ADS L400 Crossover Problems?

[Zach K]

Hello all, I recently bought a pair of ADS L400 Speakers at a local thrift store (the rounded corners/metal ill type). One speaker sounds great. The other speaker also sounds pretty good but has almost no sound from the tweeter. I swapped the speakers and there was no change. I even acquired a replacement tweeter and installed it (wow the old tweeter was really hard to get out!!) and there is still the same issue, leading me to believe it is a crossover problem.

I've attached a pic of the crossover. I have some basic soldering experience so I'd be willing to attempt to replace the crossover components but I can't determine what is what and I'm not even sure how to remove them from the board (I tried and failed to make any headway with the solder with my radioshack soldering iron). I was wondering if anyone had any advice or suggestions. Even better would be a referral to someone in NYC area that could rebuild the crossovers with newer components. Thanks!

 

[chigger]

They usually last long time , I would just change the black one , I have the L810s , also check the wires , should be good they use silver wire

 

[ra.ra]

Hard to tell what might be going on here, but if you've tried several tweeters in the problematic cabinet with no resultant change, it does sound like a crossover component just might require replacement.

The attached chart from 1982 is the only document I have which might help, and it shows the conceptual crossover schematic for a variety of two-way speaker products. For the 400 model, it shows five components, consistent with your pic. ( I don't know what the final two columns are about - - these are titled R, subscript e1; and R, subscript e2). It appears to me that in your crossover, the black cap (C1 - 25 uF), the black coil (L1 - 1.0mh), and the tan resistor (R1 - 2.5 ohms) are associated with the woofer. The tweeter components appear to be the green coil (L2 - .47mh) and the blue cap (C2 - 6.8uF).

Take a close look and see if this info is consistent with your speaker's crossover. ADS generally used very good quality components in their crossovers, and while somewhat unusual, I suppose it is possible that the blue film cap is in need of replacement.

 

[L200B]

Nothing wrong with radio shack soldering iron. Solder sucker will change your life.

 

[jdurbin1]

The 400 in that crossover chart is not the same model as the L400 described above.

You need to check continuity from input to tweeter on both sides of the circuit. When you get to the capacitor (the blue film cap), you won't be able to measure continuity but if you hook another small value non-polar cap in parallel to that one and nothing changes, the film cap probably isn't the issue. Jumpering the resistor should tell you if it's causing the problem.

John

 

[ra.ra]

jdurbin is correct about the speaker models. In pic attached, model L400 is on left; model 400 is on right.

Sorry about that ....... was just trying to help. (grumble, grumble..... damn nomenclature.....too confusing....grrrr.)

 

[dc270]

You might look into solder braid or wick- it is a spool of braided wire, when after you lay it on a solder joint then press the iron on top of the braid it actually sucks up the solder into the braid, like a wick. Works great!
C/O your old caps with updated 5% Dayton polys from Parts Express-done!
DC