should take the old cap off. It appears the inductor sits on top, can it be easily removed?

 

[DOBIEGUY]

Nicholas
I’ve done this repair. Clip the wires close to the old cap. Solder the new caps on those wires and insulate with some shrink tubing. No reason to do extra work and possibly connect something wrong.
Use some silicon to secure it to the cabinet.
There are too many threads here on AK about these speakers.
As for the old corroded pot, why waste time with them. Any repair will be sure to fail again.
You are in there, replace them with new.
Do a search, read the threads!
Good luck
James

 

[malden]

 

[Nicholas M]

Nicholas
I’ve done this repair. Clip the wires close to the old cap. Solder the new caps on those wires and insulate with some shrink tubing. No reason to do extra work and possibly connect something wrong.
Use some silicon to secure it to the cabinet.
There are too many threads here on AK about these speakers.
As for the old corroded pot, why waste time with them. Any repair will be sure to fail again.
You are in there, replace them with new.
Do a search, read the threads!
Good luck
James

Hey there! Thanks for your reassurance. A few clarifying points. I will use new 16 AWG wires for the new caps, but they're already insulated -- is that fine? Silicon to hold the cap, got it. Fine, if I bypass the pots, how do I connect the resistors, and is the rating 25ohm for these? Otherwise need to find appropriate pots but my search tells me that theyre quite expensive. Also, the inductor is attached to the top of the cap, I suppose this is with glue or putty? When I put in the new cap, I'll place the inductor to the size and putty that down so that the crossover can be linked up appropriately?

Thanks for your guidance here. Super excited to get this right.

 

[DOBIEGUY]

Nicholas
First, leave the old wax cap where it is. Then leave the inductor where it is.
Forget the bypass, get the replacement pots and the cap and do the job right.
You don’t want to be in that cabinet more than once.
The money you save by doing it yourself easily covers the cost of parts.

 

[Nicholas M]

Nicholas
First, leave the old wax cap where it is. Then leave the inductor where it is.
Forget the bypass, get the replacement pots and the cap and do the job right.
You don’t want to be in that cabinet more than once.
The money you save by doing it yourself easily covers the cost of parts.

If you say so!

 

[Dave1027]

You can get replacement L-Pads at Parts Express when you order your Dayton capacitors. I would definitely replace them and not simply bypass. Reason is without the L-Pads you won't be able to tweak the highs in. The speakers may be harsh and lack that comfy laid back sound character. Without the L-pads, you won't have any control.

Speaker L-Pad Attenuator 50W Mono 3/8" Shaft 16 Ohm

 

[Nicholas M]

You can get replacement L-Pads at Parts Express when you order your Dayton capacitors. I would definitely replace them and not simply bypass. Reason is without the L-Pads you won't be able to tweak the highs in. The speakers may be harsh and lack that comfy laid back sound character. Without the L-pads, you won't have any control.

Speaker L-Pad Attenuator 50W Mono 3/8" Shaft 16 Ohm

My model doesnt have a cutout in the back board for LPad inserts. I'd prefer to keep this more simple. If I replace pots, I can adjust highs manually with my receiver, no ?

 

[Nicholas M]

Ah You mean to replace each pot... Is an L pad an appropriate substitute for new rheostats? So hard to find affordable pots, and do I need additional resistors with an L pad insert?

 

[Nicholas M]

 

[Dave1027]

Ah You mean to replace each pot... Is an L pad an appropriate substitute for new rheostats? So hard to find affordable pots, and do I need additional resistors with an L pad insert?

An L-pad is a rheostat. Don't need any additional resistors.

 

[Nat]

Possibly the most elegantly proportioned speaker I have ever seen. And it appears you have the plywood, rather than particle board cabinets which some people think sound better.
Even so, they are small two way speakers, so don't fret too much about them. Fix them up as well as you can, and enjoy them. If you can salvage the rheostats using vinegar and salt, do that rather than replace them, out of respect for their New England heritage. Otherwise, replace what you must replace, and then button them up - making sure that the gasket is good, or using mortite.
Which reminds me - you probably have the cloth surround woofers. Order sealant from RoyC, a member here who, it is acknowledged, has the best sealant for ARs and KLHs. If your surrounds are leaky, bass suffers.

 

[Nicholas M]

Possibly the most elegantly proportioned speaker I have ever seen. And it appears you have the plywood, rather than particle board cabinets which some people think sound better.
Even so, they are small two way speakers, so don't fret too much about them. Fix them up as well as you can, and enjoy them. If you can salvage the rheostats using vinegar and salt, do that rather than replace them, out of respect for their New England heritage. Otherwise, replace what you must replace, and then button them up - making sure that the gasket is good, or using mortite.
Which reminds me - you probably have the cloth surround woofers. Order sealant from RoyC, a member here who, it is acknowledged, has the best sealant for ARs and KLHs. If your surrounds are leaky, bass suffers.

wow great. Put me in touch with RoyC! Ive been looking for good quality dope.

 

[Nat]

He is a member here - you can PM him.

 

[Nicholas M]

Did that! I noticed the L pad only has to solder points whereas the old pots have 3. I'm curious as to whether I just resolder that extra Terminal 1 end to the end opposide the Terminal 2 / cross over ?

 

[Nat]

I'd be cautious about soldering terminals without being certain of what you are doing. I've simply cleaned and reused the original pots (I think), so can't offer guidance.