A very unusual tape recorder used for mastering

A very unusual tape recorder used for mastering

If you look at the photo carefully, you will see that this Studer A80 analog tape recorder has several more tape guides than the norm. It's used for mastering. But why?

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At the time of writing (June 13, 2012), this tape recorder is up for auction on Ebay. It is a Studer A80 and, as analog tape recorders go, this is one of the very best. But this isn't a normal A80, it is the mastering version. So the question is, why is there a special mastering version, and what makes it different from a normal A80?

If you look closely at this pic, you will see that the heads are arranged differently to a normal tape recorder...

Studer A80 mastering

Usually, you would expect to see three heads - erase, record and play - set very close together underneath a head cover that makes everything look neat and tidy. But here there are two playback heads, separated quite widely.

So this machine can't even record, so it isn't even a tape recorder - it is a tape playback machine. So how does that make it suitable for mastering?

The answer is that this machine was used for mastering to vinyl. It is only ever used to play back signal to a vinyl cutting lathe. It is not capable of recording and that never was the intention of the machine.

So now the question arises why a special version of the A80 was desirable for mastering? Why wouldn't a standard A80 do?

The answer to this is that to maximize the duration of playback of each side of a vinyl record, the turns of the groove should be spaced so that they never take up any more width than necessary. Loud signals make the groove wiggle a lot. For quiet signals the groove is much more nearly a smooth curve. Lathes were designed so that they could automatically modify the pitch of the groove according to the level of the signal. However, since a quiet section in one turn of the groove might be followed by a loud section in the next, the lathe had to be able to 'look into the future' to see what is coming next.

This is the purpose of the second 'preview' playback head on the left, which sends signal to the lathe's control mechanism a little ahead of the signal sent to the lathe's cutter head. The extra tape guides are there to extend the time interval between the preview head and the main playback head. The tape is looped around these heads according to the diagram attached to the top plate of the machine.

Of course you could say, "Why not use a normal tape recorder and delay the signal to the lathe's cutter head digitally?"

Tell this to a vinyl junkie and see what happens...

Publication date: Friday June 15, 2012
Author: David Mellor



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Earlier discussion on this topic...

Frank Kobina Prah, Cape Coast, Ghana

It good to have it but now the computerize world has made it difficult to come by this but it seems it okay
Wednesday June 20, 2012

Michael Fremer, Wyckoff, USA

Of course machines like that are still in use today as vinyl has made a big comeback (sounds better than any digital format in my opinion and in the opinion of many recording engineers too--like Roy Halee who recorded "Graceland" and all of the Simon and Garfunkel albums, Dylan's "Highway 61 Revisited" etc. so he knows what great master tapes sound like)...Sterling Sound has one, as do other mastering houses that produce all analog lacquers for music recorded in the analog domain. If you listen to Ray LaMontagne albums, all of them are AAA all the way. That's how Ethan Johns insists they be made. Digital preserves music the way formaldehyde preserves frogs: you kill it, and it lasts forever. Although not even the "forever" part is true.
Wednesday June 20, 2012

Don Norman, Kingston, Canada

Ah ha! I'm the fortunate one who has lived in both worlds. I was in RCA studios in Montreal and Toronto in the days when the tape machines were the size of a telephone booth. Oh sorry, some of you are too young to know what a telephone both is. No sliders on the very small mixing board either. I could go on and on but the point I really want to make is; how thankful I am to have lived long enough to work with today's technology. Performing, studying and recording music keeps this old boy going.


Wednesday June 20, 2012

Henry Diaz, Shirley, United States

I think it's a testament to the ingenuity and persistence of audio engineering of the era. The techniques devised to squeeze the best performance and fidelity of what state-of-the-art equipment was available at the time never ceases to amaze me. Of course today many of past audio hurdles have been "solved" (debatable) by the digital revolution but after all ... how did we even get here? Through generations of audio enthusiasts searching for improved methods of recording, editing, mixing, mastering & distribution. If you compare yesterdays "best" recording to today's "best" you must admit that the bar has been raised and some extremely good audio tools are now available to nearly anyone who has the ability to use them well (and some "not-so-well). So be grateful to audio's past efforts and the fine moments in music regardless of how they were captured. And think about this: Just what will be considered "ancient audio arts" 50 years from now?
Tuesday June 19, 2012

Wayne, Nashville Tn, USA

Ah the good old days. When recordings actually sounded good, unlike today.
Tuesday June 19, 2012

Joe, Philadelphia, Pa

Yes indeed, just another example of the insane hoop-jumping we had to do back in the "good old days" to stuff great audio into so-so vinyl grooves. ;-)
Tuesday June 19, 2012

Jack, Peterborough, Canada

It is one amazing looking part of music history. I would Concider buying it just to have in my Studio.
Tuesday June 19, 2012

Lemon, -, -

When i see this im so happy we are in the digital era.
Just a small curse from my side in the audio-recording church :)
Tuesday June 19, 2012