RETROVOLTAGE

1946 Zenith 6-D-029 Consoltone Antique Radio Repair

Posted on April 7, 2014 by retrovoltage

This was a very interesting Zenith tabletop radio from just after WW2, the 1946 Zenith 6-D-029 Consoltone mantle radio. This is one of the iconic “boomerang” dials Zenith produced for a couple of years after the war. A variety of sets were made with similar styling; in this case the 6-D-029 is a 6-tube AC/DC radio with a combination of octals and loctal tubes.

This radio was repaired in the ’90s by a radio shop in Portland, OR but came to me in non-working condition. That’s not unreasonable for a radio to need another round of service after 20 years, and it looks like they did good work last time.

Checking out the tubes, other than one which was conveniently labeled (and testing confirmed) “weak”, they all had good filaments and good emissions. Something else was clearly the problem. Given the set’s owners don’t own a tube tester, the tube labeled “weak” must have been from the last time the radio was serviced; this one was the RF amplifier front-end tube.

It’s been pretty well cared for – the cabinet is in solid shape and there’s only a tiny amount of dust inside. Underneath, however…

There are several things going on here. Number one is somewhat obvious: something has released some smoke inside. In addition to that, the electrolytics used in this repair were different ages. There’s the blue CDE dual-section capacitor, and a Jamicon 33uF 450V capacitor hooked up as the second filter. Time to start pulling parts.

That Jamicon capacitor is visibly bulging from one side, and testing confirms it’s definitely dead. Of the CDE dual cap, one section was badly out of spec, and the other section tested open as well.

One of the ceramic disc capacitors blew itself apart – rather violently damaging a mylar capacitor near-by and generally making a mess of things. I replaced all of the same model of capacitor with new 630V film capacitors just to be safe.

After replacing the components it was time for the first power-up. No smoke! But, no sound either. Checking around on the voltages, something wasn’t quite right. B+ on the output tube was about 50% high, and there was no voltage on the screens of any tube.

Careful inspection and wire tracing got to the root of the problem: the wire between two tie points, supplying high voltage to the screens of the output tubes and the plate and screens of the RF and IF tubes, had broken at some point – likely from 68 years of metal fatigue. This was likely the root cause of the original failure: the ceramic disc capacitors were rated at 100V. With 4/6 tubes not conducting, the power supply was delivering over 160V when the nominal operating B+ was about 100V under load. This is well over the rating of those ceramic capacitors and could have caused the violent failure which took the radio out of service.

That’s more like it! A jumper confirms the issues has been located. The new capacitors are rated 630V, so should have no trouble with voltage spikes.

I soldered a 2″ segment of wire to make the connection permanently.

With that repair made, the radio fired up loud and clear!

Time to adjust the alignment a bit:

Then finally, back into the cabinet and ready to go home.

With all new film and electrolytic capacitors, and a replacement tube, this Zenith table radio is going to last a very long time before it needs to be serviced again and sound great the whole time.

Posted in Projects, Radios and Tubes, Vintage | Tagged 6-D-029, 6D029, antique radio, capacitor, capacitor replacement, Consoltone, old radio, radio, repair, restoration, tube radio, vacuum tube, vintage, vintage radio, zenith | 3 Comments

The Speaker Spotter – Speakers of Craigslist – April 4th, 2014

Posted on April 4, 2014 by retrovoltage

There’s always something interesting for sale on Craigslist, especially in Seattle. Do click the titles to see the original postings with more photos and additional information if you’re interested – otherwise, enjoy the virtual window shopping!

Today we’re featuring some speakers which are rare and nothing short of exotic – very interesting stuff!

Greybeard Audio KB22 Speakers – $800 in Renton

Audiophile Greybeard Audio KB22 Speakers 2

Audiophile Greybeard Audio KB22 Speakers 3

Weighing in at an astonishing 115 lbs. each and with an interesting tiled case, these Greybeard Audio speakers feature a 7″ woofer and 1″ dome tweeter and handle up to 300W at 6 ohms. At that weight, these must really have next to no resonance. I’d love to hear how these sound! I know these actually sold just a little while ago, but they’re so unique they deserved including anyway.

Duntech Soverign 2001s – $6500 in Poulsbo

These astonishingly massive speakers are reportedly regarded as some of the most accurate loudspeakers in the world, with 7 drivers in a time-aligned arrangement stacked vertically and weighing in at 325 lbs. each. With such a commanding presence, these make a serious statement.

Empire Royal Grenadiers Speakers with Marble Tops – $800 in Edmonds

Empire Royal Grenadiers Speakers with marble tops 2

These are a rare collector’s item from the 1960s and feature large cylindrical cabinets with marble tabletops. In addition to the visible drivers, there’s a 15″ downward-firing woofer in the bottom. The only trouble is, if these speakers sit without being used for many years, the woofer cone can sag out of alignment with the magnetic field and and cause poor performance. Reportedly, it can be fixed by reversing the polarity on the woofer, turning it upside down, and playing it for a while to shake the cone back into alignment although there are mixed reports of success with this approach. As long as the speakers are continually used they won’t suffer this issue but sitting for many years can cause the sag. The seller reports they don’t have a way to test them; as a part of an estate sale, I’d expect the woofer is probably suffering from sag and will need to be adjusted or replaced.

Pair of Modular Component Systems MCS 8320 Linear Phase Speakers – $65 on Vashon Island

MCS was the JC Penny house brand, but in the ’70s even house brand speakers could be pretty decent. These 3-way MCS speakers feature time-corrected driver alignment.

Pair of Wharfedale PPX-1 Speakers – $60 in Northgate

These are a bit of a mystery. The seller doesn’t have much info other than they take 70W at 8 Ohms, and are 22″ x 20″ flat speakers. Are these electrostatic panels? Or a proprietary short depth speaker? Difficult to tell the date, too.

Petroff Labs Reference 3-way Speakers – $550 in Bremerton

Featuring 12″ woofers, 6″ midrange and a 2″ ribbon tweeter, I’m sure these interesting trapezoidal oak speakers sound as good as they look!

Polk RTIA9 Tower Speakers – $1100 in Issaquah

These beastly tower speakers by Polk Audio have an interesting driver compliment – three 7″ woofers, two 5.25″ midrange drivers in their own tuned internal enclosure and a 1″ dome tweeter, these speakers are flat from 30-26,000 Hz and accept up to 500W of input power. These would be great front channels for a powerful home theatre system!

Vintage JBL C35 James B. Lansing Speakers – $1800 in Burien

These JBLs look to be from the late ’60s, possibly early ’70s, and seem to have a large single full-range driver installed in the cabinet. JBL’s vintage speakers are all known to be pretty fantastic and I assume these are no different.

Vintage Kenwood KL-8080X Speakers – $500 in Bremerton

These mammoth late ’70s, possibly early ’80s Kenwood speakers, feature a 5-way design in a ported enclosure with a 15″ woofer, 6″ mid, tweeter, super-tweeter, and horn with level adjustments. I’m very curious how these sound – Kenwood’s vintage products tended to be pretty well designed but I’m not familiar with these ones specifically. I do think the price is a bit high, but these have been up on Craigslist for months, the seller might be a little flexible now.

Like what you see? Check out more back issues of the Speaker Spotter.

Posted in Audio, Collections, Hi-Fi, Photos, Speakers, Stereo | Tagged 2001, 8320, audiophile, C35, dome, Duntech, Duntech Soverign, Empire, Empire Royal Grenadiers, Famous Johnzer, Grenadiers, Greybeard, Greybeard Audio KB22, hi-fi, Horn, James B Lansing, jbl, JBL C35, Johnzer, KB22, kenwood, Kenwood KL-8080X, KL-8080X, marble, MCS, MCS 8320, mid, Modular Component Systems, Petroff, Petroff Labs, Petroff Labs Reference, Polk, Polk Audio, Polk Audio RTIA9, Polk RTIA9, PPX-1, Reference, Royal, RTIA9, Soverign, Speakers, tile, tweeter, vintage, Wharfedale, Wharfedale PPX-1, woofer | Leave a comment

1940 Philco 40-185XF Antique Radio Restoration

Posted on April 2, 2014 by retrovoltage

I had the privilege of working on a very well preserved Philco 40-185XF recently. These are top performing pre-war sets featuring 8 tubes, an RF amplifier front-end and push-pull audio output into a 12″ speaker. Definitely worth fixing up! This radio had been its owner’s family for years – first in his grandparent’s home, then with his parents, before it passed on to him. After serving as a conversation piece for many years, it was time to get it going again.

This model had been sitting silently since the 1970s and was ready to come back to life. It came to me for a complete overhaul, including testing all the tubes to replace as needed, re-stringing the dial, replacing hardened rubber mounts and eroded pushbuttons, and a precision alignment.

The underside is nicely laid out and pretty easy to work on. There’s a few capacitors which are buried, but most are easily accessible. The output transformer, top left, is mounted under the chassis instead of on the speaker as was more common on earlier sets.

Component replacement was initially pretty straightforward. The preset assembly was held in by two screws and had plenty of slack to fold it up and out of the way to allow easy access to the components beneath it. There were several small capacitors and an electrolytic can mounted under the pushbutton assembly.

The power cord was in dire need of replacement, so it received a new polarized plug and new X1Y2-rated safety capacitors on a newly mounted terminal strip.

With component replacement complete, it was time for a first power-up and a test signal. All seemed to be good at first for a bit…but then the radio sputtered a bit and cut out entirely – then some faint smoke started to appear! Bad, bad sign. I killed the power quickly to avoid damaging anything and carefully inspected the fault.

On this schematic snip, the resistor circled in red was the one which was overheating and smoking. This resistor feeds the high voltage to the front-end of the radio; overheating means excess current drawn. I pulled those tubes, but it continued to smoke, so further investigation was necessary. First, I replaced that resistor with a new one which hadn’t been heat-damaged.

It’s a bit faint, but the insulation had cracked off the wires leading into the IF can and were shorting to the chassis. That’d be the problem! Time to pull the IF can:

Some wires were cloth and some rubber-coated; some of the rubber coated ones were fine, and some were brittle and cracking. I sleeved the damaged wires, then reinstalled the transformer in the can and mounted it back up. One problem solved! The short circuit was fixed, but there was still no audio output – even when injecting directly into the audio amplifier circuit.

There were some clicks when I’d touch certain resistors with a probe. The resistors had overwhelmingly tested within tolerance so most were left original, but something happened along the way. I pulled the suspect resistors to replace, and examined the old one:

It’s tough to see – but the body of the resistor is cracked! This was a new problem. What happened is: carbon composition resistors absorb moisture from the atmosphere over time. In this case, the radio is 74 years old, and 44 of those years it sat without being played. Resistors also dissipate heat when they’re operating. This combination caused the absorbed moisture to expand and escape by cracking the body of the resistor and causing intermittent opens. Not good for performance! I replaced nearly all the remaining resistors at this point.

The replacements are 1% tolerance precision metal film resistors which should last for a very long time, and don’t absorb moisture the way carbon resistors do. Now, I was able to get audio, but no radio reception. Testing the front-end verified the radio was operating, but it wasn’t tuning a signal. Time to investigate the band switch – which, surprise, was badly gunked up! The mechanism wasn’t allowing the tuning capacitor to engage, and all the contacts were badly corroded which was killing the signal.

You can see how much gunk and oxidation had caked up onto the switch contacts – on the left, not processed; on the right, cleaned and scrubbed.

With that, the radio roared to life and picked up stations loud and clear across the dial! There were a lot of problems, but they were all able to be corrected. I peaked up the alignment using my standard signal generator, then did final inspection checks.

Finally, it was ready for the trip home! It sounded even better installed back in the cabinet.

The owners had the cabinet refinished while the radio was in the shop – it’s a perfect pairing! New pushbuttons and new rubber mounts and the radio is nearly as nice as they day it left the showroom floor.

This family heirloom is back in running shape and is going to serve faithfully for many years to come as a beautiful piece of functional furniture. Just look at it!

Posted in Projects, Radios and Tubes, Vintage | Tagged 40-185, 40-185XF, antique radio, capacitor, capacitor replacement, philco, radio, repair, restoration, tube radio, vacuum tube, vintage, vintage radio | 3 Comments

1938 Zenith 5-S-220 eBay Tune-Up Special

Posted on March 26, 2014 by retrovoltage

I’ve had the opportunity to work on several very nice Zenith radios lately and this one is especially interesting. It’s the Zenith 5-S-220 Cube. This is the first time I’ve seen one of these in person, they’re somewhat uncommon. Electrically, it’s a nice 5-tube radio with a broadcast and shortwave band, and the cabinet is very compact with the speaker firing vertically through the top of the cabinet. The black dial in the face is very easy to fine-tune.

It was sold as in running condition, and it worked okay on the standard broadcast setting, but with the switch on the Treble Cut tone setting the set picked up bad warbling low-frequency interference, called motor-boating. It also just didn’t sound that good, and Zenith radios are known for their excellent tone even from their small radios.

The chassis is supported on small risers to replace compressed paper spacers. It’s fairly cramped in there,but the chassis slides out easily when the spacers are pulled out and the speaker socket makes service easy.

Underneath, the solder joints were all very good in fact. Mostly original resistors retained.I tested the resistors and many were well outside of their specifications; there were several other problems as well.

The previous service had replaced all but one of the original vintage tubular capacitors that are candidates for replacement in any vintage radio.

The resistors were all original. This frequently isn’t a problem – vintage resistors can still test within tolerance, and if so, don’t need to be replaced – but these were almost all bad. I found some which measured as much as 250% of their marked values. The radio actually played like this, it just goes to show you how robust these tube circuits were. They’d tolerate a lot of abuse and still sound passable.

I replaced the vintage capacitor and many resistors but the motor-boating persisted. Throughout all of this, the volume is lower than I’d expect, too. I went about replacing the Micamold capacitors which can frequently go leaky and exhibit odd symptoms. These are in fact paper capacitors in a molded package – not true mica capacitors which tend to hold up well even today.

While poking around at those connections, an entire solder blob moved – the ground connection had broken off entirely:

I replaced this one with a true mica capacitor and a solid ground connection. A few tweaks to the alignment later, the motor boating was gone, but the low volume persisted. Even on the normal position it was still lower than it should have been. I examined the tube line-up versus the schematic. This radio had a 6V6GT tube installed when the radio was designed for a 6F6G tube.

In general, those tubes are “fairly” close and you can often plug them into each other’s sockets. The radio will play, but with more distortion and lower volume, as they do have distinct design characteristics. The mismatch will get you significantly lower volume as a result, too. I had a 6F6G which tested like new in stock and made the exchange:

With this, the radio roared to life with perfect volume. It sounds absolutely fantastic, especially for such a small cabinet and speaker. It also goes to show: be cautious buying radios on eBay. They might even work, but often may have hidden problems like this. It’s worth it to ask for under-chassis photos to check the amount of work that was done.

With the feedback problem corrected, I performed a precision alignment and the dial tracks in perfectly.

Overall, to bring this radio up to standard I replaced many resistors, replaced several capacitors with modern technologies, repaired a broken ground connection for the capacitors, aligned the radio using a standard signal generator, and replaced a wrong tube. Now it looks as good as it sounds – practically brand new.

Posted in Electronics, Projects, Radios and Tubes, Vintage | Tagged 5-s-220, 5s220, antique radio, antique radio repair seattle, buyer beware, capacitor, capacitor replacement, Craigslist, cube, eBay, repair, restoration, shortwave, tube radio, vacuum tube, vintage, vintage radio, vintage radio repair seattle, zenith, zenith 5-s-220, zenith 5s220 | Leave a comment

The Speaker Spotter – Speakers of Craigslist – March 21st, 2014

Posted on March 21, 2014 by retrovoltage

There’s always something interesting for sale on Craigslist, especially in Seattle. Here’s a selection of especially notable vintage speakers and other audio products for sale on the local Craigslist. I’m not affiliated with any of these sales, but if you’re interested, you should contact the seller through the respective Craigslist page! Do click through each of the titles – the original postings contain a lot more information and many more photos, along with the seller’s contact information to request more information. If the ads are removed, the speaker probably sold, so don’t be alarmed if some links don’t work. Try searching for the keywords as sometimes they expire or are reposted.

Today we have several unusual boutique hi-fi speakers, plenty of vintage JBLs, and an interesting set of Klipsch La Scalas designed for stage use.

Cerwin Vega Speakers – $125 in Olympia

Cerwin Vega speakers are known as great rock speakers that can handle a ton of power and pump out a lot of bass. I’ve owned a pair and they are great performing, general use speakers. The iconic red foam surround and solid wood grain are very attractive and eye-catching, too.

DCM TimeWindow 1A Speakers – $200 in Ballard

I understand DCM Time speakers to be nice and accurate, if a bit understated, but I’ve not heard them myself. Based on the cabinet design I expect these might be bipolar speakers? Looks worth investigating!

JBL 4330 Custom Studio Monitors – $3000 in Eguene, OR

If you’re into music production, or just like an extremely accurate listening experience, these might be for you. They feature the iconic biradial “butt cheeks” horn and what looks like it could be a 15″ woofer. I’m sure this is both powerful and great sounding.

JBL LE-8 Vintage Speakers – $299 in the Renton Highlands

A throwback from the modern reference quality JBL above, these are very vintage JBL bookshelf speakers with a single full-range driver installed. I’m sure they’d sound very warm with a matching vintage tube amp or low powered transistor amp up to a couple dozen watts, but might not have the same clarity and definition you’d get with a slightly newer, multi-driver speaker system.

Klipsch La Scala LSI – $1500 in North Bend

The Klipsch La Scala is another of their high-end folded horn speakers; these are the LSI variant which are designed to be stage speakers with detachable treble horn cabinets. The seller claims these were never hauled around to gigs, though, and are in great shape. The same great sound from a Klipsch folded horn, but in a bit more industrial of a package.

Revox AX5-4 Speakers – $295 on Seattle’s Eastside

From 1977, I’m not familiar with this brand, but they’re reportedly using high-end German manufactured drivers; a 3-way design with dual woofers can probably offer plenty of bass. The mid driver resembles the Infinity polymer dome, too. Rated for 100 W power handling at 4 Ohms, 91 dB efficiency these seem like they’d be worth checking out. I’d love to listen.

Snell C IV Speakers – $399 in the Renton Highlands

These Canadian hi-fi speakers have some interesting engineering in them, including a zero diffraction grill which is designed to be more sonicly transparent, and an interesting dual tweeter design with a front-firing tweeter on a fourth-order crossover, and a rear-firing dome tweeter on a first-order crossover. This combination apparently delivers great accuracy from the front while the rear – which can be disabled – fills out the volume lost due to the steep crossover slope.

Totem ARRO Speakers – $800 in Auburn

These no-frills 2-way audiophile speakers look like as much of a decor statement as a music piece. They’re “wife friendly” and yet regarded for excellent bass response and well defined imaging. I’m not sure it would match every decor but it’s very pretty.

Universal CX-300 Hi-Fi Speakers – $140 in Everett

These early ’60s drivers throw back to the coaxial design which was more common at the time. With 25W of power handling and meeting the DIN Hi-Fi spec of 40-18,000 Hz frequency response I bet these sound great with a period tube amp like they would’ve used originally.

Vintage JBL L88 Nova Loudspeakers – $400 in Tacoma

These are beautiful speakers which look to be from about the early ’70s. I’m sure they sound fantastic like most JBLs, especially vintage JBLs, and would make a perfect vintage hi-fi bookshelf or desktop system that would look great in almost any room.

More Speaker Spotter

Posted in Audio, Collections, Photos, Speakers, Stereo, Vintage | Tagged 1A, 4330, AX5-4, bi-radial, biradial, butt cheeks, Cerwin, Cerwin Vega, CX-300, DCM, hi-fi, Horn, jbl, JBL 4330, JBL L88, JBL LE-8, Klipsch, L88, La Scala, Lascala, LE-8, loudspeaker, LSI, Monitor, monitors, Revox, Revox AX5-4, Snell, Snell C, speaker, speaker spotter, Speakers, studio monitors, Time, TimeWindow, Totem, Totem ARRO, Universal, Universal CX-300, Vega, vintage | 1 Comment

Craigslist and eBay Antique Radios – Be Careful!

Posted on March 19, 2014 by retrovoltage

It’s not uncommon to run across antique or vintage radios on Craigslist, eBay and other sales site which are advertised as “working”, “repaired” or “restored”. Many times these are in fact professionally reconditioned items – just like you read about here – but occasionally, there are some critical hidden problems to look out for. Let’s take a look at an underside photo which was included in the for sale posting:

Not too bad! It looks like there’s some new capacitors carefully installed – but there’s a problem. Can you spot it?

Again, with a hint this time! Several original paper capacitors look to be installed in the radio. It’s even believable they might work – by and large they’ll be well past their service lifetime, but through dumb luck you do occasionally find vintage capacitors which are still technically operational. Even if one is working now, though, they are universally all completely unsafe for operation for any length of time. Old vintage capacitors like these can spontaneously fail and short out, which can damage the radio or even start a fire! A repair like this is not in compliance with the best practices for antique radio repair, and I wouldn’t let one out of my shop in such a condition, that’s for sure!

If you’re buying an antique radio or vintage radio and have the opportunity, ask for photos of the underside of the chassis or ask to inspect it personally and check for old parts. If you’re having your old radio serviced, make sure to choose a reputable repair shop or service technician who will follow best practices and replace all components which are subject to spontaneous failure – not just the ones which are bad “right now”. Your radio – and maybe your home – depend on it!

Posted in Commentary, Electronics, Photos, Radios and Tubes, Vintage | Tagged antique radio, capacitor, capacitor replacement, fried electronics, radio, repair, restoration, tube radio, vacuum tube, vintage, vintage radio | 4 Comments

The Speaker Spotter – Speakers of Craigslist – March 14th, 2014

Posted on March 14, 2014 by retrovoltage

It’s a good week for rare and unusual speakers in Seattle this week – several Electro-Voice vintage speakers, and the Altec Lansing Voice of the Theater!

Bose Speakers and Amplifier – $300 in Port Orchard

This looks like a ready-to-go kit of Series IV or V speakers, Active Equalizer, and an unknown amplifier with two very large power meters. These also sound fantastic. Series III+ speakers used a design with resonant acoustic cavities as opposed to the acoustic suspension enclosure of the Series I/II and also sound fantastic. It’s worth double-checking the foam on Series III+ Bose drivers, though.

Bose 901 Speakers with Equalizer – $250 in Port Orchard

This is a great price for a set of Bose 901 Series I/II speakers with a working equalizer, and of course Bose 901s are a very musical and life-like speaker to buy. Series I/II have cloth rubber surrounds on the drivers, as well, so you don’t have to worry about refoaming 18 drivers.

Electro-Voice Regenecys – $400 in East Wenatchee

E-V speakers are pretty rare, they stopped making consumer gear in the ’70s. They made some of the finest speaker drivers and their finished speaker products are incredible as well. These feature 15″ woofers, T25 mid horns and T35 tweeter horns. Very similar driver compliment to a Klipsch Cornwall, for example. I bet these sound fantastic!

Electro-Voice Hi-Fi Speakers – $250 in Bellevue

I haven’t seen these before, but they look very interested. It looks like they have the SP12 extended response 12″ woofers, the T-25A midrange (same as on the Regency), but are missing what was likely a T-35 tweeter. You’d probably need to spend $100-200 on the missing drivers, but I bet these would sound very good complete.

Klipsch KG4 – $120 in SeaTac

Despite some water damage, these speakers are a bargain – featuring an exponential horn, two 8″ active woofers and a 12″ passive radiator on the rear. They sound great and are very efficient – my pair sound fantastic. The water damage on these looks like it’d be pretty easy to refinish, too.

Klipsch Speakers – $600 in Granite Falls

Always a good find, these black Heresy II speakers look like they’re in great shape. They’re one of my favorite little speakers.

Pair of Vintage Wharfedale Speakers – $100

These look like they’re from the 1960s, possible a little earlier. I’ve never heard any Wharfedale speakers, but being a high-end brand from the golden age of hi-fi, these are almost certainly worth listening to and the price seems pretty fair.

Sansui S-1117 Tower Speaker System – $100 in Tacoma

These get a listing because they’re “interesting”, although they don’t have a reputation for good sound. With a pair of 12″s in each cabinet, though, they probably can deliver a decent amount of bass and they sure look very visually impressive. It’s unfortunate one has a replaced woofer.

Speakerlab SKO Speakers – $750 in South Seattle

I think this is the late-generation Speakerlab Corner Horn after they moved away from the Klipschorn-inspired design. These have been mounted angled slightly back on speaker stands. I’m not sure what to make of the whole thing, personally, but given the 15″ woofer inside the folded horn and the T35 tweeter, I’m sure they can deliver.

Electro-Voice “The Duchess” Speakers (1962) – $900 in Lynnwood

Very rare speakers, but these are missing some parts, and I’m unclear from the description whether they are functional with the modification. Might make a good, if somewhat expensive, project to have a very desirable vintage speaker.

Vintage Akai SW 177 Speakers – $40

I’m sure these would make a great garage speaker – a 15″ woofer, mid, dual tweeters, and durable butyl rubber surrounds on the drivers.

Vintage Sansui SP-100 Stereo Speakers – $55 in Edmonds

I just love the look of Sansui vintage speakers with the scalloped wood grills and solid wood cabinets, often with heavy dampening inside. These are a very early series with a woofer, mid-range, and a horn tweeter. The crossover will certainly need to be rebuilt for best performance, but you’d have an inexpensive vintage hi-fi setup with warm and rich sound.

Vintage Wharfedale W-35 Speakers – $400 in West Bremerton

A bit smaller than the other Wharfedale speakers, and a bit more expensive, I’d love to know more about the features and differences of those two models.

Altec Lansing Voice of the Theater Speakers – $50,000 in Redmond

“A better investment than a Porsche” these holy grail speakers out of Redmond, home of an unlimited amount of tech money, aren’t for everyone but they might be right for you. Originally these were high-end PA Hi-Fi speakers for movie theaters, etc. they feature large an powerful woofers mounted in flared horn enclosures and enormous multi-cell horns coupled to compression drivers. They’re known as being incredibly efficient, absurdly powerful speakers and might actually be a better investment than that sportscar.

If you’re interested in any of these speakers, click on the title to visit the original Craigslist posting to contact the seller!

Do you know anything about those Wharfedales? Or own a pair of the speakers listed here? Leave a comment!

More Speaker Spotter

Posted in Audio, Collections, Photos, Speakers, Stereo, Vintage | Tagged 12W, 15W, Active Equalizer, Akai, altec, altec lansing, Bose, Bose 901, cornwall, Craigslist, Duchess, E-V, Electro-Voice, Electrovoice, Equalizer, EV, heresy, heresy II, KG4, Klipsch, Regency, S-1117, Sansui, series I, series II, series IV, Series V, SKO, SP-100, SP-12, SP12, speaker, speaker spotter, speakerlab, Speakers, speakers of craigslist, SW 177, T25, T25A, T35, The Duchess, Voice of the Theater, Voice of the Theatre, W-35, WD-35, Wharfedale | 2 Comments

1939 RCA K-60 Console Radio Repairs

Posted on March 10, 2014 by retrovoltage

This beautifully preserved RCA K-60 radio came to me after a Golden Retriever puppy got a little too up close and personal.

Otherwise, it’s been beautifully refinished in the past, and was fully overhauled in the late ’90s according to a stamp on the rear of the chassis and the replacement speaker.

Replacement grille cloth is somewhat hard to find these days, but the pattern was almost a perfect match. It’s much cleaner, too! The speaker must have failed at one point, because it had been replaced. I’d have picked a different substitute driver myself, but this one seemed to work well enough.

On the rear, the output transformer and speaker lead connections were relocated to the basket.

Unfortunately, during transport, the field coil (which had been retained but relocated) wasn’t securely mounted and ripped from its mounting point, damaging the speaker voice coil leads in the process.

I carefully peeled back the paper and soldered new, stronger leads; then reinforced the structure with Gorilla tape. The new coil checks out – about 1K Ohms resistance, and 2.3 Henry of inductance. That’s a lot! Any further back of a break would have been much more complicated to successfully fix.

Before this repair, the field coil was just hanging from a peg with exposed metal clips into the coil – a major shock hazard, with several hundred volts present on an externally exposed, uncovered piece of metal!

‘

And, all set!

After a short power-up to make sure the field coil repair was sound, she’s ready to go home! Hopefully the puppy has learned a few lessons about the proper handling of antiques in the past few weeks so we can avoid a repeat performance.

Posted in Projects, Radios and Tubes, Vintage | Tagged antique radio, grill cloth, grille cloth, K-60, rca, RCA K-60, tube radio, vintage radio | Leave a comment

The Speaker Spotter – Speakers of Craigslist – March 7th, 2014

Posted on March 7, 2014 by retrovoltage

This issue of the Speaker Spotter covers both interesting finds in Seattle and Portland since last week. And so:

Vintage Allison One Speakers

I bet these have a very wide sound stage from the bipolar angled design.

Bose 601 Series III Speakers – $700

Bose 601 Direct/Reflecting speakers produce a very wide, warm, rich sound that’s very life-like. The 601 speakers feature a pair of 8″ woofers and 4 tweeters arranged in a reflecting pattern. When properly set up in a room they sound excellent.

Used Speakerlab K-Horn DIYs – $250

These speakers started out as the flat-pack kit Speakerlab K-Horns, but the builder took some liberty with the designs. Instead of the same driver compliment usually found on the Klipschorns, with the pair of Electro-Voice mid and high horn drivers, they seem to have elected to build the bass cabinets and use alternate mid and high frequency drivers in separate enclosures. This would make the base of an interesting frankenhorn system, perhaps paired with an Altec or JBL multicell horn on top?

Vintage Fisher XP95B Speakers – $50

From before Fisher went a bit downmarket, these look pretty interesting and might perform well. The seller reports the woofers (12″ or 15″) have been refoamed, and the phenolic ring tweeters typically appeared on higher end equipment, including speakers made by Altec Lansing and Marantz.

Infinity Kappa 8 Speakers – $300

Vintage Infinity speakers aren’t especially common in my experience. These are shallow 4-way designs featuring a pair of Emit planar tweeters (one in front, one on the rear) with dome midrange drivers. The Emit tweeters are bright and crisp, I bet these have a lot of definition in the high end.

Vintage Infinity RSe – $140

With what looks to be 8″ woofers and horizontally mounted Emit planar tweeters, these vintage Infinity bookshelf speakers probably sound great for near-field listening.

Two Pair Vintage Kenwood Speakers – $180

I rather like the vintage wood lattice grille Kenwood speakers. In this case, this is a pair of KL-777As, 4-way/6-driver, and a pair of 333D 3-way/3-driver speakers. These are known for being very lively and musical and would make an excellent, affordable vintage quad system.

Marantz Speakers LS-20 – $300

I don’t run into Marantz speakers very often and haven’t heard a set myself, but I know they have a reputation for being able to thump and in general sounding excellent. These look like they’re from the ’80s, a bit flashy, but worth checking out!

Sonab OA-14 Speakers Made in Sweden – $850

These are pretty rare vintage hi-fi speakers from Sweden. They have an interesting reflecting design that reminds me a bit of the Bose 601, with angled upward-firing woofers and four tweeters. It’s a very interesting design, I’m curious how they sound!

Speakerlab Corner Horns – $1600

These have been on Craigslist a few times in the local area in the last year. It looks like they’ve changed hands since the last time, and the price is considerably higher. These have the 15″ woofer inside the folded horn and an Electro-Voice tweeter, but feature a 6.5″ midrange driver instead of a midrange horn. I believe this was the last year Speakerlab sold the corner horn design, which had moved away from the Klipsch-inspired design of the Speakerlab K.

Speakerlab Six

You don’t see these very often, the Speakerlab Six is one size down from the Super 7s. The main difference is the Six lacks the 10″ passive radiator found on the Seven, and accordingly different driver placement.

If one of these speakers looks interesting, click through to Craigslist and contact the seller!

Previous issues of the Speaker Spotter.

Posted in Audio, Collections, Photos, Speakers, Stereo, Vintage | Tagged Allison, Allison One, Bose, Bose 601, Corner Horn, Craigslist, Fisher, Fisher XP95B, Infinity, Infinity Kappa 8, Infinity RSe, k horn, Kappa 8, kenwood, KL-333D, KL-777A, klipschorn, LS-20, Marantz, Marantz LS-20, OA-14, photo, photos, RSe, series III, Seven, Six, Sonab, Sonab OA-14, speaker, speaker spotter, speakerlab, Speakers, speakers of craigslist, Super Seven, vintage, XP95B | 1 Comment

Ohm Acoustics Model D Speaker Refurbishment

Posted on February 21, 2014 by retrovoltage

Classic speakers are always a delight to work on, and speakers have capacitors and other parts which require service, too. Over the years those components can fail and result in poor sound and even potential speaker damage.

In this case, the speakers on the bench are the Ohm Acoustics Model D. Ohm is more well-known for the Walsh speakers which produce an interesting omnidirectional sound from a vertically oriented cone; these Model D speakers were a more economical version that still offers warm and rich sound, especially known as being great for rock and roll music.

Ohm is still in business making boutique hi-fi speakers, and these speakers which originally cost $400 a pair in the early 1970s are still worth a $400 trade-in credit towards a new set today. They feature a 10″ woofer and a phenolic ring tweeter packaged in a solid hardwood cabinet with a resistive port. A resistive port is half-way between an acoustic suspension enclosure and a reflex enclosure, it’s not the most common design. Inside, there’s a 2 uF and a 20 uF crossover capacitor, an inductor, and a rheostat to adjust the tweeter level.

These speakers were used for only a few years in the ’70s, picking up only the tiniest of nicks and dings, before they were put back in their original boxes and stored for the next 40 years. Even with such careful storage, though, the woofer foam had degraded and was due to be replaced – so the first order of business was new foam surrounds.

Then it was to address the crossovers.

Bad capacitors mean bad sound! And this one certainly was bad. It’s supposed to measure 20 uF, but instead is measuring 0.0013 uF. That’s no good at all.

And this one’s showing more ESR than I’d like:

Beautiful classic speakers like this deserve nothing but the best, so I used brand new audiophile grade film crossover capacitors which are exceptionally stable and have a low dissipation factor for unmatched performance.

It was rather interesting – these were purchased as a pair, but inside, used slightly different capacitors. Both of the same value, but one used a single 20 uF bipolar capacitor and the other used a pair of 10 uF in parallel.