RoyC Posted March 16, 2019 Report Share Posted March 16, 2019 3 hours ago, lARrybody said: To me (my opinion) L-pads are not appropriate and rebuilt original Aetna-Pollak pots are just asking for future problems. When AR re-introduced the AR-3a as the "AR-3a Limited" in the late 80's/early 90's, 15 watt L-pads were used as the level controls. AR sold 15 watt potentiometers, and later, 15 watt 8 ohm L-pads as pot replacements into the 90's. It should also be noted that despite the L-pad scare tactics in his listing, Captain Fantastic is selling ordinary L-pads as well. While I have no reason to believe his AR replacement controls are anything less than satisfactory, L-pads remain a perfectly acceptable and cost effective option. The only burned/melted controls I have seen in AR speakers over the past 40 years have been a handful of original AP pots. I agree most original pots are not worth the refurbishment effort today. I toss approximately 75% of the original pots I pull these days. Roy Link to comment Share on other sites More sharing options...
JKent Posted March 16, 2019 Report Share Posted March 16, 2019 4 hours ago, lARrybody said: I wish I knew where Captain Fantastic sourced these potentometers. I will give them two thumbs up. I thought maybe he cobbled them together himself. There are photos of the innerds on the ebay listing and they look like coils recycled from old A-P pots. The ad states "I decided to re-manufacture original wirewound controls that were used back in the days." They do look nice on the outside. Link to comment Share on other sites More sharing options...
fran604g Posted March 16, 2019 Author Report Share Posted March 16, 2019 15 hours ago, lARrybody said: I used a set of four on some AR5's that had been redone 2 years ago with L-pads on the tweeters and Ohmites on the midranges. Like Ra.Ra. stated the build quality is fantastic. My testing with a ohmmeter shows that the range is spot on and smooth. They are a little bit stiffer than the RHS15RE and don't have the flat shaft end, but these differences turned out to be of no consequence . I wish I had opened one up and looked inside, but it is like the old adage "if it's not broke". I have a set of super nice early 3a's to do this summer and I am debating getting another set or using a set of Ohmites I have stashed away. To me (my opinion) L-pads are not appropriate and rebuilt original Aetna-Pollak pots are just asking for future problems. I wish I knew where Captain Fantastic sourced these potentometers. I will give them two thumbs up. Thank you! I can't wait to have my 3a's back in their system. It's hard to miss them with 604-8Gs in the house, but the 2 sound so differently that I would seriously miss either pair if they were to suddenly disappear. Link to comment Share on other sites More sharing options...
fran604g Posted March 23, 2019 Author Report Share Posted March 23, 2019 I measured the tweeter on SN 45696 at 1.0 ohm. The other speaker's (SN 3A-04125) tweeter is 3.3 (corrected reading - got a false reading earlier) ohms, thankfully - but obviously it's time to have the failed one rebuilt by @Chris1this1. Looks like this rebuild's going to take a little longer than I had hoped. ☹️ Link to comment Share on other sites More sharing options...
fran604g Posted March 24, 2019 Author Report Share Posted March 24, 2019 A couple of notes regarding these new pots (see pics below): 1.) You won't be able to reuse the original rheostat rubber sealing gaskets, as the mounting thread of the housing is much shorter than the originals, and the thread will not protrude sufficiently for the nut to engage the thread. 2.) Even without the rubber sealing gasket, the tab is too long and needs to be cut down before mounting or you run the risk of striping the single thread that engages with the nut when trying to mount the new pot. The nut is steel, the thread is aluminum. I would think once the tab is either cut down in length or bent down flat, and they're tightened securely, they should provide an acceptably air tight seal? I'm thinking of using a little silicone caulk just to be certain there's an airtight seal. 3.) The new pots are obviously much larger than the originals, so they'll be a little tighter fit in the original locations. I needed to reposition the solder tabs mounted to post "1" a little so that they wouldn't contact the pot's metal housing. Nothing that complicated, for sure, but I just thought everyone should know. Fran Link to comment Share on other sites More sharing options...
fran604g Posted March 24, 2019 Author Report Share Posted March 24, 2019 I finished the new rheostat installation on SN 45696 today. I bent the "locking" tabs on them to ~45°, so that I could start to thread the nut onto the pots without trying to pull the tab into the melamine, and risk striping the thread with the first couple of rotations. I'm confident the pots will not rotate on the melamine once they're fully tightened. The new pots came with crimp-on connectors for the wiring, which is probably fine, but I elected to crimp them and solder them - with the exception of 1 connection on each pot: the "B". Instead, I tinned the tab used for the fastener, and soldered the 2 driver's wires directly to the tab. This went marvelously. Photos for posterity: Link to comment Share on other sites More sharing options...
fran604g Posted March 25, 2019 Author Report Share Posted March 25, 2019 The Hi pot measures okay, but the Mid is all over the place. I popped the backs off to illustrate the degradation after 6-1/2 years of use. Actually, they started screwing up more than 2 years ago, but there were still "sweet spots" I could set them and leave them. About a year ago I noticed SN 45696 was missing the Hi end. Another photo for posterity: Link to comment Share on other sites More sharing options...
fran604g Posted March 25, 2019 Author Report Share Posted March 25, 2019 Tackled the other crossover pots this AM (#3A-04125). The originals were measuring all over the place. After looking hard at the woofer inductor, I realized it's definitely smaller than the factory marked #9 in the other unit. Is it still possible that it's a number 9? Do any of you guys have the physical measurements for a later #9 inductor? Mine is 2-1/8" OD x 1-1/32" tall. I suspect it may be a #7 that was left in the cabinet whenever the unit was upgraded with the new tweet and mid. That would mean the woofer was apparently also swapped, right? I think someone told me in 2012 that the cabinet is consistent with an older build, suggesting the unit may have began life as a AR3. I personally believe whoever owned these, started out with a single 3, and later on when he bought an additional single AR3a, he upgraded the 3 to match for a stereo. At least that sounded feasible in 2012, who knows? They came out of a local estate sale of a nice well maintained home, so the hypothesis makes sense. At any rate, what do y'all think about this woofer inductor? Link to comment Share on other sites More sharing options...
RoyC Posted March 25, 2019 Report Share Posted March 25, 2019 1 hour ago, fran604g said: At any rate, what do y'all think about this woofer inductor? Based on the cabinet serial number, and the original appearance of the installation, the woofer inductor is likely to be the #7/1.88mh version originally used with the cloth surround/alnico magnet woofer. If so, it is not appropriate for your foam surround/ferrite magnet woofer. You can add a 1.0mh inductor (after measuring the original to verify its value) in series with the original inductor, or replace it with a #9/2.85mh. You could try measuring the center hole, diameter, and height of the coil (not the plastic spool) to see if it matches your #9 coil in your other cabinet. It is best, however, to use a meter to measure the coil's value. Roy Link to comment Share on other sites More sharing options...
fran604g Posted March 25, 2019 Author Report Share Posted March 25, 2019 13 minutes ago, RoyC said: Based on the cabinet serial number, and the original appearance of the installation, the woofer inductor is likely to be the #7/1.88mh version originally used with the cloth surround/alnico magnet woofer. If so, it is not appropriate for your foam surround/ferrite magnet woofer. You can add a 1.0mh inductor (after measuring the original to verify its value) in series with the original inductor, or replace it with a #9/2.85mh. You could try measuring the diameter and height of the coil (not the plastic spool) to see if it matches your #9 coil in your other cabinet. Roy Thanks Roy, I did measure only the wire of both, and there's a significant difference in size. I'll come up with an LCR meter and measure to confirm, then see if I can find an original #9, or add additional inductance as necessary. I'm a little surprised this wasn't caught in 2012. Best regards, Fran Link to comment Share on other sites More sharing options...
RoyC Posted March 25, 2019 Report Share Posted March 25, 2019 15 minutes ago, fran604g said: I'm a little surprised this wasn't caught in 2012. Best regards, Fran Hi Fran, Just read back through this old thread. On Sept 18, 2012 I posted: "Btw, your 3a-04125 specimen would have originally been equipped with a cloth surround woofer. Unless someone switched it out along the way, that cabinet has the smaller #7 (1.88mh) inductor in the crossover. The #9 (2.85mh) inductor should be used with the foam surround woofer....and, yes, there is an audible difference. This is a bigger issue from a practical and historical perspective than the pot tabs." Roy Link to comment Share on other sites More sharing options...
fran604g Posted March 25, 2019 Author Report Share Posted March 25, 2019 Well, I'm eating crow! Sorry that I didn't grasp exactly what that meant then. Dear lord, do I feel dumb now. Thank you Roy, for setting me straight, I truly appreciate the help. Best regards, Fran Link to comment Share on other sites More sharing options...
RoyC Posted March 25, 2019 Report Share Posted March 25, 2019 2 hours ago, fran604g said: Well, I'm eating crow! Sorry that I didn't grasp exactly what that meant then. Dear lord, do I feel dumb now. Thank you Roy, for setting me straight, I truly appreciate the help. Best regards, Fran No problem, Fran...This stuff can be overwhelming if you are not doing it on a regular basis. If you need an inductor I'm sure I can help you out. Roy Link to comment Share on other sites More sharing options...
fran604g Posted March 25, 2019 Author Report Share Posted March 25, 2019 That would be great, Roy. I'm committed to getting these right this time, once and for all. Would you prefer we conduct this privately? Fran Link to comment Share on other sites More sharing options...
RoyC Posted March 26, 2019 Report Share Posted March 26, 2019 4 hours ago, fran604g said: That would be great, Roy. I'm committed to getting these right this time, once and for all. Would you prefer we conduct this privately? Fran Sure, send me a PM... Link to comment Share on other sites More sharing options...
fran604g Posted March 28, 2019 Author Report Share Posted March 28, 2019 I broke down and finally bought a cheap LCR meter. I should've done this years ago! Could've used one for my last amp rebuild. But, hey - better late than never I guess, and I'll have it for the upcoming amp rebuild. Sure as Roy said, the woofer coil in 3A-04125 is the incorrect #7; I believe it was leftover from the presumed factory update. The markings on it are mine for future reference - there were none. Link to comment Share on other sites More sharing options...
fran604g Posted April 1, 2019 Author Report Share Posted April 1, 2019 A quick update: I received the correct #9 woofer inductor from Roy, and installed it earlier. Onward! Link to comment Share on other sites More sharing options...
fran604g Posted April 6, 2019 Author Report Share Posted April 6, 2019 Hiya folks, This morning I got my tweeters back from Chris and just finished up putting the 3a's back together. Took em for a spin, and I'm truly stunned at the results! They've never sounded as good to me as they do right now! I'm a very happy camper. Despite them not being a "matched" pair - and years apart in production, with factory upgraded drivers in one of them, you'd never know! I'm completely in love with them again for the first time. My sincere thanks to Chris and Roy for their indispensable help in the resurrection of these iconic speakers! Cheers ya'll, Fran Link to comment Share on other sites More sharing options...
fran604g Posted April 7, 2019 Author Report Share Posted April 7, 2019 I did a quick white noise RTA with my Android just to "see" how they are performing. The red line was max. hold. Link to comment Share on other sites More sharing options...
fran604g Posted April 8, 2019 Author Report Share Posted April 8, 2019 I took another reading, because of the bump around 130 Hz. We have a bump in the road out in front of my house, and as we're a state route, trucks frequently bounce Right. In. Front. Of. My. Audio. Room. At any rate, I conducted another reading with white noise, and the bump disappeared. Thankfully! Tested with both pots @ factory "dot" positions. Link to comment Share on other sites More sharing options...
Aadams Posted April 8, 2019 Report Share Posted April 8, 2019 1 hour ago, fran604g said: t any rate, I conducted another reading with white noise, and the bump disappeared. Thankfully! Is this from your usual listening postion? Can you share the speaker placement particulars. For example relation to walls, corners, floors etc. Adams Link to comment Share on other sites More sharing options...
fran604g Posted April 8, 2019 Author Report Share Posted April 8, 2019 It was taken from my listening chair. Centered between them at 6 ft. to my ears, with them 6 feet apart each other. My audio room is something that might cause apoplexy from the serious listener though, so be forewarned. I move all the antique phonos out of the room when I really want to do some critical listening. I'll say this: they're perfectly balanced, the soundstage is wide and deep, and they image like crazy! I've been playing both my digital files, and vinyl. Vinyl really shines, but I'm not missing anything with digital either. Soundsmith Otello, DUAL 1229, Adcom GFP-710, TAD 60 w/ 6550 Tung-Sol reissues. The front end digital isn't anything special: custom built PC running win10, JRiver into the GFP-710, etc. Very near field, obviously. But, it all suits me. Link to comment Share on other sites More sharing options...
Aadams Posted April 8, 2019 Report Share Posted April 8, 2019 27 minutes ago, fran604g said: his: they're perfectly balanced, the soundstage is wide and deep, and they image like crazy! Not surprised. I asked because I suspected they were out in the room from this curve. How are you connecting w10 to the preamp? Link to comment Share on other sites More sharing options...
fran604g Posted April 8, 2019 Author Report Share Posted April 8, 2019 6 minutes ago, Aadams said: Not surprised. I asked because I suspected they were out in the room from this curve. How are you connecting w10 to the preamp? Creative Audigy Rx SB card, mini out to RCA interconnect. Link to comment Share on other sites More sharing options...
fran604g Posted April 9, 2019 Author Report Share Posted April 9, 2019 I know the "numbers" don't lie, but for the record I think the low end is right where my ears like it to be. I really wouldn't want to add any more bass to the equation. These speakers can really pump out the the low end - as we all know. Maybe it's because I've taylored my sound systems to my own preference for so long that I can instantly dial it in for me. I also noticed when playing Bela Fleck and the Flecktones - "Flight of the Cosmic Hippo" (a very bass-heavy tune) that I was seeing signals below 40Hz registering in the same -50 /-75 range. Keep in mind I am NOT an expert with RTA/Spectrum Analyzer territory by any means. I'm just poking around in the dark here. BTW, there was no enhancement made to the digital signal with JRiver - any and all DSP features were disabled except for their recommended "Output Format" (No Change, and JRSS Mixing), and "Volume Leveling" (Album Based, and Clip Protection) features. Honestly - this time around - I haven't noticed anything negative. In 2012, I was surprised by their sound, but not nearly as impressed as I am today. The correct inductor, professionally restored tweeters, new rheostats, and some real diligence on my part (a very difficult task for those of us who are ADHD!) this time, has paid off in spades! Thanks again for everyone's help putting my iconic and much appreciated 3a's back in order. Link to comment Share on other sites More sharing options...
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