Heathkit AD-27

A 1960s quest to play music in stereo leads to the purchase of a Heathkit hi-fi

“I’d never spend a hundred and thirty quid on a record player,” Gavin scoffed in contempt when I told him what my Heathkit stereo had cost, “especially when I had to make it myself.”

Such derision was painful coming from one of my best friends, but he did have a point. £130 in 1970 was today’s equivalent of around £1,750 in terms of prices, and possibly twice that in terms of earnings, so it was indeed a worrying amount to spend on just “a record player”.

Gavin’s dismissiveness should not have been a surprise. To begin with, he did not seem very musical going by what I’d heard of his hymn singing in school assembly. Secondly, his main interest was animals. If he had managed to save £130 he would have expanded his menagerie of amphibians, reptiles and cage birds. I would have quipped just as quickly that I’d never spend a hundred and thirty quid on a twittering flock of Java sparrows, especially then to have to feed them and clean out the bird mess.

I've always liked music. When my mother did her housework to Housewives’ Choice on the Light Programme in the nineteen fifties, all the songs went straight into my head and stayed there (e.g. almost at random: Mitch Miller’s ‘Yellow Rose of Texas’; The Four Lads’ ‘Standing on the Corner’; Eve Boswell’s ‘Pickin’ a Chicken’; Michael Holliday’s ‘Story of My Life’; Perry Como’s ‘Delaware’;  ... ). And later through the nineteen sixties pop explosion I recorded hours of LPs and singles on my reel-to-reel tape recorder. I learned to play guitar and clarinet, and even began to like classical music.

The attraction was always the music rather than the words. I could never understand the appeal of the tuneless Bob Dylan or the droning Leonard Cohen, and when performers came along who were more concerned with how they looked than how they sounded, they left me cold – I’m thinking here of posers such as David Bowie and Marc Bolan. I belatedly came round to appreciating Bob Dylan’s genius, and even Leonard Cohen’s, but in 1970 I would have always gone for the spectacular musicianship of The Who or Jethro Tull any day.

It therefore seemed entirely justifiable to spend a large sum of money on audio equipment – not a “record player” but ‘hi-fi’ – high fidelity stereo, the high quality reproduction of sound. Something of similar quality would be costly even today, despite the shrinking price of consumer electronics over the intervening decades.

People forget now that when the early Beatles and Rolling Stones records came out they were in single channel mono rather than binaural stereo, played in most homes on simple self-contained Dansette-type record players. Mine was a Philips, but basically the same – it had a built in amplifier with a single loudspeaker, the turntable speed could be adjusted for 33 rpm LPs (later called albums), 45 rpm singles and the old 78 rpm records, and it had a drop-down autochanger which allowed around half a dozen records to be played automatically in succession. The sound quality was not all that great.

My first LPs were all monophonic: ‘The Hits of the Animals’ (an export version bought in Belgium), Georgie Fame’s ‘Sweet Things’ and Gustav Holst’s ‘The Planets’. I didn’t own any others for some years  because I could lend these out in exchange for others to record on tape. LPs began to appear in stereo during the latter half of the nineteen sixties, but as they were downwards compatible most people continued to play them on mono equipment. I first heard true stereo at a friend’s house and was thrilled by the way Jimi Hendrix’s guitar floated ethereally across the room from one speaker to the other.

Shure phono cartridge and stylus, with boxes (these are from later in the 1970s).

When I got the Beatles White Album in 1968 it was in stereo, and I wanted to know what it really sounded like. I bought a Shure stereo phono cartridge – the cartridge is the part that holds the stylus underneath the head of the record player arm – and wired it up so that one stereo channel played internally through the record player as usual, and the other externally through my tape recorder. It worked, but not very well. The aeroplane at the beginning of the first track, ‘Back in the U.S.S.R.’, did just about fly across the room in front of me, but it wasn’t all that convincing. Trials with other bits and bits and pieces of equipment fared no better.* It might have been stereo but it was certainly not high fidelity. After a while I gave up and went back to mono. As my uncle put it, “Good mono is better than bad stereo.” There was nothing for it but to save up for a proper system. It had to wait until after I started work.

Before the nineteen seventies, ‘hi-fi’ was an expensive minority interest and proper systems were expensive. One of the first affordable products was Alan Sugar’s Amstrad 8000 stereo amplifier which cost £17, but Sugar himself now admits that it wasn’t very good – possibly no better than my own first faltering trials. Hi-fi also still came as a collection of separate units – a turntable or record deck, a radio tuner, a tape deck, a pre-amplifier, an amplifier and loudspeakers – interconnected by a confusion of wires hanging behind in a spaghetti-like, dust-collecting tangle. Integrated music centres which came along around 1973 avoided some of this wiring mess, but their sound quality at first still tended to be poor. It was some time before consumers began to look for higher quality.

My Heathkit AD-27 Stereo Compact

Before these things came to market, the most cost-effective way to get high fidelity stereo was as a build-it-yourself kit – a collection  of wooden cabinets, chassis parts, printed circuit boards and electronic components. I bought a Heathkit AD-27 stereo centre comprising a stereo tuner/amplifier (Heathkit AR-14) and integrated record deck (BSR McDonald 500A), together with large Heathkit speaker cabinets containing bass and treble loudspeakers.

It took several weeks to put it together. One problem for me was that there were around a hundred and forty resistors of around sixty different values identified by colour-coded bands: green-blue-brown for 560 Ω (ohms), grey-red-brown for 820 Ω, yellow-violet-orange for 47 kΩ. Now, as previously posted, distinguishing red from brown from orange from green from grey is no simple matter for me, but I managed by sorting them into piles and checking I had the correct numbers of each according to the list of components. It’s a wonder I did it right, but I did.

Extracts from Heathkit AD-27 documentation
See links at end of page to download full manuals from Google docs

For the next few weeks I soldiered on with my soldering iron, mounting resistors, transistors, capacitors, diodes, chokes and other components on to printed circuit boards. I screwed together the metal chassis and wired in the boards, power supply, knobs, switches, sockets and other parts. I sometimes worked on it in the early hours of the morning. One night my dad walked wondering why the light was on, and seeing a stream of smoke rising from the soldering iron said in surprise, “Oh! Are you having a cig son?”

The speakers came flat packed and had to be put together. The back used a surprisingly large number of screws. One of the bass speaker cones had to be sent back and replaced because it rattled.

When at last it was finished it didn’t work. Despite re-soldering all the joints I wasn’t getting anything like the correct voltage readings at specified points on the circuit boards. I sent it back to Heath of Gloucester for attention, and for a nominal charge they quickly fixed it. Whether the problem was my fault is unclear because although they carried out more re-soldering, they also had to replace a faulty component.

On its return, I installed the unit in its wooden cabinet and switched it on, and it worked. My ‘good mono’ uncle rushed round to witness the moment, and as the full orchestra came in and rose to a crescendo near the beginning of the Peer Gynt Suite, without any sign of distortion, he gave me a thumbs up sign and said, simply, “It’s a good ‘un.” And it was. It had a wonderfully rich, warm tone.

It malfunctioned once more when about four years old, and I couldn’t mend it. I sent it back to Gloucester a second time and again they replaced a component and re-heated some of the joints. As well as making wonderful equipment they gave wonderful service.

It gave me years of enjoyment. Even my dad started buying records to listen to on his Thursday half-days off.  I was a bit put out to find Bing Crosby, Vera Lynn and Mrs. Mills among the LPs in my record box.

Despite the expense and derision, the Heathkit was well worth the money. But the fortune Gavin spent on animals was a much better investment. I never became a rock star but he later became a vet.


Here are a couple of YouTube videos of AD-27s, although the first one is in a completely different cabinet and you have to look near the end for a good view of the deck.

* In due course all the bits and pieces of equipment got thrown away: my Philips reel-to-reel tape recorder, an almost identical two track machine acquired for nothing from a friend who no longer used it, my uncle's old Grundig tape recorder, an extension loudspeaker and belatedly the Heathkit around 2003 after spending years in the loft. People are now interested in these things again, and I wish I still had them. I have a photograph from a wet morning in spring, 1978, showing my old record player, an extension loudspeaker and my uncle's old Grundig tape recorder waiting forlornly at the side of the road for their fate with the dustmen.

Links to Assembly Manuals and Related Items on Google Docs

The Heathkit AD-27 was based on the Heathkit AR-14 stereo tuner/amplifier.
Specification Sheet - Heathkit Kit Builders Guide - Invoice and miscellaneous items

AD-27 Assembly Manual (manual number 595-1134 dated 28th March 1969).
The circuit diagram which folds out from page 115 contains very small text so I have scanned it at higher resolution.
Assembly manual - Amendments and additional Information - Circuit Diagram

Berkeley Loudspeakers (model SCM-3, manual number 595-G590-01 dated 10th September 1970).
Assembly manual - Amendments - Additional information