Inside Track: Reel-to-Real

Posted on 17th December, 2019

Inside Track: Reel-to-Real

Thanks to the recent vinyl revival, ever more people are realising how sublime analogue music can sound – even when compared with so-called studio master-quality digital formats. And now another analogue format is coming back into fashion – reel-to-reel tape. The purest way to enjoy music is to keep it in the analogue domain in its journey from instrument to brain, and tape can sound even better than the mighty vinyl LP.

When the first Compact Disc players reached consumers in 1982, the slow decline of analogue sound reproduction began – and by the beginning of 2000, CD had largely replaced LP and Compact Cassette in most developed countries. Yet some people refused to stop believing that analogue had something that digital didn’t. 2007 saw an upswing in vinyl sales, and we haven’t looked back. One decade on, the same started to happen for another analogue format – open reel tape. It can be expensive to get into, but the potential sonic rewards are so great that many audiophiles have embarked upon this journey. Keeping the music in the analogue domain in the purest possible way, gives results like nothing else you’ve ever heard.

PAST TIMES

Sound recording was invented back in 1860 by a French printer called Édouard-Léon Scott de Martinville. Although he successfully devised a mechanism that drew sound waves as a wiggly line on a piece of paper covered in soot, he didn’t have any way of playing the recording back. Some ten years later, American inventor Thomas Edison took the concept a stage further by recording the sound waves as a physical displacement of a groove on a record – firstly as a vertical ‘hill and dale’ displacement in a groove cut into a wax cylinder, then as a lateral displacement of a spiral groove cut into a record. In parallel to this, Danish engineer Valdemar Poulsen invented the wire recorder in 1898. This magnetised a fine wire passing over a record/replay head. However, the sound quality meant that it was only really suitable for dictation. They were in general use from approximately 1946 to 1954, when magnetic tape took over…

In 1929 a German, Fritz Pfleumer, patented a magnetic recording tape using oxide bonded to a strip of paper or film. Building upon this, AEG developed the Magnetophone, and its partner BASF produced the first magnetic tape in 1935 using a cellulose acetate tape coated with a lacquer of iron oxide. As the audio quality improved, domestic tape recorders started finding their way into homes, so people could make their own recordings of radio broadcasts.

After World War II, developments in magnetic tape recording and a demonstration of the Magnetophone in the US came to the attention of Bing Crosby – who decided to invest $50,000 in a little start-up tape manufacturer called Ampex (the name comes from the initials of the company owner Alexander Matthew Poniatoff, plus ‘excellence’). Crosby was one of the first to use tape to pre-record his radio broadcasts and the first person to master commercial recordings on tape. Apart from being able to edit radio performances by cutting and splicing the tape, it was also possible to make master recordings and then use them to cut the master lacquers for pressing records. This was due to the high quality of magnetic tape recording and the ability to make multi-track recordings that could be mixed down to single-track mono or two-track stereo.

STANDARDS

During the nineteen fifties and sixties, tape recording took off in both professional and domestic markets. Pro recording focused on audio quality, while domestic recording was about getting the most out of your investment in the tape. Speeds were established in order to get the best quality for a given application; 15IPS (inches per second) was the speed of choice for professional music recording and radio programming as it gave the best audio quality across the audio spectrum. 30 IPS produced the best possible treble response and lowest noise-floor – however, in most cases, this was also unfortunately at the expense of the bass response. 7½ IPS was the highest domestic speed for hi-fi recordings and, also the slowest professional speed. 3¾ IPS was the standard domestic speed and 1 7/8 IPS was the slowest for long duration speech recordings. However, improvements in tape manufacture meant that 1 7/8 IPS was adopted for Compact Cassette, and offered surprisingly decent audio quality.

Given the higher speeds used in the professional arena, larger tape spools were required compared to the domestic market. Usually, 10½ inch or 12-inch spools of tape were needed to hold sufficient tape to accommodate a reasonable recording time. For the domestic market, cost and portability were key issues. Spools were already available for the ‘home movie’ market and these spools – which were able to hold 8mm movie film – could also be used to hold quarter-inch audio tape. So, audio tape was sold on 3 inch, 5 inch and 7½ inch spools. These spools had the trident ‘cine’ centre holes and domestic tape records were designed for use with these fixings. Generally speaking, a larger centre hole was better suited for professional use and the NAB (National Association of Broadcasters, in the US) centre was adopted.

Another difference between domestic and professional tape is the track width on quarter-inch tape. Professional mono tapes are unidirectional and the track occupies virtually the entire width of the tape. Professional stereo tapes are also unidirectional and have two tracks on the tape. Domestic tapes are bidirectional and mono recordings occupy the top half of the tape. This means the tape can be turned over at the end, and used again for cost and convenience reasons – but the tape can’t be edited. When commercial stereo pre-recorded tapes first appeared in the fifties, they were issued in the professional format of two-track tapes ‘for in-line heads’, which means that the two channels were stacked vertically in-line (very early stereo tapes were recorded with staggered heads). During the sixties when stereo recordings for the home took off, tapes were four-track bidirectional, with tracks one and three used in one direction and tracks two and four for the other direction.

In order to minimise tape hiss and record the audio in the most efficient way, some frequency bands are boosted slightly during recording and others are attenuated slightly. The reverse process is applied during playback – this is called equalisation. There are two main systems in use for tapes – NAB (also called IEC2 - International Electrotechnical Commission 2) equalisation used primarily in the US and CCIR (‘Comité Consultatif International pour la Radio’, or IEC1) used in Europe. Both CCIR and NAB have their strengths and weaknesses, but it’s important to use the correct equalisation for playback of pre-recorded tapes.

GETTING GOING

Starting your adventures in tape does not necessarily mean investing heavily in professional equipment. You can experiment with domestic machines and purchase second-hand pre-recorded four-track stereo tapes recorded at 7½ IPS, which are readily available via internet auction sites. Used domestic machines are also readily available, and it’s not necessarily a complex or costly task to get them back to good working condition.

If you’re a newbie wanting a really gentle introduction to the world of analogue tape, then look no further than Compact Cassette. It’s a myth that they are poor quality because they’re recorded at just 1 7/8 IPS. Given the improvements in tape composition over the years, the sound quality can be truly remarkable – especially when you have a good cassette deck and play some of the new cassette releases around, from the likes of Chasing The Dragon in the UK, for example.

When looking to buy any tape machine secondhand, general cosmetic condition is a useful – if not foolproof – guide. Aside from how new the machine looks, inspect the tape heads and capstan for excessive wear.  Lines on the tape heads and a very shiny ¼ inch band on the capstan will probably mean that the machine has had a great deal of use.

When you get your machine home, the first thing to do is to give it a good clean. Pay particular attention to the tape heads and tape path (tape guides and tensioners) and clean them with isopropyl alcohol on a cotton bud. The rubber pinch roller will probably have a shiny oxide coating, but this should be cleaned off with detergent – do not use alcohol as this can damage the rubber surface.

Tape head demagnetisers are still readily available, and certainly worth using if you have a distant and/or muffled sound. Do make sure you use them correctly however, as they can actually end up magnetising the components or demagnetising your tapes! Switch the device on, holding it at about a metre away from the machine and then gently and slowly move it over the heads and guides without switching it off. When finished – with the demagnetiser still switched on – move it slowly away from the machine until it is at least a metre away before switching off.

If your machine has problems with rewinding the tape, fast forwarding or taking up the tape during playback, it’s likely that the rubber belts inside have perished and will need replacing. Replacement belts and available via online auction sites or from specialist suppliers. Although changing the belts is a little more involved and requires taking the front cover off the machine, technical manuals and videos explaining how to do this for popular machines are readily available.

All being well, you now have a working tape machine and can start building a collection of commercial pre-recorded tapes of your favourite music. However, you are not going to experience the huge improvement over vinyl, in terms of dynamic range, realism and imaging, without venturing into the world of professional tape…

THE PROFESSIONALS

There are still many used pro tape machines available today on the open market, but prices are steadily increasing as demand continues to rise. Brand new machines are also appearing but they are understandably quite costly; for example, the Ballfinger M002P playback-only machine is around £10,000 and the M063H5 recorder costs over £20,000. For many then, buying a second-hand machine and restoring it will be the option of choice.

Used ex-studio machines can also be purchased, and the same rules apply for assessing these machines as for a used domestic machine. Bear in mind however, that a studio machine will have had a lot of use. Prices range from £1,000 to almost £10,000 for a top, professionally restored machine. Many consider that the finest pro makes include Nagra, Ampex, and the Swiss company Studer (which also made the domestic Revox range of machines). To get the best from a forty-year-old machine, professional restoration will likely be required. This will typically involve replacement of around 200 components, mainly electrolytic capacitors, which is a job best left to an expert – such as The Audiophiles Clinic (http://www.theaudiophilesclinic).

CALIBRATION

Whichever professional machine you get, you’ll need to set it up correctly.  Each machine has its own calibration adjustments, ranging from potentiometers which you adjust with a screwdriver, to push-buttons when the machine has a microprocessor-controlled system. The procedure varies from model to model but will essentially involve adjustment of playback equalisation and head alignment. For this you’ll need a calibration tape from the likes of MRL; choose one for your chosen level of tape magnetisation (fluxivity), which is measured in nWb/m. A good standard to use these days is 320nWb/m, and you will usually need calibrations tones of 100Hz, 1kHz and 10kHz in order to calibrate the playback electronics and replay head alignment. You’ll also need a tone generator to calibrate the record electronics and tape bias (which will need to be done for each make of tape you intend to use), but this is not necessary if you only intend to play pre-recorded tapes. As ever, there’s plenty of further reading online…

PRE-RECORDED TAPES

Many open reel enthusiasts don’t bother with the recording side at all, preferring to use their machines solely as a high quality source component. This is getting easier because we’re now seeing a resurgence of interest in analogue tape – and specifically professional tapes recorded at 15 IPS. Over the past few years, companies such as The Tape Project in the USA and Fonè and Open Reel Records in Italy are focusing on re-releasing copies of the master tapes of original analogue recordings. Then there are labels like the Swedish Opus 3 Analogue Master Tapes, Open Reel Records of Italy, Yarlung Records of California, Ultra Analogue Recordings of Canada and Chasing The Dragon in the UK, that are now producing superb sounding modern recordings made on analogue open reel tape.

These are not cheap – costs range from around £130 to about £380 per title – but the fact that they’re selling out shows there is real demand. Once you have heard these on a properly serviced open reel tape deck, it is really hard to go back to any other music source. The sound of professional analogue tape is something that few people have heard outside a recording or mastering studio, and it’s quite a thrill. It’s not just the technical side of things – the bandwidth, low noise floor and firecracker dynamics – it is the amazingly natural and unmediated sound that’s hard not to love. That’s why there is a small but steady open reel revival happening in the hi-fi world right now – so it’s a great time to hear for yourself.


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Neville Roberts's avatar

Neville Roberts

A Chartered Scientist, Chartered Engineer, Chartered Physicist and a Fellow of the British Institution of Engineering and Technology, Neville has worked as a Director of the British National Health Service, for the Ministry of Defence and in private industry. He’s a lifelong audio enthusiast and regular contributor to British hi-fi magazines, with a passion for valves and vinyl.

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