Buying a Tape Machine: An 11-Point Checklist — from “Midnight Bob” Shuster

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Tape is still in high style in the audio world. Like a 1957 Corvette or a standup Pac Man machine, some technical pleasures never go out of fashion.

"Midnight Bob" Shuster has been maintaining tape machines professionally since 1975.

“Midnight Bob” Shuster has been maintaining tape machines professionally since 1975.

Although 99% of today’s audio facilities have a DAW as the center of operations, an element of analog tape processing remains a welcome element in a large number of studios.

While many engineers are content to approximate the sound with the wide array of tape-emulating plugins currently available, there’s no shortage of recordists willing to go hard-core with an actual tape machine on hand.

The problem for engineers, producers, studio owners, and archivists who have their heart set on obtaining a tape machine – whether it’s their first or is complementing one or more machines already in-house – is that there are virtually no new models on the market. Save for the Otari Mx5050 MKiii, which is still being made on a limited but costly basis, people who want/need tape will have to obtain a used machine.

So how do you know if that shiny Studer A827 24-track 2” machine that you’ve just discovered for sale on Craig’s List is your dream machine, or a lemon?

One man who can tell quickly is “Midnight Bob” Shuster of Long Island-based Shuster Sound, who stands among the country’s most experienced audio techs. A professional maintenance engineer since 1975, Shuster kept all the gear humming at top NYC facilities including the Power Station, Media Sound, Record Plant, Electric Lady, Sony Studios, Pomann Sound, Avatar, NBC, and many more.

Today, Shuster’s clientele has grown to include an ever-expanding list of solo studio operators and engineers, as well as radio stations, who count on him to keep their analog gear running strong. Tape machine repair and maintenance can account for several of Shuster’s house calls each week, and while some of the newly-obtained Ampex, Otari, Studer, MCI and Scully machines he sees are running clean, others would be more useful as retro coffee tables.

“NYC remains a hotbed of recording, and tape is enjoying a renaissance,” Shuster says. “I’m seeing that up-and-coming engineers, the old-timers, and everyone in between are discovering ways to combine the new and old. And people are saying, ‘I want an analog tape machine, because I know that it can make my record sound better.’”

If you’re thinking of adding a vintage tape machine to your palette, then you need to know what potential pitfalls to watch out for while shopping. Useful maintenance tips are here as well, for those who take the plunge.

Be sure to equip yourself with this essential checklist, as explained by Bob Shuster:

It’s the Heads

The tape heads of a Studer A820. (All photos by Bob Shuster - click photos to enlarge)

The tape heads of a Studer A820. (All photos by Bob Shuster – click photos to enlarge)

A tape machine is only as good as the condition of its tape heads.

Tape heads are the devices responsible for directly recording and playing back the magnetic pattern to or from the tape.  Just like a phonograph stylus on a vinyl record (OK, I’m dating myself here), or a microphone, they are transducers.  If a head is corroded, rusty or pitted, it will have an effect on the ability to accurately transfer the sound to a magnetic imprint on tape.

Heads can either be relapped or replaced. Relapping is a process of returning the original contour to the face of the head. This is done through a highly refined process of compounding and polishing the head by a skilled specialist.

Re-lapping is obviously the most economical choice, and most headstacks can be relapped between one and three times (depending on the amount of wear on the heads each time). A good test for a worn head is to take your fingernail and run it along the upper or bottom edge of the head — if you can feel a ridge or your nail catches on a ridge, it is a good idea to have it inspected for possible relapping. The exception to this would be an “undercut head” which actually has grooves cut just above the top and bottom of the head cores to help reduce edge wear and protect the tape.

To those unfamiliar with headstacks, it is difficult to explain the differences between head wear and intentionally undercut heads, but it is most easily explained that the undercut head has wide machined grooves which is easy to see. If the head is not undercut, it should have a completely smooth surface and your nail should not catch on ridges. You may also see uneven patterns across the face of the head.  Badly worn heads will have grooves at the top and bottom where the tape has travelled and causes level inconsistencies and can even damage the tape.

Another indication of bad heads is that they may not play or record at all and they may be worn beyond what relapping can repair. If you’re not sure about you’re seeing, call somebody in to do an evaluation. If you’ve purchased the deck already, have the heads taken off the machine and send them down to John French of JRF Magnetics in New Jersey – he’s the legend as far as saving tape heads. For illustrations and further information about heads and relapping, visit JRF Magnets at

If it’s too late for relapping, then replacement heads are the ultimate step, but that’s considerably more expensive.

The Tape Path

The tape guide roller of a Studer A820.

The tape guide roller of a Studer A820.

Next, take a look at the tape path: the reel spindles, incoming guides, impedance rollers, capstans, tach roller, tension arms/rollers, lifters and pinch roller.

Reel Spindles:  hold and secure the reels of tape on the machine

Incoming and Outgoing Tape Guides:  provide proper positioning of the tape across the heads

Impedence Roller: smooths the tape as it comes off the reel before reaching the heads (See “Image 1” in the gallery following the article)

Lifters: guides that pull the tape away from the heads in fast wind modes to prevent unnecessary wear on the heads. Lifters can also be released for fast wind audible cue. (See “Images 2 & 3” below)

Capstans: provides the precise speed to drive the tape past the heads. Rotational speed and diameter of capstan shaft determines the speed. Most capstans shafts have a dull finish. When they become too polished or shiny, they may cause tape slippage and speed errors. The capstan should be able to be rebuilt or refinished by a specialized motor rebuilding service. One such company is MDI Precision Motor Works, visit at http://www.precisionmotorworks. (See “Image 4 & 5” below)

NOTE: There are two disclaimers to the polished finish “rule” about capstans. There ARE some designed to be polished or shiny. The best way to determine if your machine’s parts were designed as such is to check the entire length of the shaft. If it is uniformly polished, it is probably designed to be so. Other capstan shafts are made from ceramic material and wear out very slowly, if at all. They are white in color.

Pinch Roller: rubber roller that provides proper tension to the tape against the capstan, permitting tape to draw off the supply reel and past the heads at a constant speed. If the pinch roller becomes gummy or cracks, it should be replaced or rebuilt. One of the rebuilding companies I use is Terry Rubber Rollers, at

Tach Roller:  (found on more advanced machines) Used for tape read-out/time counter and also monitors the direction of the tape and its speed for transport control. (See “Image 6” below)

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  • Lou Holtzman

    24 trk on 2 will always remind me of the scully 1 inch 12 trk. A raging flop. Nothing like my 1 inch 8 trk head stack.
    So goes 24 trk stack,nice but lacking.
    Now,16 on 2 was the sound. Just what analog was all about.
    Maybe I will pull that 24 out of storage and remove the 24 stack and put John French’s wonderful 16 stack back on.
    Any of you kids no how to align a machine?
    Lou Holtzman
    EastSide Sound NYC

  • Lou Holtzman

    Oh, let us not forget the AES of 1979 ,TAH DAH, introducing the MCI 32 trks on 3 inch tape. Interns had to be physically fit to carry the tape reels. Oh, what a bizz.

  • Bob Shuster

    The great MCI 32 track 3″ format that never happened. Saw that at AES in NY at the Waldorf Astoria Hotel. Had 3M mock-up reels with 3″ tape. We figured a 14″ reel would weigh in around 25 -28 pounds! Try and spin with that…try carrying it! MCI also invented a new speed for the format – 20ips! it never happened and wasn’t necessary to mention. There was 2″ 32 track Otari and Telefunken and the famous Stephens 2″ 40 track. They hung in there for a while, but never really caught on in the mainstream studio biz.

  • Gee Genet

    Glad to see someone putting a spotlight on tape machines.I still use my Otari Mx 5050 8Hd machine i bought new,a Mx5050 4track, and a studer Revox 2track for mastering.Great article!!!!!

  • Bob Shuster

    Hi Gee, Thanks for the nice compliment on the article! It’s about time something was said about this great format and give its proper due time in the spotlight. Glad you enjoy it!

    Best, Bob Shuster

  • Timheile

    Awesome article Bob….thanks so much. I used to work at the Record Plant in Sausalito with Manny:) went on to help put together the P&E wing of NARAS in later years:) Lou mentioned the 16 on 2… ever come across those? Would love to find one in good shape if you have any leads. Thanks again.

  • Bob Shuster

    You’re welcome, glad you enjoyed the article! Will keep a 16 track 2″ in mind for you when one becomes available.


  • Steve @ Sonicraft A2DX Lab

    Nice article, Bob! Great stuff. Hope you post this on your website where folks can find it indefinitely.

  • Alan Garren

    Nice overview, so many new people buying these great machines, So little knowledge in circulation among the new prospective buyers.

    One item however, RMG is now made in France outside Paris by Pyral, I have had tape from the new plant and it has performed well. I don’t know about Zonal being in business, although Canford still list it in their catalogue, no price I could find though.

  • Playground estudio

    Great article Bob!
    We have a Studer 16ch, 2″ A80 MKI running with Clasp in our studio @ Madrid.
    Great sound!
    All caps were refurbished and had a complete coming back to life by
    Thomas Lefevre in France.
    Very good professional and nice guy.
    Thanks for all the info.

  • fmdcer

    Hello Bob, thank you for your posting your informative guide. It was not a top-of-the-line machine but one that I could afford as a teenager: a Roberts 771X (transistor). I enjoyed using it for many years but eventually had to sell it (broke my heart) as I was unable to source replacement heads as they were metal. I don’t know when the more popular glass-ferrite heads came out but the metal heads were the downfall of this 66 lb boat anchor. Yet, it was a remarkably solid and accurate 4 speed machine (1 7/8, 3 3/4, 7 1/2 and optional 15 ips). I dragged that thing to my band practises and shows. Before the quality dergaded any further, I copied most everything to cassette and finally to computer. I am now looking for another r2r deck as I’ve really missed having a machine for some +30 years now, time to get another one…maybe an Akai…

    Ben from Canada

  • Idiot

    I was exactly what my DISQUS name states, when I gave my deck to Bob for repair. After month of broken promises I got it back in the same state as I brought it in. Broken. At least he did not charge me for storage.

  • Bob Shuster