Hands On: Revox B77 Master Recorder (SOS Aug 91)

The Revox B77 and the Sony DTC1000ES are the world’s two most popular master recorders. Am I making a contentious statement? Do I risk the wrath of those who would say that nothing less than a Studer or Otari reel-to-reel or top-of-the-range Fostex or Sony DAT will do for serious stereo mastering for CD release or broadcast? The true figures are probably impossible to obtain, but I would say with a good deal of confidence that, considering all levels of studio activity, the B77 and DTC1000ES has each recorded more masters in its respective format than any other machine.

A catalogue I have before me (from Canford Audio) has space to list only six of the 67 versions of the B77 which can be supplied to special order. The Sony DTC1000ES isn’t as common as the B77, and probably never will be due to the proliferation of new DAT models coming onto the market, but it has the distinction of having being accepted as the recording industry’s favourite in these early days of DAT.

These are the two machines that we’ll be looking at in this and the next installment in the Hands On series, starting this month with the B77. The idea is not so much to help you in your purchasing decisions as to provide helpful advice for those who haven’t yet had the pleasure of operating either the B77 or DTC1000ES (or any reel-to-reel or DAT machine, for that matter), but would like to know what to do when the opportunity comes along — as it always does sooner or later for those who are really determined to get into serious recording. However, if you are in the market for a stereo recorder, you won’t regret buying either of these machines. I can say that from my own experience since I’m lucky enough to have both in my personal studio. (Actually, my reel-to-reel is a Revox PR99 Mk I, but this is essentially a B77 in wolf’s clothing, with a few extra ‘professional’ features for ease of use).

The combination of reel-to-reel and DAT is ideal for me since I can master simple tracks directly on to DAT, and if editing is required I can go via the Revox with only a small quality loss. If by some misfortune it happened that I had to re-equip my personal studio, I would go straight out and buy the same machines again, so you can take that as a strong recommendation for both.

POPULARITY

There are two principal reasons why the Revox B77 is so popular: it gives a good audio performance; and it is very hard wearing. My PR99 sounds as good as when I bought it eight years ago. Another reason might be that Revox don’t change their models every year, so spare parts are available to keep the machine going on and on. The only major drawback to the B77 is that it was conceived as a domestic machine for use as part of an expensive hi-fi set-up. This means that it isn’t as easy to use as it might have been, and there are features which do not find application in the recording studio and which can cause a certain amount of confusion (the PR99 corrects this deficiency, but at a much higher price).

I’m going to assume here that the reader of this article hasn’t used a reel-to-reel machine before, and go through the basic operation of the B77 from first principles. If you are already fluent in handling tape recorders then you have probably forgotten how difficult it was to thread your first reel of tape. I haven’t — even though it was much longer ago than I care to remember.

So this is the big moment: you have the opportunity of using a stereo recorder of professional quality for the first time. What’s the first thing to do? Actually, the first thing is to be aware of the B77’s weak points: the front panel switches. These are weak in both the functional and physical senses I’ll get on to the functional problems later, but for the moment let me advise you to take care when carrying the B77 from place to place. It’s very easy to knock the protruding switches and break off the levers. I have seen it happen many times. If you are lucky, a short stump will be left behind and the switch will still work. Once the machine is where you want it, you need to connect it up, if it isn’t ready to go already. The mains cable is an unusual type, similar to a standard IEC cable but with a 2-pin connector. This isn’t a problem unless you lose the lead — there are usually plenty of standard cables knocking around any studio, but only one cable for the Revox.

The audio connections are via phono sockets. There is only one pair of output phonos, but be sure to connect the input to the machine via the sockets labelled Aux Input. While you are looking at the rear of the machine, check whether you have a NAB or IEC model (this will be indicated close to the connector panel). Make a mental note of this for later. Once you have the machine connected, lay it down horizontally. It will work perfectly well in the vertical position, but it isn’t as easy to use.

With the machine powered up (I don’t have to explain how to do that!) you’ll need a reel of tape and an empty spool to start recording. One problem with analogue recorders is that they have to be aligned to the particular type of tape you want to use. High end studios with mega-expensive reel-to reel machines will check the alignment on each batch of tape (or sometimes even on each reel) to get best quality they possibly can. Alignment isn’t as much of a problem as it used to be, since virtually every studio in the country uses Ampex 456 tape, which is very consistent, and other tape manufacturers have been forced to produce tapes which will work with the same alignment so that they can hold on to their share of the market. Ampex also produce a type 406 tape which is cheaper, and has certain advantages, but needs a different alignment. If more than one type of tape is available, then you’ll have to ask the machine’s owner which type it is aligned for. This is an important point because if you use the wrong type of tape then you will get vastly inferior results.

There are several types of spool on which the tape may be wound. The usual type is the 10.5″ metal NAB spool which holds just over half an hour’s worth of tape. To use these, you need a pair of NAB adapters which fit on to the B77’s cine spool mounts. Revox, for some reason, always pack a plastic 10.5″ cine centre spool with their machines. The only practical difference between these and the NAB spools is that if you are foolhardy enough to use your fingers to help brake the spools in fast wind you will probably live to tell the tale with metal spools (don’t take this as an encouragement), but with plastic spools you’ll get your fingers burnt — literally.

Plastic 7″ spools are also fairly widely used, and they come in two types: those with a small centre hub diameter and those with a centre hub as large as that of a 10.5 NAB spool. Both types have cine centres, and therefore do not need NAB adaptors. The B77, it has to be said, doesn’t always perform at its best with the small centre spool. When the reel comes close to the end, the back tension can slow the tape down in play or record modes which obviously isn’t desirable. B77s in prime condition are unaffected but well-used machines often have difficulty, so it’s better always to use large centre 7″ spools even though they don’t hold as much tape.

Threading the tape is easy with practice, but difficult for the first timer. Fairly obviously, the full reel goes on the left hub and the take up spool on the right. Flip down the metal cover which hides the tape’s path (or better still, unscrew it and throw it away) so you can see the straight-line path that the tape must follow. The main thing to remember is that the tape must press against the tension arm. This applies to all tape recorders — the tape must press against the tension arm or roller and displace it from its rest position.

If the take up spool is a 7″ type (it must be the same size as the supply spool or the tape may be damaged when stopping after fast wind) there will be a slot into which you can thread the tape by turning the oxide (brown) side upwards. Allow about an inch to protrude as you turn the spool by hand until there are a couple of full turns on the spool. Once the tape has ‘taken’, you are ready to put the machine into play or fast forward. It’s always important to remember with any machine that if the tape isn’t firmly attached to the take up spool, when you press play the reel will spin very quickly and the tape may grip suddenly and bend the tension arms. The procedure with an NAB spool is the same except that there is no slot in the spool to help you, so hold the tape on to the hub with your finger as you turn the spool.

A frequent error — the tape must be in front of both tape lifters

Correctly threaded tape on a Revox PR99 (a version of the B77).

Threading the tape is easy with a little practice, but one problem that can occur is that the tape doesn’t move when you press the play or wind buttons. This is often misinterpreted as a machine fault. The photos of my PR99 with the head cover unclipped show what’s wrong. Newcomers to the B77 have this problem more often than you would believe.

B77 CONTROLS

With the tape correctly threaded you need to check that the spool size button (under the metal flap) is in the correct position, and make doubly sure that the Varispeed control (also under the flap) is most definitely switched off. You can guess what will happen if you make a recording with the tape running at the wrong speed. Moving downwards, the controls fall into two groups: output controls on the left; and input controls on the right.

The output controls consist of the Input/Tape selector switch, the Mono/Stereo switch and the output level control. The important thing to remember is that these controls affect the output only, not the recording. The Input/Tape switch allows you to listen, via headphones or the line output, to the input signal to the recorder or to the output from the tape. With the tape stationery you must have this set to Input to hear anything. When the tape is playing, it must be set to Tape. When recording, you will set the levels with Input selected, and when the tape is running switch over to Tape so you can monitor the recording off the playback head. The Mono/Stereo switch is very versatile, and lets you listen to the left, right, stereo, mono or reverse stereo signals. Remember that this control does not affect the recording.

Over on the input side, there is an input selector switch to be set correctly. This will nearly always be in the Aux position. The Radio, R>L, and L>R settings are not relevant to the professional user. The mic inputs can be handy sometimes, but the quality is not as good as you can achieve by going through a mixer. Now let’s go over in depth the most important part of the process of tape recording — setting the levels…

The B77 is equipped with a pair of VU meters. It’s often said that the letters ‘VU’ stand for ‘Virtually Useless’ and this is true to a large extent. The needles on a VU meter respond very slowly, so fast transients will not register properly and may create distortion on the tape. Fortunately, the B77’s meters also have peak LEDs which illuminate when the level reaches +6dB, which is the point where distortion just starts to become noticeable. You should set peak levels using the LEDs, which should flash on and off during the loudest sections of the programme. If they are on solidly, then the level is too high. If they never, or seldom, come on; then the level is too low. As a rule of thumb, I allow the LEDs to illuminate for approximately 20% of the time during the loudest sections.

The meter needles themselves are still useful, even though they don’t read true peaks, for checking that the levels are the same in both channels. This is an important point, and you should take care to match the levels as closely as possible. As I said earlier, levels are set with the Input/Tape switch set to Input.

To arm to B77 for recording, set the Record Ready switches on both channels to Ready. Starting recording is no problem, as long as you remember that it takes just a little time for the tape to come up to full speed. Press the Record and Play buttons together, and count to three before your sound source, whether live performers or multitrack tape, starts up. If you monitor your recording with the Input/Tape switch set to Tape then you can hear the sound coming off the tape itself, a fraction of a second after recording, so that you can check the level with your ears. If it sounds clean and undistorted then all is well. Remember when you play the tape back to set the Record Ready switches to Safe so that there is no possibility of erasing something you want to keep.

I have already explained, in my Recording Techniques series, what to do with the tape after you have recorded it, but by now you have enough information to make a start with the Revox B77 and operate it with confidence. The few points I haven’t mentioned are easy enough to work out for yourself, and when you’re ready for more advanced work with tape then you will probably need someone to show you what to do. The B77 is a good machine and with proper handling it will easily produce a recording of master quality.

FURTHER INFORMATION

Revox UK, .

REVOX B77 HINTS

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To ensure the best sound quality, always use the highest tape speed available (and to hell with the cost!).

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Recording doesn’t take place unless the red lights come on. The design of the Record Ready switches is such that dirt can get in and affect their operation — so you could be switched to Record Ready yet when you press the record and play buttons no recording takes place. Flip the switch a couple of times to cure this. Always check for the red lights when you are recording.

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The end-of-tape sensor is sometimes a little over-sensitive, and the machine may consequently stop on a white leader. Most B77 users fix several strips of splicing tape over the detector (to the left of the erase head) until the correct sensitivity is found. A crude solution, but it works.

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The editing scissors are handy for cutting the tape, but the plastic block is not so good for joining it back together with splicing tape. Many B77 owners attach a proper splicing block to the head cover.

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All stereo recorders come in NAB or IEC versions (except more expensive switchable models). These descriptions refer to the amount of high and low frequency energy recorded on the tape, and the amount of correction needed on replay to make the frequency response flat. A tape recorded on a NAB machine will sound best played on another NAB machine, and vice versa. Find out which standard the machine you are using is and label the finished tape appropriately.

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Don’t forget to clean the heads with isopropyl alcohol before you start!