Life with a Brenell


My interest in tape-recorders goes back to the early 1960s when my school friends had 'Fidelity', 'Elizabethan', 'Philips' and 'Ferguson' tape-recorders. Keen to have our own, my brother and I sold our Hornby-Doublo 3-rail trainset (fools!) and with our pocket money bought a splendid 'Marconiphone 4210', 7" 1/4 track mono. On this we recorded Silver City's Bristol Superfreighters and Douglas Dakotas which flew overhead from nearby Ferryfields Airport, or we would sit in front of the TV, microphone in hand, recording "Top of the Pops", daring anyone to breathe and, on Sundays, 'Pick of the Pops' direct off the radio.

While in the sixth form, a brand new language laboratory was installed in the school. Knowing our interest in tape-recording, the Head of Languages (who was also our school's ATC squadron adjutant) volunteered myself and a fellow cadet to load lessons and maintain the equipment. It was built by Cybernetic Developments, to whom we attended a brief course on servicing the indestructible Truvox 100 master deck and the less reliable 36 or so Thorn-based student decks (which for the life of me I cannot now describe). Great fun was had at the weekends recording the week's lessons while listening to The Beatles... for which pleasure we each received 18/- per week!

My brother had converted to cassettes, but I hankered after a Ferrograph Series 7 or a Brenell STB2 with its mesmerising array of knobs - the awesome Revox A77 was well beyond reach. It was not until I had left Polytechnic that my finances allowed me to buy a new Sony TC-377. This was a truly delightful machine which served me well until I got a myself a mint Revox A77 Mk.1. Then, when getting my faithful Armstrong receiver serviced, I fell for a mint Brenell IC-2000 in the engineer's shop window. I had long known of the mysterious IC-2000, but this was the first I had seen one in the flesh. I was smitten; it was love at first sight... and a week later, I was broke!

As Brenell's adverts had promised, the IC-2000 formed "the heart of my hi-fi system" connected as it now was to my Garrard 401, Armstrong 626 and Mordaunt Short Pageants. With the excellent services of Geoff Kremer's ServiceSound, I now began my serious collecting of Brenells and researching their and other companies' histories, M'Lud.

Overview

I don't profess to be either an audio-engineer or electronics expert, so the following comments are from personal experience and observation. First, it must be realised the youngest Brenell is over 35 years old; most Mk.5s are about 50 but fortunately for us, Brenells, pre-Series 7 Ferrographs and Truvox 100/200 series are of substantial build quality and mechanically, bomb-proof.

Most domestic Brenells - the Mk.2, 3-Star, Mk.4 and Mk.5 will have led an easy life (even if long relegated to the attic) while industrial and professional models such as the 10-1/2" STB, Mk.6, Type 19 and Mini-8 are invariably for sale through simply wearing out! However, good ones can still be found and, like most British audio equipment, can be resuscitated by specialists.

When buying any second-hand equipment, it is very much a case of 'caveat emptor' - let the buyer beware. Nothing is sold without good reason, so ask! Most vendors are honest, but there are many rogues who will disguise, or not declare, a fault especially on internet auction sites. If at all a possible, see the machine running for yourself and test it with the vendor. If posted to you, don't be tempted to power it up as soon as you unpack it, for despite the best efforts of the vendor and carrier, they will get 'shaken up' in transit and you will be assured "well it woz working OK, Guvn'r"!

Check for loose wires, valves etc., then wire in series a 100W lamp limiter into the mains supply to avoid 'blowing' a fuse and don't poke around inside with the mains switched on unless you really do know what you are doing! Be aware that the Brenell design allowed many professionals and keen amateurs to modify the deck and pre-amp to suit specific needs. This is not always evident, so get hold of the circuit diagram showing such modifications - it will save a lot of headaches later on! Better still, get a competent audio engineer to check it out for you.

First inspection

It is equally true of any piece of mechanical equipment, be it a vintage camera or Brenell, that oils and greases will oxidise and solidify. They should be regularly used to keep them in fine fettle. Brenell's own heads and BT-H/AEI motors are almost indestructible but it is not uncommon to find Papst motors and Bogen heads have gone 'open circuit' (shorted internally), generally thought to be through poorly applied internal shellac insulation breaking down through dampness - reinforcing the need for regular use to dry the system.

Delicate heads can also be destroyed by over-enthusiastic attention from ohm-meter wielding users checking for continuity - NEVER check a head with an ohm-meter unless you know what you are doing! Bogen heads are now impossible to source new and are increasingly difficult to find second-hand in working order, especially 1/4 and 1/2 track stereo versions. The excellent British-made 'Phi-Magnetronics' and American 'Nortronic' heads are perfect replacements, but Phi heads are no longer in production. Papst capstan motors on Brenells are also prone to hesitancy; often a motor capacitor/suppressor is at fault. Fortunately the Mullard based valve pre-amplifiers are pretty much bomb-proof, and are infinitely repairable.

Few parts are unique to Brenell: exceptions are the brass 1/2" and 1" capstan sleeves (one is usually missing), the flimsy plastic head covers (often discarded by professional users) and the rubber pinch wheel rollers and idler. A mechanically noisy deck (be it Brenell, Truvox of Ferrograph) is often due to dry bearings or a hardened idler wheel; these can be recast, provided you haven't thrown them away! A blessing with Brenells is that, unlike the Ferrograph Series 7, they used a non-degrading synthetic rubber.

Most plastic control knobs are from Bulgin - some sizes of rhomboid shaped knobs were recently made available again from RadioSpares. Prior to the Mk.5 Srs 3, it is necessary to remove the control knobs and deck mask to gain access to the innards. Original knobs can suffer age-related crystallisation or damage through clumsy access to the small internal grub-screw, especially if seized. Use the correct size flat head screwdriver or hex-key - the longer the better - and exert firm but gentle pressure to avoid the driver slipping and cracking the knob. A really stubborn grub-screw can be sometimes be released by a heated screwdriver to partially expand the thread - but it needs great care. Seizure is often through the rounded grub-screw tip being flattened by over-tightening so, once released, dress the tip and switch shaft, and smear some 'Copperease' grease on the thread to ensure easy removal at a later date. DO NOT overtighten the grubs screw as it will cause the knob to break in half. 

Life with a Brenell

Generally regarded as being more agricultural and mechanically inferior to Ferrographs and Revoxes (to a degree, fair comment) Brenells are generally held to have a superior quality of sound reproduction to a Ferrograph and, when correctly set up, are on a par with a Revox A77. So, which model to get?

The mono Mk.5M Series 3 is undoubtedly the best all-rounder for day to day use - stereo heads can of course be fitted, but you will need an external pre-amp for which Brenell offered their valved Tape-Link. For an off-the-shelf stereo, the transistor Mk.6S/IC-2000 are superb, while the mind-bogglingly complex semi-professional valved STB1 or STB2 will give hours of fun, once fully mastered! Alas few STBs survive as they were used professionally and mostly scrapped once worn-out. The Mini-8 still provides musicians with a wonderful entry into multi-track home-studio recording - if you can afford the tape - but it is most important to remember that the Mini-8 employs a massive, external power supply unit - often missing - which powers through a multi-pin connnector and not the 3-pin IEC 'mains socket' on the back of the deck!

A Brenell tape-recorder comprises three separate units: deck, power supply and pre-amplifier. These were available separately, so it is not unusual to find them in non-standard or home-made cabinets: those illustrated on this website are standard, unless otherwise stated.

Apart from the above head and motor issues, there are no other significant problems. The Sound-Master evolved into the Mk.2, which evolved into the Mk.4, Mk 5, Mk.6 and IC-2000. The delightful belt drive, single motor 3-Star is unique in the Brenell range, both mechanically and in its easily broken and difficult to replace plastic parts. The solenoid controlled Type 19 is quiet different to the Mk.7S and Mini-8. The Mini-8 pre-amp boards can be problematic. 

Cleaning and Servicing

Most second-hand machines will be grubby, but a well wrung, warm soapy cloth will clean off most dirt. Ingrained dirt may need aerosol foam cleaners, methylated spirits or iso-propynol - but please note that powerful solvents can destroy screen printed legends on metal, and leathercloth: methylated spirits will quickly desolve traditional gold-sized transfers. You have been warned! Leathercloth trim can be stuck back down with a suitable adhesive while a good quality, cream-furniture polish is ideal for that final sparkle - again be careful of silicone-polishes. Teak finishes should be treated with teak oil.

Most cabinets used high quality 'Cheney' furniture: gilt on early models and nickel plated on later. These generally polish up with a fine toothbrush and metal polish, but most will by now have suffered considerable pitting, or have plating lifting. There is not much one can do about that but new 'Cheney' fittings are now available again from specialist suppliers.

All mechanical movements, whether pivots, bearings or slide action, require lubrication. Only a drop of oil, smear of grease or 'Vaselene' is needed. BT-H motor bearings do need oiling and even self-lubricating 'Oilite' bushes can dry oil over the years, BUT make sure no oils gets onto rubber wheels or onto the tape guides!

Brenell's owner manuals and circuit diagrams are pretty good. They often appear on internet auction sites, so grab them as, from my experience, those supplied on CDs are often illegible. Be aware there were many factory modifications which were not always updated on circuit diagrams. The compilation (offered in good faith) from this web-site includes most known factory issued circuit diagrams and service notes - but the onus remains on the user to double check. There are very few good books on general tape-recorder servicing, but those by H Hellyer and R Hickman can be recommended.

Spooling and brakes

Spool brakes need careful setting up and adjustment for friction to provide back tension and prevent tape spillage on over-run. These are set up so that paying out is smooth and not jerky as the feed spool empties. If the brakes bind, bad 'wow' occurs. Late 10-1/2" models have settings for 'small' (up to 8-1/4") or 'large' (10-1/2") spools; this must be correctly set before use.

Papst spool motors run at frighteningly high speeds! Never run a Brenell without its spool retaining thumb-screws, whether operated vertically or horizontally, or leave a Brenell to fast wind unattended if you value your tapes! A leader tape is strongly recommended. Unlike late Ferrographs, Brenells did not have a variable spooling speed control, so well before you need to stop the tape, turn the fast forward/rewind lever momentarily to the opposite direction to slow down the spools - you won't do any damage or harm the motors - but if you suddenly centre the rewind lever to 'stop', you will almost certainly get over-spill or, worse snapping.

Tapes

Turntables are DIN-centred, but avoid Ferrograph's 'Hub-lock' spools as these tend to jam on the spindles! Early BT-H/AEI models have alloy thumb screw spool retainers while Papst models had 6mm threaded spindles for a tapped bush (6mm Nylon wing nuts are ideal if missing). 10-1/2" models came with a 3-part, wide-flanged adaptor for DIN, AEG and NAB hubs, but if only using NAB hubs, fit the readily available shallow universal NAB cam-lock adaptors for while the head covers on 10-1/2" models are cut-away, the taller NAB cam-locks make loading difficult. Please also note variations in thickness between alloy and plastic spool flanges requiring shims (provided with the Brenell kit) or adjustment of the output tape guide to protect the tape's edge from damage - this is especially important with 1/4 track recordings.

Alloy 10-1/2" spools are built up around a plastic pancake-hub - most are horribly out of true and may need rebuilding especially as on 10-1/2" Brenells, there is danger of two eccentric spools 'kissing' at high speed and emitting colourful static discharges!

Early Brenells were supplied as standard with a spool of EMItape, but Brenell turned to BASF with the Mk.5 simply because BASF offered a free tape and take up spool for each machine sold! Brenells were duly set up with a bias for BASF LGS, their LP35LH (which remains the author's preference). The Mini-8 however was set up for Scotch tape to better appeal to the American market.

Long Play or Standard play tape? Either - but with the very high spooling speeds and harsh braking, avoid Double and especially Triple Play (which is also more susceptible to print-through). Do NOT use matt-back carbon coated tapes on pressure-pad tape-recorders - ie: Mk.2 to Mk.6 - as excessive friction causes poor wow, while tape stretch may occur on DP/TP tapes. Matt-back coated tape is only suited to the parabolic tape on the IC-2000, Type 19 and Mini-8. Note also that many 'studio' tapes require bias adjustment.

'Sticky-shed syndrome'

Be very wary of tapes liable to, or suffering from, 'sticky-shed syndrome'. This recent phenomenon is particularly evident in mid-1970s to late-1980s tape, mostly matt-back coated. It is primarily through the adoption of the then advanced polyurethane based binders which very gradually absorbed moisture over time, transforming the magnetic oxide into a sticky deposit on guides and heads (many idlers and pinch-rollers suffered the same fate). The first signs are a tendency for the tape not to freely leave the feed spool; for tapes to squeal, show poor wow and flutter and have sound drop-outs as the oxide builds up on the heads. Do not mistake this with the natural oxide build-up through erosion of very old tapes, or high density oxide coatings on mastering tapes.

Note also that not all tapes suffer. Much depends on how they have been stored: they should be always stored in a cool but dry room. Nearly all pre-1970 tapes are fine, especially PVC based. Post 1970s polyester/polyethylene based are susceptible, but varies considerably both between and within brands. The worst are Ampex/Scotch professional tapes yet Welsh-made Scotch tapes appear to be fine, as do most Japanese and BASF/Agfa. However BASF's later LP35FE and some later Emtec (BASF/Agfa) studio tape is now showing signs. Valuable recordings can be recovered by low-bake curing, but such recovered tapes are best discarded once the recording has been transferred.

Microphones

Brenell initially supplied the small high impedence Acos crystal or Lustraphone LD61 button mushroom with their domestic models, but soon began to offer the superior LFV59Z dynamic or VR64Z ribbon as well as Reslo models to customer choice. Transistor models (ST200/400, Mk.6, IC2000, Mini-8) used low impedence.

Wots it wurf mister?

I am often asked what a Brenell is worth. I can only give a rough 'guestimate' based on current e-Bay trends. The only honest valuation is "it's what somone is prepared to pay!"... Make sure it is complete and that heads and motors work. Then set a limit at which you are comfortable and don't get carried away in a bidding-war! Yes, there are some very rare Brenells - but unlike one-off prototypes, as most Brenells were made in batches of 50, the chances are that, like buses, having waited ages, another, better one will come along soon... but why take the chance? It's your decision. If the other-half objects, consider grounds for divorce under unreasonable behaviour!

WOODWORM

This subject routinely appears on internet forums, but there is a truly awful lot of rubbish and 'pet remedies' about woodworm that soon becomes 'fact' simply because some 'expert' googled it on the internet or Wikipedia! My alter-ego is one of many years in 'timber' (woodland, saw-milling, furniture making...), one never stops learning about wood!

It is inevitable that at some point a collector will encounter 'woodworm' in their prized vintage audio cabinet, especially one made from birch-plywood such as a Brenell, bought second-hand. But even if bought new, and lovingly cherished, there is still a small risk of a woodworm attack in one's own sterile home. Why?

Woodworm first becomes evident from fresh piles of gritty dust (frass) and empty 1 - 1.5mm (1/16") diameter flight holes which begin to appear in the spring. Wood (and the animal based gelatine 'Scotch' wood-glues used into the 1970s) contain cellulose, sugars and proteins by which trees grow and on which 'woodworm' feed until they are ready to emerge after a year or two around spring and fly off as a 8mm (5/16") long furniture beetle anobium punctuatum, to mate and lay their eggs - such is their natural life cycle.

Unfortunately, such attacks are random. I can almost guarantee that if two pieces of freshly sawn timber are seasoned side by side, the best will be attacked, and the other not! That's nature - so get used to it! You won't stop then but you can reduce the risk so, when buying a second-hand item, especially one 'kept in the garden shed', put it into a polythene bag and isolate it in a dry room for a year by when woodworm, if present, may (or may not!) become apparent.

So where do we begin?

Freshly felled and sawn 'green' timber is saturated with sugary sap trapped in its cellulose cells and its sap carrying vessels which allows the tree to grow... and insect grubs of all types to have a jolly good feast! As the timber seasons, the watery sap evaporates and the trees 'moisture content' drops to around 23% if air-dried, and down to 10% if artificially kiln dried for the modern centrally heated home. These 'dry' levels are sufficient to prevent most further boring insect attacks... except by the furniture beetle grubs which will merrily chomp through the driest of timbers - even 100 year old antique furniture - because the edible sugars remain, especially in birch much favoured for furniture carcasses and furniture-grade plywood which uses animal gelatine based Scotch glue - the icing on the cake for anobium punctuatum!

The greatest risk of 'attack' comes from dampness so, clearly, storing a wooden cabinet in a damp garden shed makes it far more liable to attack. The wise furniture beetle lays her 3-4mm (1/8") long eggs in a crack or crevice (so they don't roll away) by a source of edible food: the haute cusine is Scotch glued wooden joints stuffed in its corners with nutritious beeswax polish! The eggs can remain dormant for some years, but when they hatch the grubs will eat their way into the wood or plywood leaving any visible trace for a year or two - possibly up to five - before heading for the surface around spring (how do they know?) to fly off and mate. A thump with a rubber mallet at this point will dislodge copious amounts of dust indicating the extent of the hidden damage within - it will be extensive.

Once flown, they have gone, vamoosed, rarely to return. A further infestation will be by pure chance, so prevention is easier then a cure - which always comes too late!

The only truly effective prevention is the precautionary use of pressure treated timber (fully penetrating all cells) using volatile organic solvents carrying effective insecticides and fungicides - but because they work, they are banned by the EU... because they are toxic - or in the creosote, they don't know what's in it! Even so, treated timber is rarely used by furniture makers except when specified by clients where the risk of attack is certain, such as exterior joinery.

It is entirely possible and feasible to fully immerse a finished cabinet in a preservative for a week or two to maximise natural penetration but, as Paul Daniels would have said, that penetration is 'not a lot'! More importantly, it would have to be a (largely banned) volatile organic solvent 'white spirit' vehicle which evaporates, and not a water-based vehicle which will expand the cells and permanently distort the timber as well as lifting veneers!

The only practical prevention then is to keep furniture well dusted and free of eggs and 'food' in a dry, well aired room... and pray!

The science!

Whereas a telegraph pole, pressure-treated with a 'natural' coal-tar creosote distillate will last 100 years, modern man-made 'safe' treatments are barely lasting 20-25 years (little more than the timber's natural durability), while some are already being withdrawn due to their toxicity: Progress! But even timber pressure treated with creosote - the King of all known preservatives or copper chrome arsenate salts (both now banned by the EU) - can suffer attacks, but these are soon stopped. Incredibly, woodpeckers love digging 12" deep holes for nests in creosoted telegraph poles - they suffer little ill-effect. The observant will notice that telegraph poles (garden sheds, fences, boats...) don't rot above ground and rarely deep below ground. However, ALL timbers decay at the ever-changing wet/dry environment 6" above or below ground/water contact level. The rate of decay depends on specie and thoroughness of pretreatment so it is truly pointless spending œ20 treating a naturally durable larch garden fence panel while the fence post on which it hangs has barely seen a lick of treatment at the crucial ground contact area. Indeed, most 'treated' fence posts have received little more than a superficial wipe! There is a world of difference in penetration between vacuum (and superior pressure treatment) over brush-painted!.

Insecticides and fungicides:

By its very definition every man-made insecticide and fungicide is toxic - it kills - so is 'harmful' to the environment: the most effective get banned. The most damaging of all to the environment is 'man' (and woman!) but no politician has the courage to stop us breeding, or spraying us with a homicide to control us!

Pressure treatment forces under pressure preservatives into the inner cells hidden deep beneath the surface (vacuum relies on less powerful vacuum) whereas treatment by wiping, spraying or painting serves little real purpose as it barely penetrates the first cell walls. Liquid treatments only ever travel along the sap carrying vessels by capillary action until resisted by air pressure! Treatments rarely penetrate sideways across the width of the timber except by the rays in certain species, or by osmosis through the cell walls during a long period of steeping. The drier the timber, the less the capillary action! But while steeping end-grain timber in preservative will absorb between 1/16" to 1" depending on specie (oak heartwood is impossible to treat), painting the surface is literally only 'skin deep'.

Now what?

Around spring you will begin to notice the first tell-tale pyramids of dust (frass) and new 'flight holes'. That is the only time that treating a flight hole serves any purpose, but while you won't kill the grub that has already flown, there is a good chance that you will be able to pour enough insecticide into the hole to be absorbed along the dust plugs of other nearby grubs, or be eaten by an approaching grub. It is pure luck as one has absolutely no way of knowing where the grubs are! Keep applying even after the dust stops for it is during the summer that the furniture beetle lays her eggs in corners and cracks! Keep an eye out next spring, for there may well still be active grubs or dormant eggs - ready to emerge!

And therein lies the insurmountable problem; just like hornets, wasps, mice and grey squirrels, furniture beetles attack any time, anyplace, anywhere. Nature happens!

The myths!

Since time immemorial these have been are all manner of mythical preventives from spinknard (Egyptian), whale oil (because whales don't get attacked by sea-worms) to paraffin to God knows what! Most pet remedies 'work' simply because the chance of a repeat attack is so very small - just as is winning a lottery!

There are naturally toxic insecticides found in pure turpentine and the pyrethrum family of flowers (chrysanthemums) used as insect dusting powder, now commercially produced as permethrin while others may contain napthas and phenols... but such is the knee-jerk reaction of politicians that it is difficult to keep up with what the EU has banned - certainly the most effective of the volatile solvent based insecticides and water-borne CCA salts - have been replaced by specie specific insecticides of questionable strength and longevity! While waterborne CCA salts 'fix' permanently on drying, Boron doesn't!

At the end of the day, insects/grubs are killed by physical contact, a predator insect or bird, or chemical insecticides - usually a nerve agent which acts on contact either through pretreatment or by the observant armed with an aerosol. Some people swear by deep-freezing at -18oC but bear in mind that while some live grubs may be frozen to death, many and especially eggs, won't - witness how every summer the Siberian tundra and permafrost temporarily thaws and comes alive with insects and grasses, while one of the most thermally efficient materials is wood... so the surface may be -18oC but the grubs may be as snug as a bug in their (wood-insulated) 'rug'!! Nature is quite remarkable - and always wins!

Repairs

If solid wood has been attacked it is generally acceptable to stop-up the holes and repolish. It'll never look right, so it may be more sensible to cut out the damage and let in a new piece of matching wood/veneer. Unfortunately with birch plywood, in which much of the glue has been eaten (rendering the surviving ply unusable), it is often best to replace the entire panel; that's the easy bit ... but Matching the veneer is the most difficult: indeed, you may never find a close match! Good luck!