Tape Recorders

Two Reel-to-reel machines from the classic era, on the left the Revox G36
and on the right the Ferrograph 632. Both still sound very good, but despite
the reputation of the Revox I think the 632 just has the edge in sound quality.

Tape recorders were introduced into the UK in the late forties, two of the first companies in the field were Wright and Weare (Ferrograph) and Scophony-Baird. Baird did not stay in the market long, but by the 1960's the Ferrograph was the premier British semi-professional machine. Competition came principally from the home grown Brenell and Truvox, and the Swiss Revox. The middle and low end of the market was served initially in the late 50's/early 60's by many other small companies building electronics around bought in mechanics. Gradually these were swept away by machines imported from the continent, especially those from Grundig and Philips.

The home constructor could build his own machine based around mechanics from Wearite, Truvox, Brenell, Motek, Lane, BSR, Collaro or Garrard amongst others. The latter 3 were the big gramophone turntable manufacturers and it was natural that they should turn their attention to this new field. Although Garrard were probably the leading turntable manufacturer their tape deck was a strange design using 4" spools contained in a cartridge, not many machines used this deck. BSR concentrated on the cheap end of the market for many years with their TD1/2 Monarch Deck series. These offered 5 3/4" spool capacity and 3.75 IPS tape speed only and were used by many manufacturers as the basis for low end machines. Collaro produced the most interesting tapes decks of the three and a couple of examples are pictured below.

Philips introduced the compact cassette in 1963 initially aimed at the dictation market. It's ease of use, portability and low cost meant that by 1967 Cassette machines were outselling reel-to-reels (R2R's). Another advantage of the cassette format was its guaranteed compatibility - any tape will play on any machine (although the C120 could be problematic). By contrast R2Rs were originally full track, recording across the full width of the tape. Then half track allowing two separate mono recordings on each side of a tape, or one single stereo recording. Finally quarter track recording gave four separate mono recordings on a tape, or two seperate stereo recordings. A 1/2 track machine cannot play back a fully recorded 1/4 track tape, a 1/4 track machine can play a half track tape, but output will be down. If a half track stereo tape is played on a 1/4 track machine output from one track is lower than the other due to the differing guard area between the recorded tracks. Add to this this different tape speeds used on domestic equipment 15, 7.5, 3.75, 1.875 and 15/16 Inches Per Second. The differing spool capabilities: mains machines normally have a maximum spool size of 5.75", 7" or 10.5". And finally the varying equalisation standards such as NAB and IEC (which was changed over time anyway). This means that any enthusiast needs several machines to correctly play back the tapes likely to come his or her way.

The machines on this page all come from the classic R2R era. I first became interested in them when I bought a Cossor CR1601 (actually a Philips in disguise) from an ad in the local paper. Other machines followed and I ended up with a library of tapes. Unfortunately R2Rs often do not age well, some mechanisms are heavily dependent on rubber drive belts and idlers and after 30 years many disintegrate rendering the machines useless.

Most belts etc are found in the cheap and middle market recorders where one motor was used to drive the tape capstan and the spools via a series of pulleys. The semi-professional machines used a 3 motor system where a motor was dedicated to each function and much less rubber was required. Now that belts etc are unobtainable an enthusiast needing to play/record tapes should seek out a 3 motor machine. My answer to these problems was to build an entirely new machine based around a 3 motor Brenell deck.

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My Homemade Brenell (1/4 track stereo, 3 heads, 3 speed).

The deck started life on a mark 5 type M machine from about 1965. It is fitted with new heads and solid state electronics designed by myself. This was a mammoth project taking about a year to completion. I wanted a machine that would do my old tapes justice and also record to the highest standard I could achieve. The machine is 1/4 track stereo and produces the best recordings at 3.75IPS that I have ever heard. It is a full function 3 head machine with separate record and play amplifiers, facilities include: mono/stereo rec/playback with off-tape monitoring, mixing, echo, track-to-track dubbing, built in 15W per channel monitoring amps with bass & treble controls, front panel bias adjust and headphone socket.

The electronics use a mixture of op-amp and discrete transistor circuits. The constant current for the record head is provided by a valve-style series resistor to swamp the head impedance. To drive this effectively the record amp operates from regulated +/-30V rails. This system gave good sound quality without feedback complications. The erase/bias oscillator is based on Push-Pull FETs. The supply to the oscillator is decayed slowly to prevent head magnetisation when switching off record. The playback pre-amp is op-amp based using shunt equalisation. No signal voltages are bussed around the deck, all EQ switching is DC controlled using analogue switch ICs and relays. Record/play is equalised to the late 60's IEC standard to match my existing library.

The deck has been re-built and modified to be three speed only (7.5, 3.75 & 1.875 IPS) with automatic equalisation selection. The deck has induction motors on the spools and a Papst outer rotor synchronous type for the capstan. The green finish is, in my opinion, the best looking that Brenell offered. The deck, in common with other semi-pro machines of the period, will accomodate 8.25" spools, but today these are a rarity. A version was also produced that could use 10.5" NAB spools (the MK510), no-one I know has ever actually seen one of these.

Brenell were a small company and presumably motors etc fitted to their decks changed over time depending on what was available. Their building in London is today a solicitors office. The company itself was absorbed into Allen & Heath (professional studio mixing desk manufacturers), in about 1980. The last Brenell machines manufactured were multitrack units aimed at recording studios.

Click here to visit my Brenell Zone for more information on these machines

Brenell gold finish deck (1/2 track mono, 2 heads, 4 speed).
This is an earlier Brenell deck from the late 50's pictured in its original packing box! Over the years the external finish used by Brenell changed from gold to green then finally to grey. This deck is fitted with 2 heads and came with the matching Brenell amplifier. 3 induction motors are fitted. The basic design of the Brenell deck didn't change much over the years, but improved motors were fitted to the later versions.

Status: Unknown, awaiting restoration.

Click here to visit my Brenell Zone for more information on these machines

Brenell Mark 5 type M, green finish (1964, 1/2 track mono, 3 heads, 4 speed).

This machine is of the same type that I used as the donor for the deck on my homemade machine. Curiously although this was the most expensive Brenell machine bar the stereo STB model it seems to crop up much more frequently than its cheaper siblings. The cheaper machines used 2 heads and either magic eye or VU metering. Perhaps in this quality end of the market people preferred to pay more and have off-tape monitoring. This machine does actually still have its low speed capstan sleeve, it has been stored by a previous owner on the post just above the counter and tape guide.

Status: Working (just - full of Hunts capacitors)

Click here to visit my Brenell Zone for more information on these machines

Brenell Mark 5 type M, grey finish (1967, 1/2 track mono, 3 heads, 4 speed).
This series 5 type machine is finished in grey and dates from the late 60's. The deck is fitted with three outer rotor type motors.
The upper head cover is missing. These machines sound pretty good at 7.5 and (especially) 15IPS. Operational annoyances include no A/B monitor switch and the seperate equalisation control (necessary because the 4 speeds are obtained in 2 ranges of 3); two different diameter capstan sleeves are used to select either 15/7.5/3.75 or 7.5/3.75/1.875. When these decks come up on the secondhand market the smaller diameter capstan for the lower range is often missing.

Status: Working
Restoration Problems: none

Click here to visit my Brenell Zone for more information on these machines

Collaro Tape Transcriptor MkII (1958?, 1/2 track mono, 4 heads, 3 speed)

Collaro's first attempt at a tape deck, 3 speed namely 15, 7.5 and 3.75IPS. An interesting design because it is bi-directional, eg at the end of a side there is no need to reverse the spools. This is a quite a good convenience feature, Simon and Truvox also produced decks of this type. By the early sixties this feature was being droped and auto reverse didn't really return to R2R's until some of the big Japanese decks of the 70's. The MKIII and later designs replaced the crude arm-riding-on-the-tape driven position indicator with a conventional counter.

I also have a matching Mullard design Record/play amp to go with this deck.

Status: Unknown, awaiting restoration.

Ferrograph 4 (1962, Half track mono, 2 heads 2 speeds)

This machine is in remarkably good condition and must have seen very light use. The deck is the earlier two speed pattern (7.5 & 3.75ips) and has a pause control which just lifts the pinch wheel. It is activated by the chrome button on the right underneath of the head cover.

The knob on the right is in fact an octal plug which covers the auxilliary socket that ca be used to power tuners etc from the recorders power supply.

The series 4 deck does lift the tape from the heads during fast wind and, the tape end detector is part of the erase head assembly which seems much more sensible than the later models swinging arm by the takeup spool. The Ferrograph 2 head machines were fitted with a dummy head in the 3rd position which could be later exchanged for a stereo playback head. The signals are ready connected to the back panel for external amplification.

Sound quality is not bad from this machine, but probably not as good as the series 6 below.

Status: Working

Ferrograph 632 (1966, half track stereo, 3 heads, 3 speed)
This machine is from series 6, the last made using the Wearite deck before it was replaced in 1968 with a new design for the transistorised series 7 machines. It is also the last valve series they made, although a small transistorised monitor amp is also fitted to drive the built in loud speaker. The machine is fully stereophonic with 3 heads allowing for off-tape monitoring. The azimuth of the playback head can be adjusted on-the-fly to get the best results from any tape. Sound quality from this machine is very good at 7.5IPS, but not so hot at the lower speeds.

The case is unusual with the teak end cheeks giving a more domestic appearance than the normal Ferrograph rexine covered box.  Also unusual for Ferrograph is the amplifier: unlike the mono machines which use EF86 pentode-based circuitry, the stereo 6, and the earlier 4, use triodes throughout. This would improve the noise performance and HiFi types would say it gives better sound. The rival F&G 36 series from Revox also used triodes throughout.

Operationally the deck has several quirks which take some getting used to. My biggest gripe is that the tape is not lifted from the heads during fast wind, leading to loud screeches if one does not remember to turn the volume down quick enough. The single control is also rather inconvenient compared to the Brenell or the push-button Revox. Solidly made, these machines are a common sight at rallies and a good buy if the heads are OK. Later models such as this are 3 speed with pause control, the earlier models are 2 speed only.

Brenell decks will clamp any standard spool in place using knurled screws, the Wearite based Ferrographs by contrast, need a special hub-lock spool for best results. Without spool clamping the spools are inclined to buzz loudly during fast wind, fortunately the Ferrograph suffers less. Like the Brenell the Wearite deck will take spools up to 8.25".

Status: Working
Restoration Problems: Equalisation pots had been twiddled, new play head pressure pad required, capstan motor bearings, monitor amp bias pot.

Wearite Deck Brochure from 1966:

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Revox F36 (1963, 1/2 track stereo, 3 head, 2 speed).
Revox's 36 series were perhaps the best family of quality R2Rs of the sixties. The F36 has magic eye record level meters and was built to take the nowadays very rare 10" cine hub spools.

Status: Working

Revox G36 (1966, 1/2 track stereo, 3 head, 2 speed).

Successor to the F36, the later G36 is finished in grey, has moving coil VU meters and can use the standard 10.5" NAB spools. This example is the most common 7.5/3.75 IPS half track model. A high speed 15/7.5 IPS version was also available, but is much rarer. This recorder has the reputation of being the best sounding machine from the classic R2R era. It is certainly good, but so is the Ferrograph 632. Operationally however the Revox is by far the superior machine offering push button control, limited remote control and the possibility of unattended timer recording.

The 36 series are one of the few domestic machines of the classic era not to use head pressure pads. This should have a benificial effect on head and tape life, but does mean that tape dropouts seem more frequent than on a comparable machine using pads.

Due to the lack of any tape slack absorbers the machine does not handle NAB reels as well as the later A77/B77. Revox went through 3 versions of the end-of-tape switch / motor control circuitry. This particular example is a MKII with mechanical switch and extra power supplied to the spooling motors when the tape starts.

Status: Working

Truvox R44/Collaro Magnavox 636 (1966, 1/4 track mono, 2 heads, 3 speed).
Although Truvox were best known for their 3 motor deck semi-pro machines they also competed intermittantly in the middle market. Costs were saved by using decks sourced from outside companies; in this case from Collaro. This is an early all- transistor machine, there were obviously problems however since since the bias oscillator had been heavily modified apparently soon after the machine was built.

When I obtained this machine the Germanium based amplifier was not working properly and in the end I used the deck to build a playback only machine using circuits from 'Practical Electronics'. These circuits were noisy and when the rubber drive on the motor shaft failed I decided to look around for a decent 3 motor deck to try my own ideas out on.

The deck is a bit of a mystery because Collaro went bust in the middle sixties, but this deck was in use until the end of the R2R era. I have even seen it reffered to in print as a BSR deck, certainly the QA sticker looks the same as that under a BSR record deck. Magnavox are the American consumer electronics brand of Philips so the name is also a mystery. This deck was also used by other manufacturers such as Wyndsor and Elizabethan. It appears that Collaro were bought by Magnavox sometime in the sixties and the British operation was shut down in 1969.

Status: Dead

Philips N4407/Pye9137 (1968, 1/4 track stereo, 2 heads, 3 speeds)

As can be seen from the photos these 2 machines are, in fact, identical. The Pye was bought from a car boot sale originally with the idea of maybe using the deck as a basis for a homebrew machine. When I tried it as is with modern tape (and appropriate bias adjustment) the results were so good that for several years I just used it. The DIN spec line input was over sensitive for modern equipment so I removed one stage of the amplifier and all was well.

During the sixties Philips R2R machines, and some radios, were also sold under the Cossor and Stellar brand names with slight cosmetic modifications. This Pye is perhaps the last example of this practise.

The Philips was purchased a few years later for spares, but unfortunately the main rubber drive belt had gone spongy. The Pye has now gone the same. Although Philips machines are one of the most common brands they now need to be treated with caution as their rubber components are simply not stable. I would be interested to hear from any chemists who know what is going on.

These machines were probably also amongst the first domestic types that could be run vertically, which personally I find more convenient.

Status: Dead.

Follow this link to see how Seppo fixed his machine: http://www.geocities.com/kodillak/dux.html

Uher 4200 Report IC (1970's , 1/2 track stereo, 2 heads, 4 speeds)

The 4200 is a member of the most successful family of battery powered portable reel-to-reel recorders ever made - the Uher 4000 series. The first models appeared in the early 60's and these machines were standard equipment for radios reporters everywhere until the arrival of DAT and Minidisc. The mono models are very common on the secondhand market, but the stereo versions are rarer.

The 4200 and its 4400 1/4 track cousin feature a sprung tape idler on the left hand side which is part of a constant tension system. The idler is mounted on a sprung swinging arm which applies a band brake to the feed spool hub. As tape is drawn off the spool by the capstan the resulting tension of the tape causes the brake to release slightly allowing the spool to rotate. Such a system will give pretty constant back tension irrespective of how full the feed spool is. Unfortuanetly the feed spool hub has been constructed in a similar manner to the Bell & Howell worm gear - plastic moulded around metal, and like the worm gear the hub cracks and deforms. This causes the band brake system to feed erratically leading to dropout. On this machine I managed to carefully slit the metal ring with a hacksaw where the plastic had cracked. This meant that the cracks in the plastic hub could then be glued back.

The tape still tended to wander up and down the face of the head and this was cured by carefully adjusting the height of all the guides until the tape flowed smoothly with no sign of wander.

Status: Working
Restoration Problems: Cracked hub, poor tape/head alignment.

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