Jnkns Posted February 20, 2021 Report Share Posted February 20, 2021 Hey everyone! First post here. I've had this pair of AR-4x's for probably about 5 years now but rarely listened to them. My old house just didn't have a great spot to setup a listening area so most of my music consumption took place at my computer with my JBL near field mixing monitors or in my car on the way to work. I recently moved and have a better place for listening so it's time to make these old 4x's better. I've done some reading through a bunch of restoration threads here and there's a ton of great info! But also a ton of confusing info. I think I might have two of the older 4x's that share some features of the AR-4's. And mine have the big waxed box capacitor which was confusing the heck out of me when I was seeing the canister style caps in other peoples speakers and thinking "Mine doesn't have caps in it! What the huh?" Until I finally came across something explaining the waxed box thing was an older cap. Anyway, I'm just starting this thread to post some pics of my speakers and to document what I do with them and hopefully get some pointers from you all who know more than I do. I'm a total beginner in this world! First question: I know the tweeter level pots need to be swapped out. They've always been really crunchy and cut in and out. I just pulled the speakers apart for the first time and looked inside the pots and they are just totally shot...the wiper on the one I took apart has pretty much disintegrated. I've read that L-pads can be used as a replacement. Can anyone point me to a good source for them? But I've also read that L-pads can burn up really easily in there. Anyone have any insight on that? Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 20, 2021 Author Report Share Posted February 20, 2021 What do you all think of these? https://www.ebay.com/itm/AR-3-AR-3a-AR-2-AR-2ax-AR-4-AR-4x-AR-5-AR-6-wirewound-potentiometer-pot/153936403748?hash=item23d7531d24:g:wTMAAOSw2XdeIgUS&shqty=1&isGTR=1#shId Quote Link to comment Share on other sites More sharing options...
JKent Posted February 20, 2021 Report Share Posted February 20, 2021 Welcome to CSP! The AR-4x were my first speakers and my first restoration project. Yours look to be in good shape. L-pads are perfectly fine and about$5 each from PE. They do NOT burn up. Those pots on eBay are very nice but $30 each seems steep. If you can wait a couple of weeks I will be offering those same pots to CSP members for half the price: $30 a PAIR. I have them but am unable to handle the shipping yet due to recent surgery. If you are interested send me a PM Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 20, 2021 Author Report Share Posted February 20, 2021 Hey JKent! I tried to PM you but it shot back a message saying you can't receive messages. What's the story on the pots you have? I'm not in a huge rush and would like to get something as close to original as possible. Are the pots you have better than going the L-pad route? Quote Link to comment Share on other sites More sharing options...
JKent Posted February 20, 2021 Report Share Posted February 20, 2021 Maybe my in box was full. I just cleared it and also sent a PM to you. The pots are nice—exactly the same ones as on eBay. They are better than Ohmite or Soviet surplus because they have closed backs. But L-pads work just fine Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 21, 2021 Author Report Share Posted February 21, 2021 Got it! Sounds like a worthy upgrade. If I'm going to go through the trouble to get these back in operation I might as well do it as best I can. Quote Link to comment Share on other sites More sharing options...
genek Posted February 21, 2021 Report Share Posted February 21, 2021 On 2/20/2021 at 8:37 AM, JKent said: The pots are nice—exactly the same ones as on eBay. Any chance you could pry one of those open for photos? Would really like to see what the wiper looks like. Quote Link to comment Share on other sites More sharing options...
JKent Posted February 21, 2021 Report Share Posted February 21, 2021 Quote Link to comment Share on other sites More sharing options...
genek Posted February 21, 2021 Report Share Posted February 21, 2021 Looks at least a bit more substantial than the later AP units. Wonder how well they'll hold up over time. Quote Link to comment Share on other sites More sharing options...
JKent Posted February 21, 2021 Report Share Posted February 21, 2021 They seem very substantial—much heavier than the original AP units Quote Link to comment Share on other sites More sharing options...
RoyC Posted February 22, 2021 Report Share Posted February 22, 2021 They worked out well for an AR-3a restoration this past week. They are substantially heavier than the original pots. Roy Quote Link to comment Share on other sites More sharing options...
JKent Posted February 22, 2021 Report Share Posted February 22, 2021 I’ve put an ad in “For Sale”. Don’t want to hijack this thread Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 25, 2021 Author Report Share Posted February 25, 2021 From reading a bunch of AR-4X threads it seems I have the same crossover as Ra.Ra in this thread: I gather I will need a 20uf and a 24uf cap. I am very new to this and have fairly limited electronics knowledge...I can solder well, but I don't have a deep enough grasp of physics to be able to figure all of this out. What voltage? 250? Are these what I need? https://www.parts-express.com/Dayton-Audio-DMPC-20-20uF-250V-Polypropylene-Capacitor-027-436 and https://www.parts-express.com/Dayton-Audio-DMPC-25-25uF-250V-Polypropylene-Capacitor-027-438 Should I step up to the tighter tolerance versions? Should I chain some smaller value caps to a 20uf cap to make exactly 24uf instead of going with the single 25uf cap? Any help from those more knowledgeable would be much appreciated! And if anyone is able to explain the "why" of it all I love to learn and would be all ears. Quote Link to comment Share on other sites More sharing options...
JKent Posted February 25, 2021 Report Share Posted February 25, 2021 Interesting. I think you should check to be sure your speakers have the dual value 20/24uF caps AND that the 24 is wired into the circuit and not just left unused like Roy’s. But then yes—the caps you linked would be fine and no—you don’t need the tighter tolerance. If you order caps from PE I suggest you also get some of their foam gasket tape for the woofers Kent Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 25, 2021 Author Report Share Posted February 25, 2021 Here's a better pic of my crossover. It looks identical to Ra.Ra's. And the serial numbers are very close to his as well. Quote Link to comment Share on other sites More sharing options...
JKent Posted February 25, 2021 Report Share Posted February 25, 2021 Sure looks that way. I PM’d ra.ra and asked him to weigh in just to be sure Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 25, 2021 Author Report Share Posted February 25, 2021 54 minutes ago, JKent said: Sure looks that way. I PM’d ra.ra and asked him to weigh in just to be sure Thanks for all your help thus far, sir! Much appreciated. Quote Link to comment Share on other sites More sharing options...
RoyC Posted February 26, 2021 Report Share Posted February 26, 2021 Jnkns, Your specimens are very early versions of the 4x. The crossovers are original to this version, with a 20uf capacitor in series with the tweeter and a 24uf capacitor in parallel with the woofer. I've drawn on your photo to help clarify the circuit. The bracket holding down the dual 20uf/24uf capacitor is actually part of the circuit. see below... I noticed the pot in your photo has been re-wired to by-pass the wiper. One of 2 green wires formerly connected to the #1 terminal has been cut and soldered to the #2 terminal. It is very important to correct this when you install the new level controls! (Btw, The new pots Kent is offering are a great choice for the price.) Roy Quote Link to comment Share on other sites More sharing options...
Jnkns Posted February 26, 2021 Author Report Share Posted February 26, 2021 Roy, That is immensely helpful, thank you! I'm sure I'll be asking you to check my work once I get started on it. I have a set of pots from Kent arriving in the next day or two, and a handful of things from Parts Express too, as long as USPS doesn't disappear them. Haha. Quote Link to comment Share on other sites More sharing options...
Jnkns Posted March 8, 2021 Author Report Share Posted March 8, 2021 On 2/25/2021 at 9:41 PM, RoyC said: I noticed the pot in your photo has been re-wired to by-pass the wiper. One of 2 green wires formerly connected to the #1 terminal has been cut and soldered to the #2 terminal. It is very important to correct this when you install the new level controls! (Btw, The new pots Kent is offering are a great choice for the price.) Roy I finally have everything together to start digging into this project. Roy, can you clarify something for me? You said the green wire going to pot terminal 2 in my picture should be going to pot terminal 1 instead. But if I'm reading the schematic in Ra.Ra's thread correctly (and I VERY well may not be) it looks like the green wire coming from speaker terminal 1 should connect to terminal 1 on the pot, the green wire from the tweeter should connect to B on the pot, and the yellow wire from the tweeter along with the green wire coming from the 20uf resistor should be going to terminal 2 on the pot. Is this schematic incorrect? Or am I reading it wrong? Quote Link to comment Share on other sites More sharing options...
RoyC Posted March 8, 2021 Report Share Posted March 8, 2021 Good catch, Jnkns. I saw the snipped green wire soldered to the #1 pot terminal and assumed it was a by-pass, as this terminal is typically connected to the capacitor in other AR models. The schematic is correct for your version of the 4x, so disregard my red "X" and drawn green line on your photo. Are your other speaker's connections the same? What type of level control have you chosen? Quote Link to comment Share on other sites More sharing options...
Jnkns Posted March 8, 2021 Author Report Share Posted March 8, 2021 Yay! I read a schematic correctly! Haha. I have heard of people soldering on a jumper to bypass a defective pot though, so your note was understandable. Yes, the other one was wired the same. Pic of the other one is attached. Somebody did a real hack job on the soldering in these. Tonight I desoldered the woofers and clipped all the wires going to the pot connections so I could remove the old pots and install the new ones I bought from JKent. I got those installed and soldered the B terminal connection because I was fairly confident I knew what needed to go there. I also cleaned up most of the old black goop that sealed the woofer to the cabinet. I'll be replacing it with foam gasket. That black stuff is a pain to remove. Some of it peels out in nice strips but some of it really doesn't like to let go. Hopefully sometime this week I'll have time to continue working on it. I may take a picture and draw out a wiring diagram to clarify things for myself and ask you to double check it for me, if you don't mind. It could be a helpful addition to this thread for someone searching for info in the future too. Quote Link to comment Share on other sites More sharing options...
RoyC Posted March 8, 2021 Report Share Posted March 8, 2021 That really is some nasty solder work. Those speakers did not leave the factory that way! Other than some discussion here in the forum I have not worked on a pair of 4x's with your crossover. The closest I've come was a pair with only the 20uf half of the dual capacitor in use. The other half was never connected. I will be interested in your experience with the new pots. Quote Link to comment Share on other sites More sharing options...
giovanni56 Posted March 8, 2021 Report Share Posted March 8, 2021 On 26/2/2021 at 03:41, RoyC said: Jnkns, I tuoi esemplari sono le primissime versioni del 4x. I crossover sono originali di questa versione, con un condensatore da 20uf in serie al tweeter e un condensatore da 24uf in parallelo al woofer. Ho disegnato sulla tua foto per aiutare a chiarire il circuito. La staffa che tiene premuto il doppio condensatore da 20 uf / 24 uf fa effettivamente parte del circuito. vedi sotto... Ho notato che la pentola nella tua foto è stata ricablata per bypassare il tergicristallo. Uno dei 2 fili verdi precedentemente collegati al terminale n. 1 è stato tagliato e saldato al terminale n. 2. È molto importante correggere questo problema quando installi i nuovi controlli di livello! (A proposito, i nuovi vasi che Kent offre sono un'ottima scelta per il prezzo.) Roy I'd be curious to measure the R of the bracket that's part of the filter wiring, which is under the woofer's low pass inductance Quote Link to comment Share on other sites More sharing options...
Jnkns Posted March 9, 2021 Author Report Share Posted March 9, 2021 giovanni, I'll try to measure it for you while I have things taken apart. Quote Link to comment Share on other sites More sharing options...
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