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It Came In a Box With a Hole


Shop life might be predictable in the service department of an equipment manufacturer or major retailer. But in my reality, what may arrive at any given time can defy all expectations. Even with notes, there are times when gear I thought I knew tests my skills. Here’s a blog of the highs, the lows and the midrange.

Figure 1: A UREI 1178 arrived in this box with a hole in it. The force was enough to dislodge the meters.

Figure 1 shows every repair facility’s worst nightmare. You could blame the carrier (and many people do), but this is the reason to double-box and make sure each box is well-stuffed. It’s fairly typical for the Modutec meters on this UREI 1178 (and other vintage UREI products) to get shaken from their moorings, but don’t be inclined to over-tighten the mounting hardware, which will only increase the possibility of cracking the plastic frame. (We often install rubber bumpers on the lid to keep the meter in place.) Fortunately, no serious damage was done — this time.

Rackmount DAT decks are still a popular choice in applications such as radio/video production and in mastering/preservation, when archiving/transferring audio libraries to disk media. Despite occasional transport issues, DAT recorders have at least one plus: As they have no fans, hard drives or monitors, they sufffer no whirs, whines or high-frequency hash. In the broadcast environment, they can reside in the control room or studio.

Despite all of the advances in location recording technology, DAT is still part of the equation, even if relegated as a backup. Six Fostex PD-4s and one PD-2 (all timecode portables) recently saw bench time. Many of the problems are due to cold solder joints, heat-damaged capacitors and something new-ish — flat cables that have flexed or creased one time too many. Very popular in manufacturing everything from DAT decks to consoles to laptops, these not-so-flexi ribbon cables save lots of space, but when they’re over-folded, they can create vulnerability. Note: Fostex no longer stocks this part, so I’m working on alternatives.

Also seated at the bench are various U87s, 414s, an RE20 and vintage classics such as an SM69 (a stereo U67 outfitted with a pair of AC-701 vacuum tubes) and two U47s. The 87s most often have dirty or punctured capsules from all those unnecessary vocal close-ups. (Always use a pop filter.) If the mic dies on a plosive, it is because the capsule has become sensitive to humidity and should be inspected by a professional.

Of the mechanical problems, two of the 414s had cracked frames (nice on drums but not as drums). Both the SM69 and the RE20 had lost a press-fit pin. On the former, the pin limits the upper-head’s rotation to less than 270 degrees; on the latter, it prevents the connector section from rotating. In both cases, pin failure allowed for damage to the internal wiring. It’s a classic case of a seemingly innocuous (yet still missing) $0.50 part leading to major problems and a big-time repair bill.

During the burn-in process, the SM69’s power supply also requested attention, eventually revealing the most typical ailment: hum from dried-out capacitors in the power supply circuit.

Figure 2: This BLUE-restored Telefunken U47 has a replacement KK47 capsule and an EF-86 tube.

Then a pair of U47s warmed up the joint — at least, once they were working. There was a noisy Telefunken version (Fig. 2) that was more BLUE than Neumann; its VF-14 had been replaced by an EF-86 that its current owner changed several times to no avail, blaming the mic for “eating tubes.” Inside, a solid-state section — designed to protect the original VF-14 from rude awakenings — decided it wanted to “improvise.” Unlike a vintage mic, documentation was not available. I got lucky, but not before blaming the power supply.

The owner of the other U47 feared the worst — that the World War II — era VF-14 vacuum tube had bit the dust and the mental gymnastics that go into the process of deciding what to do. Functional U47s with a VF-14 are both rare and extremely valuable — the more original, the better — but the VF-14 is more than scarce, selling for about $1k or more, if you can find one.

Modification to any of the alternative tubes is similarly costly. Sadly, it can also kill the mic’s value for those who own one as an investment. That’s not my MO, but I do understand that a modification often needs to be reversible. A mic or any piece of vintage gear comprises a handful of “precious” component parts — in this case, the capsule, the tube, the output transformer and even the grille each contribute a good 25 percent of the magic. And, of course, the sum is greater than the parts.

So how could a U47 with a functional VF-14 still exist in this century? A major reason is that the tube’s 50-volt filament runs at 35V. Operating at 70 percent of rated value obviously extends any tube’s life and this should be taken into consideration if a tech is replacing it with the pin-compatible EF-14, which has a 6.3V filament (70 percent of which is 4.41V). Using this tube minimizes, but does not eliminate, alterations to the mic and the power supply.

Like DAT, analog tape machines serve two purposes — archiving and recording — so there are several online support groups keeping the flux energized. Check out sony_apr at If you’re in the market for a used professional machine, then buy it from a company that specializes in restoration. Semi-pro/narrow-format machines are a whole other kettle of fish; “buyer beware” comes to mind. As a buyer, you must insist on better-than-average packaging. All analog machines are heavy and must be double-boxed with double- or triple-walled cardboard. Check out for options. Insure for the original purchase price.

Okay, call me anti-capitalist and all the associated “pink-ness” that goes with my leftist leanings, but I find the process of flipping — buying undervalued stuff and reselling for a profit — distasteful. Much of the vintage stuff on the Web is so in need of major TLC that raising the price only makes it harder for everyone down the line to do justice to the resuscitation process. Bringing the device into this century is costly (and therefore less likely) if the end-user paid too much and then judges the now-weary circuitry to be less than magical.

For all of the above-mentioned gear (and then some), the key ingredients to a successful restoration are time, patience and money. Time is required not just to do the work, but to make sure that all of the problems stay solved. We run stuff for a few days, cycle off for a few more, power up and then play with it for a while. Patience means never having to say, “I shouldn’t have rushed.” Sometimes, this means taking a whole front panel off just to be able to reinstall the meters without stressing the wiring and everything in the neighborhood.

And money — where would we be without that?

Eddie would like to thank Logan, his nimble-fingered assistant, along with all of the customers who keep his geek skills sharp. Visit
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