JKent

Thanks for the positive comments. I like the black too. Sorry but I only took 1 shot of 1 cap. There's a pic here of the innerds: http://www.davidreaton.com/advent_model_400_fm_only_radio.htm I'll be doing another and will be sure to take pictures! You're right about the knobs, and especially painted black the 400 is sort of a "mini 300." Ah... the 201 cassette deck! Here's a page: http://www.davidreaton.com/Cassette_Decks.htm Back in the day (about 1970 or so) I bought my first tape deck. Advent had revolutionized the industry by adding Dolby and Chromium Dioxide tapes to what had previously been suitable only for dictation or other lo-fi applications. The 201 was a Wollensak unit widely used in schools (where they had to stand up to abuse), modified with the addition of the Dolby circuitry and CrO2 bias. At the time Advent and Wollensak marketed identical units (except for different knobs, meters and logos) but unlike Advent, Wollensak could be had at a discount. -Kent

The Advent 400, for those who may not know, is a terrific FM-only radio from Henry Kloss after he left KLH. It is solid state of course but reminiscent of Kloss's first radio--the KLH Model Eight which featured an FM receiver with his signature vernier tuning dial in one box and a separate acoustic suspension speaker. Like all Kloss radios, the Advent 400 is known for its excellent reception. I've owned about a half dozen of these and they're impressive. The 5.25" full-range driver is the biggest of any Kloss radio and at some point they apparently used the famous Phillips whizzer-cone driver (but those are rare). According to Fred Pinkerton, Audio Product Manager for Advent, the 400 cost over $90 to produce although they sold it to dealers for under $110 and it had an MSRP of $125 (no wonder they went bankrupt). The tuner section, according to the Owner's Manual, "uses techniques and parts . . . associated with far more expensive receivers." Unfortunately, the cabinets are white polystyrene plastic that turns yellow with exposure to UV rays. The only way to restore the white is a painstaking process of sanding and polishing. One ebay seller paints them white but I was never a fan of the painted look or the possibility of scratching. YMMV. Another issue with these is low volume. Apparently some of the capacitors used--10uF axial leaded ones in the amp section--are known to fail. So.... this particular 400 worked but the volume was very low and the cabinets were just awful. I asked my favorite tech about the volume issue. I didn't want to take the radio to him because the repair would cost more than the radio is worth. He alerted me to the axial cap issue and implicated some other possible culprits. Also got some help over on AK. I replaced the four 10uF 16V axial caps with 10/25 radials (they had to be bent over to clear the pots) but there was no improvement (btw they all measured ~14uF). Went back in and found a 10/16 radial and pulled that. It read open! Bingo! Problem solved. Just to be safe though I replaced all the electrolytics on the amp board. Put it back together and it now plays LOUD! btw, all the 'lytics were about 40% out of spec. Maybe should have done the FM board as well. I did not replace the 1000uF 35v filter cap. It's a Rubycon and the radio doesn't hum so I left it. Couldn't measure that value with my cheap LCR meter. As for the cabinets, I've written before about using truck bed liner on old CSW speakers with the Nextel finish http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7315 Thought I'd try that. It's truck bed liner, so it's rugged and there shouldn't be a problem with scratching. Results shown below. That's a before shot of the same radio--yuck! Not a "restoration" but these radios don't have that much collectible value. IMHO the pebbled black finish looks good. Also replaced the power cord for 2 reasons: I can use the original white cord on a KLH Model Eight restoration, and the black cord looks better with the black cabinet. -Kent edit: 2nd photo is new, showing truck bed finish

Thanks Robert Yes--the xo boards came out simply, fastened with just 4 screws and no adhesive. Here's a source for your grilles: http://www.foamspeakergrilles.com/ The L100s are legendary--a worthy project. Here's a brief write-up http://www.vintage-speaker-review.com/2012/02/jbl-l-100.html Good luck and be sure to post pics! -Kent

Nice work Carl. I suppose we're getting into the "mods" area now but have you looked at the 12" Mavin EM-TL3006Y-8 Woofer? They claim it's a drop-in replacement for the Large Advents. All the T/S parameters are shown on their website but it's mostly Greek to me I know the OLA Advent woofer was 10" in a 12" frame but wonder if this (or any) 12" would give the bass extension you say the Madisound/SS replacement lacked. The sales pitch on their site says "Proven and tested, it sounds just as good, if not better than the original Advent drivers. Over all still a very good sounding speaker, much like we remember, with a bit more low end punch". -Kent

Follow-up: Very nice, with good build quality but they won't be replacing my ARs. They seem quite bright, even to my old ears. Found a write-up here, which is pretty consistent with my observations: http://www.audiokarma.org/forums/showthread.php?t=134980 AK member thedelihaus wrote; "I loved them for this. Drum and bass, techno, hip-hop, heavy metal, and many other flavours of music are embraced by these dynamos. But put them on a diet of jazz, or female vocals, or male vocals, acoustic, or folk, and the JBLs are not my cup of tea." Since I never listen to techno, hip-hop or heavy metal I can't comment on that but I agree these do not excel with the music I listen to most: Jazz, "classic" rock, acoustic and classical. The AR-3a OTOH does very well with all of those. The JBLs are very very nice but as thedelihaus wrote, just not "my cup of tea." YMMV -Kent

NOT "Classic New England Speakers" I know but I haven't gone over to the Dark Side A friend's brother asked if I could repair them because "the woofer on one of them blew out." I figured it was the surround and told him to send them my way. I'd never worked on JBLs before and found some surprises: They're nice looking, with real walnut veneer. The tweeter is covered with a mesh dome. Woofers are very substantial cast aluminum frames. Nice. Ported of course. Dimensions are 20.5" x 12.5" x 10.5". Smaller than an AR-2ax, about the size of a Dynaco A-25. The L46 appears in a 1982 JBL brochure. Because the NPE capacitors are over 30 years old I decided to replace them with film. Each xo has two 14uF caps and one 7uF. In addition there are 0.0038 film bypass caps on 2 of the NPEs (according to the brochure; "The network makes use of polypropylene bypass capacitors for better resolution of complex transient waveforms, and therefore clearer, more accurate sound." I doubt it but I left the bypass caps in place. YMMV). I replaced the NPEs with caps I had on hand: A Madisound "surplus" 10uF + two "surplus" 2uF caps for one of the 14s, a 10uF surplus plus a Dayton 4uF for the other and a Carli 6.8uF + a Nichicon 0.2 for the 7. Side note: I really like the surplus 10uF caps but the surplus 2uF caps have maddeningly short leads! No mistaking polarity on JBL drivers. The + terminal is male and the - is female (or maybe the other way around, but you can't make a mistake!). Got new surrounds from John at MSound. He's no longer on ebay but can be reached at msound@shentel.net. Also bought new dust caps and the "trim" external gaskets. The surrounds are rear-mounted to the cones. I'd encountered that before with Advents and it wasn't too difficult. I did try front-mounting first but it just looks better rear-mounted with the white cones (again from the brochure "the woofer cone is coated with Aquaplas, an exclusive formulation which creates a laminated construction with ideal damping characteristics"). First surprise: TWO dust caps! Roy said this is not unique but I'd never seen it before. I cut the inner cap and hinged it back for shimming, then glued it back in place when finished. The outer dust caps I ordered were the same diameter as the originals, which was a mistake on my part but I just trimmed the originals as close as possible, glued the new ones on and later filled in around the flange with white glue to give a smooth transition. Roy says all those clamps were not needed. Makes sense. I was just following some old MSound instructions but the glue (Aleene's Tacky) really grabs well. The cabinets had been well taken care of but there were a couple of whitish scuff marks and the wood was kind of dry so I first wiped them down with Howard Restore-a-Finish, rubbing the white marks with some steel wool. The next day I applied a coat of Minwax Antique Oil followed by a second coat the following day. Put them back together and fired one up. UGH! Is this the "West Coast sound?" All bass an no highs. Oh wait--time to get out the ol' stethoscope and listen to the tweeter. Duh. Dead tweeter. I pulled it out and did a couple of tests to be sure. Yup. One good tweet, one bad. These tweeters can be rebuilt but JBL no longer has the diaphragms and after-market ones from Simply Speakers are $25 so I just bought a second-hand JBL 034 tweeter on ebay. NOW let's give a listen. Very nice. I have not done an A/B comparison with my AR-3a's but these are nice speakers (when the tweeters are working) Total cost of the restoration was about $70. Not bad. A few pics attached. -Kent

Cizek made a matching subwoofer (the KA-18). I have never seen one "in the flesh" but found a photo on google http://www.audiocostruzioni.com/r_s/diffusori/diffusori-2/cizek-satelliti-sub/cizek.htm Fantastic! Looks like these are in Italy. Maybe Paolo has seen and heard them. Speaking of the KA-1. I saw some on ebay but was too late to buy. Good thing! These "Cizek KA-1" speakers were KA-1 cabinets with who-knows-what inside. And they're ported! Sacrilege Here are 2 photos: My (real) KA-1s and the impostors. -Kent

Pete, I think the new thread was a good idea. These long threads get a little disorganized. So I'm not going to go muck up your pristine new thread, but wanted to post a comment: I built the 4.7K version some time back, but did not keep the OLAs for long. To my ears they did not measure up to the AR-2ax's I was using at the time. But I do use it. It's in an External Processor loop so it can be easily switched in and out. What I find is that some recordings seem to benefit from the BSC while others sound better without. The current speakers are AR-3a with MicroStatic supertweeters and a VMPS sub (crossed over at 30Hz). Source is usually a Tivoli CD player. Other equipment includes DB Systems pre-amp and tone controls, an AR-SRC remote (that's where the EPL is) and an Adcom 555/II power amp. I haven't kept careful track of when the BSC is in or out of the system but IIRC I usually keep it out for classical and jazz recordings but switch it in for "some" rock or popular recordings. Does that make sense? Anyway, it's a fun little gadget. -Kent

Update: Dan at Akitika (it's a palindrome) has just announced the release of his preamp kit. I have not built it but it looks like a winner. Sort of a 21st century PAT-4. It has a remote and expansion panels for future additions and improvements. Not much is made in the USA anymore, and the hi-fi components that are cost a fortune. This is a return to high quality affordable kit philosophy behind Dynaco and Hafler. btw--I get nothing from this--I just think it's a worthy product and Dan is a good guy. -Kent check it out: http://www.akitika.com/.

I sold my Dynaco gear years ago in a quest for something "better." But as described in this thread, http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=8166 , I recently bought an ST-120 to restore and play with. As it turned out, I replaced virtually everything except the transformer so it's no longer a Dynaco. And although its 60wpc seems fine for driving my AR-3a's I'd rather have more oomph. I was using a MAC-4100 (100 wpc) for the past few years but recently switched to an Adcom GFA-555 II, which will deliver 325 watts into 4 ohms. BUT, I'd love a nice Dynaco 400 (especially one with the cool-looking meters!) Kent

Interesting. I decided to replace the two A15 appliance bulbs (upper left and right corners in the second and third photo above in Post #1) with LED bulbs to eliminate some of the heat. When I did, those bulbs remained lit--no flashing. Apparently whatever makes them flash is dependent on a temperature increase. I reinstalled the incandescent bulb on the right (first one in the circuit) and now the flashing works again, even with an LED in the other socket. That's good because the fibers tend to brush against that bulb and the LED is totally cold, so no chance of melting or scorching. -Kent

OK. My first attempt at posting on YouYube. We'll see how it turns out.....

Found this cool KLH sign on ebay for what seemed like a good price compared to the one or 2 others I've seen. Of course when it arrived I found "issues." These must have been dealers' signs back in the '60s or '70s. The sign lights up: The turquoise bars in the background flash on and off, and the "KLH" letters flash on/off and also sparkle! On this one the background did not light at all and the KLH letters only came on--no sparkle Opened it up. The background lights were no problem--they're just refrigerator type incandescent bulbs. I may replace them with A15 LED bulbs to cut down on the heat. The "sparkle" effect is produced by an odd looking bulb (obsolete projector lamp as it turns out) and a slowly-turning wheel. The light is transmitted to the KLH letters by fiber optics. Two big issues: The motor did not work, and what if the projector lamp blows? The back says new bulbs are available from Fibre-Lite Displays, Inc. but they're long gone. The bulb is marked "Sylvania DJS 6v 30w" and after extensive searching I found one.....for 50 bucks! But further searching turned up a substitute: DKN 35w 6v. And an ebay seller had them for $10. I don't think the additional 5w will be a problem. The motor is marked "Singer" (of course. So maybe this is from the '70s) "Model 414-173-20 115v 60Hz 3w 4RPM CCW". I was SURE I wouldn't find one of those! But.... Good ol' ebay to the rescue again! I found a Chinese seller who sells motors that "looked" a lot like the original. Metric of course but for $8.50 shipped I took a chance. This one is 4w and 5/6 RPM but close enough. And instead of a threaded shaft to hold the plastic wheel it had an internally-threaded shaft. This required some modification, but very little: Cut the aluminum bushing on the wheelUse a metric machine screw to affix the wheel to the motorBecause of the length of the motor's shaft I had to mount the motor on some spacers from my junk drawer.Not bad. The new motor was otherwise a perfect fit, right down to the spacing of the mounting holes! So that's it. First photo shows the Chinese & Singer motors. Second is the innerds "before" Third the innerds "after" and finally the sign lit up. Wish I could post a video here because it looks really cool! -Kent

Find the landfill that dumpster went to! I did not know Scott tubes amps had a center channel output but that sounds perfect to me. Don't know nothin' 'bout no bluetooth but maybe Pro could expound a bit. Any interest in making a mono system for somewhere? Have fun with this. -Kent

Many of us "of a certain age" had our first real hi-fi experience as a result of building dynakits. They were well-designed and, in kit form, cheap enough for a student or newly-wed to afford. The instruction booklets were well-written and illustrated. Darn near fool-proof. My first project was a Dynaco ST-35 tube amp that cost $45 including the tubes! A few years later I stepped up to the ST-120 and although some would argue the ST-35 was a "sweeter" little amp the 120 was pretty ground-breaking in its day. I eventually sold both (along with a PAT-4) but a couple of years ago I decided to get a used ST-120 to restore. CSP member John O'Hanlon helped me find some replacements for the big capacitors but the amp had other issues so I put it aside until a couple of weeks ago. I was looking for mods and upgrades (the 40+ year old design does have shortcomings) when I stumbled across a gold mine! http://www.updatemydynaco.com/ is a great site that offers a load of upgrades and improvements for the ST-120. Long story short: I ordered every possible upgrade (the "Full Monty"), leaving only the original chassis, power cord, binding posts and transformer. I opted to spend an extra $10 for the amp modules used the AkitikA GT-101 power amplifier. The difference between those and the regular ST-120 replacements: 0.1% versus 1% gain setting resistors, 10,000 uF output capacitors versus 3300 uF output capacitors. I also bought the new heat sinks (very nice but unnecessary), power supply upgrade, power supply and C12 caps and a blue LED mod for the power switch (purely cosmetic). The prices were very reasonable IMHO (total was under $200). I installed new RCA jacks and new feet that I had on hand but those are also available on the site. Delivery was FAST. All of the parts are high quality and the new printed circuit boards are well-made and clearly labeled. Instructions (available on the site) are as clear and complete as the original Dynaco manual. Best of all: The owner/designer Dan Joffe provides super-fast helpful tech support (I had made one bone-headed goof). So today I finished the amp and after bringing it up on a Variac (just a precaution) I gave it the real test: Powering the AR-3a's. The 3a's are supposedly power-hungry and at 4 ohms they pose a tricky load. I played a variety of music: Jazz, Rock, Classical (including organ) at decible levels WAY higher than normal. They sounded great. And the amp wasn't stressed at all. The heat sinks got barely tepid and there was no hint of clipping. According to Dan, the updated modules put out more than 50 Watts, but a shade less than 60 Watts into 8 Ohms and nearly 90 Watts into 4 Ohms. I plan to take the amp to my favorite tech for testing but to my ears it's all good. A few photos below of before & after, and the amp being auditioned. IMHO the updatemydynaco kits are true heirs to the Dynaco legacy and Dan Joffe may be the latter day David Hafler. And the tech support is incredible. If you have a tired old ST-120 do yourself a favor and update it with one or more of these modules. Don't have an ST-120? The AkitikA GT-101 provides the chassis and a modern torroidal transformer. Updatemydynaco also sells some modules and upgrades for the PAT-4 preamp, SCA-80 integrated amp and the mighty ST-400. Makes me sorry I sold my old PAT-4! I have no connection with this outfit--just a really satisfied customer. -Kent

How's the Dayton project coming along? Looks like the surround protrudes quite far. Does it hit the stock grille? What about xo? Does the PZ-2.1 xo design work? I have a pair of Mini 7s with one bad woofer. Had bought a pair of the MCM 55-1856 as replacements but it's a very tight fit. Kent

No. Virtually all speaker crossovers use standard sand cast resistors like those Erse ones. Here is a discussion: http://www.diyaudio.com/forums/multi-way/128821-non-inductive-resistors.html

alkermes, Thanks for the kind words. Now I have a question (I'm not an electronics expert by any means): Why do you advise against the metal oxide? I know that metal film may be more precise (+/- 1%) than metal oxide (+/- 5%) but is that critical? My recommendation for flame-proof comes from working on tube radios so I guess that's not a major consideration for solid state? Please 'splain. Carl, Good point regarding that metal plate. I'll reiterate my point that there is little reason to replace the binding posts--they work just fine. Leaving them preserves the vintage appearance (and value). If you want the convenience of dual banana plugs, Xmas's "dongle" is perfect. -Kent

They are fine. No need to get the Mills (guess you blew your budget on those Clarity Caps ). It's just their small size that makes them convenient. Here is a link to a Model Five Crossover I did with Erse caps. It's the later style crossover on a printed circuit board. Also used some Madisound surplus caps and Carlis http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7890 Replacing all the resistors with Erse cost $3.50. Using Mills would have cost $42.50. You can see the PCB is kind of crowded, especially with the physically larger Erse resistors, but it certainly can be done. On the hard-wired xo you have a bit more flexibility. A real cheapskate (like me) could use even more surplus caps: the 25uF could be 2 surplus 10uF + a Carli 4.7the 16uF could be 1 surplus 10uF + 2 surplus 2.7uFthe 4uF caps could be 2 surplus 2uFthe 3uF could be a surplus 2.7uF-Kent

Interesting post! Guess that settles once and for all what the cap values are. Wish I'd known this when I still had the Minis! I assume you plan to replace the unreliable PVC 90uF, now that you know the correct value. Not that you asked but if I were doing it I'd use either a 90uF electrolytic or maybe mix a 50uF 'lytic and four of the Madisound Surplus caps. The Mullard caps OTOH are considered to be desirable and should be retained. There's nothing mysterious about the color coding. I have a handy little cardboard pocket color code guide from Rat Shack that has capacitors on one side and resistors on the other. Here's what Wikipedia says about the color codes: The electronic color code is used to indicate the values or ratings of electronic components, very commonly for resistors, but also for capacitors, inductors, and others. A separate code, the 25-pair color code, is used to identify wires in sometelecommunications cables. The electronic color code was developed in the early 1920s by the Radio Manufacturers Association (now part of Electronic Industries Alliance[1] (EIA)), and was published as EIA-RS-279. The current international standard is IEC 60062.[2] Colorbands were commonly used (especially on resistors) because they were easily printed on tiny components, decreasing construction costs. However, there were drawbacks, especially for color blind people. Overheating of a component, or dirt accumulation, may make it impossible to distinguish brown from red from orange. Advances in printing technology have made printed numbers practical for small components, which are often found in modern electronics. I'd suggest testing the cabinets for air leakage by pushing in on the woofers, then decide if you want to use Roy's goo. If all the surrounds are cloth it probably couldn't hurt, but it may not be needed. Nice find! -Kent edit: I was baffled by your caps at first. They look like Red, Green, White, Red. Should have 5 bands so they must be Red Red Green White Red, in which case they would be 2,200,000pF 10% 250V, or 2.2 uF.

Hey Geoff I agree re the Advents. I spent a lot of time and too much money restoring some OLAs and they did not sound as good as AR2ax's. THE #1 classic KLH speaker is the Model Nine but that's an oddball. Electrostatic and really an Arthur Janszen speaker. The TOTL aside from that was the Model Twelve. Truly great speakers often available dirt cheap because they are big and heavy with a low WAF. Probably my fave is the Model Five. These were meant to compete head to head with the AR3a and they succeeded well. Basically the same drivers as the Twelves but in a cabinet about the size of the 3a. I have never seen the Model Twenty Eight but they are very cool looking, sort of like AR-LSTs. The Seventeen has a following but it's a step down from the Five. The Twenty is identical to the Seventeen but it's 4 ohms. Twenties are usually cheap. The Twenty Plus is a compact stereo system identical to the Twenty but with nicer cabinets and cool mid-century tulip stands. These sell for more than they're worth. The Twenty-Three is a fave of KLH guru Andrew Hayden. I have not heard them. KLH recycled the same basic 2-way design for a few of its speakers, both stand-alone and as part of a system. So there are some others in the Twenty-xx series that are similar. All of these speakers had cloth-surround woofers that benefit greatly from RoyC's butyl doping compound. That era KLH speakers have 2 Achilles' heels: Most used black and red PVC caps that are notorious for leakage. And the 5w resistors in the bigger speakers are too small--they should be replaced with 10w resistors when you recap the crossovers. Hope this is helpful. Kent

Nice find! You can download the service manual here: http://www.hifiengine.com/library/pioneer/sx-828.shtml Personally, I would not replace all the resistors. All the caps, yes but resistors don't normally go bad.* I did use Mills crossover resistors in Jim's Fives but in your receiver you want to use low tolerance flameproof metal oxide resistors and I would go up a step in wattage (replace 1/4 watt resistors with 1/2 watt, replace 1/2 watt with 1 watt). Here is an excellent overview of resistors: http://www.justradios.com/resistors.html and these people are good to deal with. On the off chance that they don't have what you need, Mouser is a good source. Finding 6 ohms could be tricky. Here is a 1/2 watt 5.9 ohm 1% http://www.mouser.com/ProductDetail/KOA-Speer/MOSX1-2CT52R5R90F/?qs=EI3zrt7d7sP0ZliK5XUlaQ%3d%3d Here's a 6.2 ohm 1w 5% from PE http://www.parts-express.com/62k-ohm-1w-flameproof-resistor-10-pcs--003-6.2k Kent *PS. But I WOULD replace all the resistors in your Model Fives. KLH used 5w sand cast resistors in those and I have seen more than one burned, blackened or cracked resistor in a KLH Five or Twelve. Use 10w resistors for peace of mind.** **PPS 8 years later(!!) Roy and I have discussed this on and off for a while. I think he found the best answer: Do replace the 5 ohm resistor with a 20 (yes 20) watt resistor. You can also replace the 15 ohm resistor in the Mid circuit with a 10 watt. The other 5 watt resistors should be fine.

Dig those super-tweeter cabinets!

Ah! Here it is. Post #25 by XMas111: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7994&page=2

Hi baski I re-capped some Fives (wonderful speakers) with Clarity Caps for one of our members, Redstone7: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=2557#entry74180 Regarding the binding posts: I agree with Roy but if you want to use banana plugs you could make little "dongles." One of our members posted a nice photo of some he made. Unfortunately I can't find them but the pic below should give you the general idea. Basically you take a short length of speaker wire and crimp a sta-kon ring terminal on one end and a female banana jack on the other. Put the ring terminal on the Five's stud and tighten it down well. Kent