Quick on-site testing
With thrift-store audio components, testing is not only possible but necessary. Anything marked “as-is” or “minimally tested” (that means they turned it ON) often can’t be returned, and a lot of stuff gets dropped off because it no longer works. Check the store’s policy. Some take returns if you leave the label on the unit, so check it out thoroughly before removing it.
But keep in mind that “no longer works” can be subjective, and may be a simple case of operator error. Many users today simply have no idea what happens when you hit a “tape monitor,” “FM mute,” or “speaker” selector on a receiver or that they even have fuses, so a lot of “defective” gear really isn’tâ€”you just have to check everything to make sure.
Here’s what you need on-site, which can easily fit in a coat pocket:
Pair of headphones (lightweight and cheap are fine) with a Â¼” adaptor to fit full-sized front-panel receiver/amplifier jacks
Assorted audio fuses, 2-5amp
Small straight-bladed screwdriver and small Phillips screwdriver
Audio sourceâ€”can be an iPod or other player, or a portable CD player.
Cable for connecting the above (sub-mini headphone to stereo RCA)
Discsâ€”only if you’re looking at CD players and changers
Speaker wire pre-strippedâ€”only if you want to live test an amplifier section
You do need to test potential audio rescues on-site, but you don’t need much to do itâ€”everything can fit in a coat pocket. Carry a pair of lightweight headphones or earbuds (don’t forget the Â¼- inch adaptor), a small screwdriver (for opening gear if necessary, prying off speaker grilles, and testing FM operation as a makeshift antenna), an audio source with RCA output cable, a few CD’s for players and changers, and a short pair of speaker wires for checking amplifier sections using speakers on-hand. The last item is really importantâ€”many receivers and integrateds with serious output problems may sound find just driving headphones. If you can’t check gear on-site with speakers make sure you know the store’s return policies.
First, locate the AC wall outlets in the thrift store. This is often easier said than done. It will usually be the place with a line of people waiting to check out everything from vacuum cleaners and power tools to fish-tank pumps and table lamps (see the previous note on weekends being a lousy time to do this). Note: this is where having a friend in the store is handy, since they can tell you where the other outlets are.
Once you have power you can quick-test a receiver or amplifier to see if it’s worth bringing home. First, turn the unit ON. If there is a protection indicator and it never goes away, you can move on. If not, go to the next step.
You can rule a receiver out with a very simple procedure. Turn the selector to FM, and take your small screwdriver and contact one of the FM ANTENNA leads on the back (older units may have separate 300 Ohm and 75 Ohm inputs, if it just has a coaxial 75 Ohm input contact the center connector). Your body is the antenna here, and you’re not looking for perfectionâ€”just signal. Select a few local stations. Check the FM MUTE button as well, without a proper antenna its threshold may stomp all over any stations so turn it off.
If the FM tuning indicators show STEREO and/or any signal strength, chances are the receiver is workingâ€”at least as a preamplifier. Plug in the headphones (watch the volume level) and check for any gross or noticeable distortion, but remember that if the muting is OFF you may be getting a lot of FM noise so check a strong station or use your iPod or MP3/CD player to make sure. You can use the same method to check out a tuner, even if it has no headphone jack.
One thing to watch out for using FM as a test source are high-end receivers and tuners with provision for Dolby FM. They may require an external adaptor, in which case you won’t hear anything if that function is selected. My prize $10 Sony STR-5800 (ES-series forerunner) initially threw me on that one with its stealthy EXT ADPT button.
If the unit is an integrated amplifier, plug your iPod or MP3/CD player into the CD or AUX inputs on the back and use the headphones in the same manner as with a receiver. Processors and equalizers are harder to test on-site, so make sure you can return them.
More advanced testing for receivers and amplifiers
On both receivers and integrated amplifiers, if you see a visual indicator of a signal but get no sound (especially with speakers connected) don’t be discouraged. It can mean the following. Some of these conditions apply to speakers and not headphones, so you’ll probably do more advanced testing at home. But if you carry a set of short, pre-stripped speaker wires and grab a handy pair of speakers in the thrift store you can try it right there.
Tape Monitor is ON. Turn it OFF. On older high-quality units such as Yamaha receivers and integrateds there are separate TAPE and SOURCE selectors which are easy to mess up, so check them carefully. Apply the same logic to anything that says “processor loop” or “external adaptor” on the front panel, which can also be an easily-overlooked no-sound culprit.
Blown fuses: Most older units have audio-output fuses either on the back panel in sockets or internally (not to be confused with the main power supply fuse). Check them carefully, if they look broken or vaporized you won’t hear anything. If you have replacement fuses try them; if not at least the preamplifier stage is working and it might be worth taking it home to replace the fuses. Note: a unit with blown internal fuses may sound fine on headphones.
Note on fuses: I once found a Sansui receiver that lit up perfectly and grabbed FM signals like it was an RF vacuum cleaner, but it sounded terrible with excessive distortion in one channel. But since I had it open and the fuses looked funky I replaced them, and prestoâ€”the thing sounded great. I have no idea why that worked, but ever since I’ve taken protection fuses very seriously with older gear.
Pre-Amp/Power Amp jumpers or switches: Many older units had a provision for separating the pre-amp and power amplifier stages, so a receiver could be used as a tuner-preamplifier with a much more powerful amplifier for example. Often there are separate input/output jacks on the rear panel for this, with either jumpers (which may be missing) or a switch (which may be in the wrong position). Check both. Note: a unit with a separated preamplifier stage may sound fine on headphones.
With an amplifier or receiver, always make sure you try it out with an actual load connected (a speaker). I picked up a handsome old Kenwood KR-6160 receiver that worked perfectly on headphones, until I connected speakers. The unit made an awful “motor boating” sound and smoke started pouring out of the output devices. I may still try and salvage it as a preamp-tuner, but the lesson is don’t assume that just because an old receiver or amplifier sounds fine with headphones it’s working properly.
CD players and changers
CD players and changes are easy to check. Just load in a disc and check operation. Many have headphone jacks so you can easily monitor the results. You can run a cleaning disc through the transport at home if you want. My experience has been that CD players are a lot less problematic than changers, and there are a lot of thrift-store bargains in quality players from NAD, Denon, Yamaha and others.
Speakers are also easy to check since problems or damage is generally visual. Of course you’ll spot rotted surrounds and dented dust-caps right away (careful massaging and sometimes gum can pull out the latter). Gently pushing a woofer in and out can tell you if there is any voice-coil damage (you’ll hear rubbing).
Keep in mind that if you find a pair of higher-end or collectable speakers with rotten woofers for five or ten bucks, the enclosures, tweeters and crossovers are worth many times more than that. Moreover, woofers are relatively easy and inexpensive to replace. The Mordant-Short monitors I picked up had a bad woofer, in fact. Madisound Speaker Components (www.madisound.com ) had a decent inexpensive replacement that fit my $6.00 speakers, so I ended up investing just over $30 for a pair of nice British mini-monitors, albeit modified ones. Parts Express is another good source for replacement speaker components and parts (including grille cloth and hardware) if you find a thrift-store fixer-upper. www.parts-express.com
Of course, if you stumble onto a pair of classic JBL’s or similar in a thrift shop you can consider having the drivers reconed. It may be worth the investment since you’ve spent practically nothing on the original speaker. Madisound and other on-line speaker suppliers do reconing. There are specialists who handle certain brands. Human Speakers in New Hampshire, for example, specializes in EPI speakers and other quirky New England brands http://www.humanspeakers.com/human/index.html . Many pro-audio shops have on-site reconing and can handle consumer speakers.
Among the rack-system and multi-media speakers littering thrift stores are some real finds. The NHT SuperZeroes [above left] were $4.00 for the pair at an independent thrift. The ADS L300’s were $20.00 at ValueVillage. One ADS was still hiding in the back roomâ€”it pays to be persistent and be friendly with the staff.
From high to lower end, receivers are worth checking out.
Yamaha’s R-900 was the flagship of the brand’s first digital receiver line in 1980. More interesting to me was that it has two features also found in the initial Carver audio line of that same period: spatial expansion circuitry and radical, ultra-efficient power supply technology. This example from ValueVillage was almost perfect, with just a small chip in the rosewood-veneer cabinet.
One odd thing is finding multiples of the same audio component models. So far I’ve found four of these Hitachi HTA-3000 receivers, part of their digital-tuner “slimline” series in the early 80’s. Hitachi must have been a “push” line for a local audio retailer then. While not glamorous, these solid 40 WRMSx2 platforms are great for running a second music zone or light commercial system, and at 15 bucks it makes sense to have a spare. One is sitting in a kitchen cabined driving a pair of outdoor speakers on the deck on the other side of the wall.
Stay Tuned for Part 3 of this article –
Cleaning and touch-up
Before 27 years in corporate marketing roles for Xantech, Leviton, Carver, Harman/Kardon-JBL, and Bose Corporation, Mark Cerasuolo worked in audio retailing going back to part-time jobs in college. A lot of his audio “new finds” in thrift stores are old friends he couldn’t afford way back when. In 2010 he became the “first fully online undergraduate student to deliver a student commencement address at a traditional four-year college or university” at the University of Massachusetts in Amherst, proving that one can drop out to pursue an audio retailing and marketing career and still have it work out in the end. Mark is active in CEA, most recently with the Multi-Room Audio/Video group. He lives in Redmond, Washington, with his lovely and understanding wife Dawn.