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ar_pro

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About ar_pro

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  1. I really like the Stereo 70 in stock condition, but with a diode replacement for the selenium rectifier. Years ago, I did a conservative modernization of a rusty ST-70 from the late '50s that included re-plating the chassis, and powder-coating the cage and transformer housings. The original phenolic board was replaced with a very nice fiberglass type that was identical, so that I could keep the 7199 driver tubes. Everything was wired exactly according to the manual, but with teflon wire, modern sockets & switches and tighter-spec resistors and caps. As I recall, noise and hum were very low after the rebuild, and there was plenty of punch for a 35 watt/channel amplifier. There are many well-regarded mods for the ST-70, and all sorts of upgraded parts available, so there are lots of options.
  2. Unmodified AR-5 speakers are very desirable, and my inclination would be to keep them as close to that condition as possible, and have the tweeters rebuilt. It's not simply about frequency extension, the dispersion characteristic of the Classic Era tweeters had a lot to do with their success. The NAD preamp would be a nice combination with a refreshed Stereo 70. Are you doing a stock restoration?
  3. (Thinking hard) I believe that there are screws beneath the vinyl decal on the plastic trim piece.
  4. Those look like they're in great shape. $40 might qualify as the buy of the year - well done! The Acoustic Blanket is difficult to remove without damage, since the entire surface is attached to the cabinet with double-faced adhesive. If you're feeling lucky, maybe try that heat gun?
  5. We're down to a single pair of AR speakers, which is something that I haven't been able to say in a long time! So, it's AR-91 guts in AR-3a cabinets, powered by a Mac MA-6900 with a Technics 1210 with SME arm and Shure cartridge. A very satisfying, quirk-free setup for enjoying vinyl. 😉
  6. Absolutely - speak with your seller first! The 300 was a unique product - a great-sounding low-powered receiver from the era when major manufacturers were waging wattage wars. My wife had one of these in college, matched with a set of Large Advent speakers, and a Thorens turntable; it was a fine little system for not very much money.
  7. No problems specifically with the Model 300, but RF leaking into audio stages is something that used to be not uncommon. Your first instinct to consider the possibility of an unauthorized broadcast is a good one; way back in the '70s, RF interference was usually someone in the area with a beefed-up CB radio, but now it could be anyone running a linear amplifier in a pirate setup. Has the station used call letters or announced a frequency? Try checking the broadcast with an AM/FM portable to see if they're for real. Also, try sliding your tape monitor switch back & forth, just to be certain of good contact, as RF loves to enter through switches. If no luck, try contacting one of the many Ham radio websites & forums, since those guys have a ton of experience, and love solving issues like this.
  8. Robert - You could contact Bill Legall at Millersound: (215) 412-7700 He has undoubtedly seen this sort of thing before, and could best advise you regarding repair or replacement. If you have the original woofers, maybe it's just a question of installing the proper surround, and maybe a new VC.
  9. Are you asking if you can use an AR-1 on one channel of a Sony receiver, and an AR-2 on the other channel? The short answer would be "yes", but the combination wouldn't be ideal for a few reasons. An AR-1 in working, unmodified original condition is worth a little bit of money; the Altec 755A driver alone is selling for close to $2,000, so you might want to investigate this before doing anything to the speaker.
  10. There are many threads on this issue. If your goal is to achieve the best price in a sale, the rule of thumb is to do nothing, since anyone willing to pay top dollar would be seeking the most original version of the speaker possible. This would preclude attempting any amateur repair work on the 755A - you'd most likely be selling to an expert who would probably prefer to do their own restoration, or have the driver repaired by a known craftsman. As Aadams has written, the only replacement would be another cast-frame woofer from an AR-1, AR-1W, or AR-3.
  11. That's good information on the Erse electrolytics, especially if you're working on a nice speaker. This guy tore down a Pulse X capacitor: https://community.klipsch.com/index.php?/topic/178770-erse-pulse-x-capacitors/
  12. The replacement car stereo woofers won't be the same as the original AR drivers. As per AR55's information, you'd need a pair of the 200035 or 210035 (Tonegen) 8" woofers to bring everything to spec. There is a pair of "tested & working" 200035 woofers currently on eBay, at about $100/each. Don't fret over the crossover - this sort of soldering is very easy, and you could teach yourself how-to with a YouTube video with maybe an hour's practice. If you did any work on the crossover, it would just be to replace three small capacitors, as everything else should still be just fine. Prior to painting or doing any crossover work, it would be a good idea to remove the polyfill stuffing into a pair of trash bags. Wear a mask, as it will put particles in the air. Here's a link to an AR-93 restoration page, with helpful photos & schematics: https://www.audiovintage.fr/leforum/viewtopic.php?f=20&t=59580
  13. The visible woofer and the tweeter in the foremost enclosure are not AR drivers. The two 8" midrange drivers appear to be original. The cabinet material is a type of particle board, so it won't really sand, as you've described. It was originally painted a matte black, so you could do that again, using a good primer for its adherence quality. The drivers should be removed before you do any cabinet work, and you'll also be able to get a good look at the crossover, and replace any capacitors as needed. Plenty of members can help you with crossover advice. Once the drivers are out, take some photos, including any printed part numbers, so we'll know what you're working with. Good luck!
  14. The ADI-2 DAC looks like a terrific piece of equipment, with an extraordinary number of useful features. This is a little off-topic, but have you tried it with headphones yet?
  15. That's some useful practical information, lakecat - thanks. Many years ago, I owned a 2205, which drove a pair of early AR-9 speakers; the performance was excellent, and it was a great combination - almost as if the two had been made for each other. I'd imagine that the MC2205 and the LST would also be a perfect pairing.
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