Analog Tape 101

Analog Tape 101
PART ONE

by Eddie Ciletti

THE TECH’S FILES

Since 1995 I’ve focused on the repair of digital tape machines—4mm, 8mm and S-VHS—but it wasn’t always that way. Recently, three projects jolted me back to my roots. A man gives his son a Tascam 80-8, a church wants to digitize 40-year-old sermons, and a live Joni Mitchell recording (from the Main Point in Philadelphia some 30 years ago) recently arrived in the mail. These are reasons enough to compile some data and take out my digital crayons…

Meanwhile, neophyte analog freaks are scouring online auctions such as digibid.com and ebay.com for pro and semi-pro classics. Unless they understand what they’re getting into, I am afraid for them. Whether you already own or are thinking about buying an analog tape machine, it is important to know the maintenance issues, especially for that most expensive wear item, the headstack. A deal is only a deal when you are capable of smiling after the selling price is mated with the maintenance cost. Tape machines have lots of electromechanical moving parts that wear out or get funky, even from lack of use. If your budget is large enough for “piece of mind,” Otari still manufactures the MTR-90 III multitrack and inventory remains from Studer’s final production run in 1999.

GEN-FLUX
I’ve made one very broad assumption for this article, that a new generation needs to become familiar with the nuances of analog recording equipment—pro and semi-pro—including tape and the effects of aging. The dividing line is track density: 24-track translates into three tracks per 1/4-inch; semi-pro is four to eight tracks per 1/4-inch, referred to as “narrow format” in this article. A table will be provided in Part Two.

Part One will focus on analog idiosyncrasies, how to assess the machine and what to do when the VU meters are dancing instead of standing at attention. I will barely scratch the surface of alignment preparation before running out of space in this issue. Part Two will cover electronic and mechanical alignment. For a list of test equipment, check out the May 2000 issue of Mix or go to www.mixonline.com. At minimum, you should at least have an oscillator.

MOVING THE MOUNTAIN
Few project studios can boast a full-time technician—let alone one with analog tape machine experience. Fewer experienced technicians are willing to make house calls because older professional machines need an overhaul, not a tune-up. You should establish a healthy relationship with technical support personnel; they are human beings, after all, performing a service that is a labor of love with skills that are becoming exceedingly rare.

There are several third-party companies providing analog machine support listed in the “Selected Analog Recorder Parts/Service Resources” sidebar. Some, like ATR Service, will even send a shipping container. For example, an Ampex ATR-100 shipping crate is $225 (an additional crate for the pedestal is $75). Empty crates are shipped via UPS. Cargo Inc. (www.cargo-inc.com) will ship an ATR coast-to-coast for about $300 (insurance will vary). An Ampex MM1200 crate is $475; shipping is about $600.

On the upside, analog machines will continue to be serviceable—now, after 20, 30 or 40 years and in the future—because they mostly consist of hardware that any skilled machinist can re-create. (No digital format will be as easy to support after manufacturers throw in the towel.)

CONSUMER ARCHIVE
On the consumer side—for the quarter-track stereo format, at speeds of 7.5 ips and less—your only option is to find a good used machine. The Revox A77 and B77 are both excellent choices as are the Technics 1500 and the Otari 5050 series. All are three-motor decks with 10-inch reels available in speeds from 3 3/4 to 15 ips. If you need a machine that runs at 1 7/8, consider the Tandberg 9000X, which has three motors, 7-inch reel capacity and speeds up to 7.5 ips.

KEEP YOUR MACHINE HEALTHY: SOME SUGGESTIONS
Tweaking open-reel tape machines triggers a list of “things to remember.” Here’s the first batch:

1. When threading, make sure the tape is snugly wound around the reel hub before pressing Fast Wind or Play. (Careless threading leads to stretched tape, bent or broken guides.)

2. Use water-based cleaners on rubber parts. Do not use stuff that says “rubber cleaner” unless you are sure it is water-based. Windex and Fantastic do a good job. Formula 409 works well on ceramic capstans. Don’t let any cleaners or solvents get into the capstan bearing. Dilute if necessary.

3. Always observe the tape as it passes through the guides, over the heads and between the capstan and pinch roller. Tape should not be riding up and down or buckling where the edges meet the guides. You should not be able to see the “edge tracks” of the head.

4. Use 99% anhydrous (or denatured) alcohol to clean the heads in strong light. Do not use rubbing alcohol because it’s 30% water.

5. Keep tweakers (fiddlesticks) in pocket protectors unless chaperoned or until you feel extremely confident.

6. Demagnetize your tools.

7. Odd behavior may be attributable to the machine, but never rule out the tape. Since the ’70s, high-output tapes have been prone to shedding. Always inspect the heads and guides before calling a technician or grabbing a screwdriver. The biggest challenge, even for veterans, is not realizing a tape has deteriorated before carelessly winding end to end. Visit my Web site, www.tangible-technology.com, for an article on tape restoration.

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