The Legendary Deacy Amp

The Deacy Amp is an amplifier created by and named after Queen bassist John Deacon and used by guitarist Brian May.It was created in the early 1970s using a piecemeal amplifier found in a skip by Deacon and a treble booster, constructed by May. Also used was an amplifier circuit board stationed into a Hi-Fi speaker cabinet, powered by a 9-volt battery. The amp was used along with May's Red Special guitar and his treble booster.


History and background of the Legendary Deacy Amp:

'Twas a dark and stormy night when yonder brave struggling musician set foot upon the cobblestones of olde London Town, yet before he had gone half a league our hero was to stumble across a most wonderful sight: a sword miraculously placed in a (skip sorry) ... a stone" ... cough cough... er yes...

Perhaps the origins of this famous piece of "junkyard electronic wizardry" might sound to some as though it could have come from the pages of a "Boy's Own" adventure novel, but as often happens in life, coincidence and felicitous circumstance played their part in bringing into the hands of firstly John Deacon and then Brian May the small amplifier that the Rock Music world has come to know as the "Deacy Amp".


Deacy Amp Origins:

In July 1998 John Deacon related to me the circumstances surrounding his putting together of this unique sounding amplifier and speaker box.

John literally found the circuit board as he was walking down the street one day in London - this occurred in early/mid 1971 at a time when he was first playing in "Queen" with Freddie Mercury, Roger Taylor and Brian May.
Being a keen electronics experimenter (and was then studying for an Electronics Degree), John's attention was drawn to the wires that were dangling over the side of a builder's skip - the large skip was sitting on the side of the road filled with rubbish which was about to be taken away to the tip.

These wires were attached to a circuit board and John's curiosity led him to examine the board to see if he could salvage it and put it to some use. He initially thought that the circuit board might have come from a battery operated cassette player or radio, and after inspecting it decided it would do the job as a small practice amplifier for guitar (John played guitar as well as bass).

John coupled the newly found circuit board with a spare bookshelf speaker box that he had lying around - the circuit board was fixed inside the speaker box with two screws and the finished product featured only the most spartan of controls:

On the back panel of the speaker box was fitted a single jack socket to plug the guitar lead into - the amp's power was turned on by simply connecting the two battery clip leads (which came out from the back panel) to a large PP9 battery - and through most of its history the Deacy Amp has had no volume or tone controls whatsoever although John remembers that initially he rigged up a volume control which hung loose outside the speaker box - soon after he fixed the volume internally on full, having found that this sounded best - there were definitely no deluxe frills with this model!

With a standard guitar plugged in, John said the amp possessed a warm and pleasant (and partly distorted) sound but lacked brilliance or much definition - however a new way of using this little amplifier was about to be found that would change its sound and make it an invaluable part of Queen's recording armoury...

By some chance John brought his practice amplifier along to band rehearsal one day and showed it to Brian - immediately he said, Brian was interested in the amp's possibilities - and especially so when he heard how it behaved once he plugged in his innovative home made Red Special guitar and Treble Booster pedal.

These two changed the amp's sound dramatically, overdriving both the input and output stages and producing a richly distorted but defined and sustained sound which resembled such things as violins, cellos and even vocals.
John commented that the rich saturated compressed type of distortion produced by the combination of Red Special guitar, Treble Booster and Deacy Amp was very unique and different to the more typical harder sounding "sawtooth waveform" distortion common at the time in many guitar effects and amps.

He mentioned that the recording engineers that the band were working with particularly liked the way the amp behaved in the recording studio. Here the amp would produce a constant response, whereas the engineers found it more difficult to capture on tape the exciting and dynamic sound of Brian's Vox AC30 amps.

John's small amplifier became known as the "Deacy Amp", and featured regularly on Queen albums where Brian used it for his creative, highly original "Guitar Orchestration" multi-tracked pieces. These were painstakingly built up line by line (and even note by note on some of the more complex pieces such as "Good Company" from Night at the Opera). Although the Deacy Amp is a deceptively simple looking piece of equipment, the wide number of creative uses that Brian has managed to find for this little piece of rock history is nothing short of remarkable.

On occasions Brian's Vox AC30 was combined on tape with the Deacy Amp but usually on Queen records it was just the Deacy Amp alone used for the multi-tracked guitar orchestrations. Brian has described the way that the Deacy Amp's sounds sit and blend together when recorded as being "symphonic" compared to other amps used for this purpose, whereas when the AC30 was tried its combined sounds didn't have the same character and effect.

The tracks "Procession" and "The Fairy Feller's Master-Stroke" from the album "Queen II" (released in March 1974) saw the first recorded examples on a Queen album of the Deacy Amp.

Perhaps the best known example of the amp's use is "God Save The Queen" from 1975's "A Night At The Opera", whilst possibly the most unusual use was for all of the jazz band sounds on the song "Good Company" (trombones, clarinets and all!), from "A Night At The Opera".

The Legendary Deacy Amp continues to this day in good health and continues to occupy an important place in Brian May's recording studio.


Technical Background of the Deacy Amp

In early 1998 Brian May asked me to take apart, photograph and document all aspects of the Deacy Amp's circuit board, components and speaker box. This work was conducted at Brian's Allerton Hill studio with the valuable assistance of Pete Malandrone during the time that I was restoring Brian's famous Red Special guitar.

In all the time that John and Brian have used the Deacy Amp, interestingly it has never broken down or needed repair - and had consequently never been opened by anyone. As I have mentioned previously in a QFC publication, for me this task definitely felt a little (nervously) like being a guitar version of Indiana Jones examining a priceless dusty relic from antiquity...

After the Deacy Amp was examined in full, Dave Petersen and I then set to work on building for Brian 3 "Deacy Amp replicas" which were finished in August 1998. The aim was for these to serve as backups for Brian should anything ever happen (heaven forbid!) to the original Deacy. These 3 amps achieved approx 85% of the Deacy's elusive special sound - however upon returning to my Australian base I have conducted further Deacy Amp R&D during the last 6 years - edging the sound even closer to the original Deacy - and have built two new models which hopefully one day could possibly serve for some future replica amp design template.

The above work of Dave Petersen and myself in 1998 has also happily led on to the development with Vox of the very handsome white Vox BM1 amplifier.

The BM1 amplifier has been based around the original Deacy circuit as much as possible given that it is an affordably made production amp utilising modern technology - although the Vox BM1 does not use the temperamental and hard to obtain Germanium transistors, it produces a excellent sounding modern version of the original Deacy Amp sound, and offers many flexible, useful features to the guitarist.

When combined with Brian's wonderfully innovative Red Special guitar, the Vox BM1 amp allows a versatile range of rock guitar sounds to be produced, and is an amp suited to both the novice player as well as the most accomplished professional.


Deacy Amp Circuit Overview:

The Deacy Amp circuit is a 1950s audio style Germanium transistor push-pull circuit, utilising in its front end an AC125 and AC126 respectively, with the push-pull Output stage comprising two AC128 Germanium transistors.
It also features a Driver Transformer and an Output Transformer and is similar to several designs of the time, which can be found in the Mullard Reference Manual of Transistor Circuits (see pages 168, 170 and 171).
John Deacon slightly altered the front end of the amp to allow it to better suit guitar frequencies, and it will be amusing to many people to learn that this design had been originally created to run cleanly and undistorted in audio use - a very far cry from the way Brian May turbo-charged the little amp for guitar use!
The speaker box contains a 6.5" 4 ohm twin cone driver speaker and a small tweeter speaker which is no longer working The Deacy Amp is powered by a large 9 volt PP9 battery and its power output is approx one watt.


The first time that I heard Brian May's amazing guitar orchestrations on the albums "Queen II" and "Sheer Heart Attack" I was left in a state of disbelief and awe - it didn't seem possible to me that these incredibly creative layered sounds could be obtained from a guitar!

(Little wonder that several of the first Queen albums proudly proclaimed "No Synthesizers!" on the album cover.)
Over the years the rock music world has become used to the dazzlingly original (and at times unearthly sounding!) sonic textures that Brian has woven like a tapestry using his equally dazzingly original Red Special guitar played through the wonderful piece of "junkyard electronic wizardry" that we fondly know as the Deacy Amp.
How fortuitous it was that John Deacon's curiosity led him to examine the wires and circuit board that was about to have its last journey to reside at the bottom of a garbage dump!

And that further circumstance would bring this fabulous "distortion engine" of a pint sized amp into the hands of a true guitar master who could then use it to weave melody (like no other rock player), symphonic layering, counterpoint - you name it! - into the strikingly original music that he and his fellow band members John Deacon, Roger Taylor and Freddie Mercury would create.


In the very near future Brian May, Jen Tunney and myself will be working on producing a Deacy Amp section for Brian's website - we are really looking forward to this piece and hope that many people will find it both informative and a lot of fun!

Yours sincerely,
Greg Fryer, Fryer Guitars Australia.
22nd June 2005.

PS: I would like to offer my thanks to several people who have lent their assistance for this article: Brian May, John Deacon, Brian Zellis, Pete Malandrone and Dave Petersen.



The recent controversy surrounding claims made by Mr. Pete Cornish about the Deacy Amp:

Mr. Cornish, as many people would know, is a well-known and respected specialist music electronics maker who produced many pieces of equipment for Brian May and Queen during the 1970s and 1980s.

Recently Mr. Cornish posted on his website information about a "recording or practice amplifier" that he had apparently built for Queen Productions in 1976. On the surface of it, this amp appears to bear some similarities to the Deacy Amp - indeed earlier versions of Mr. Cornish's article "The Recording Amplifier" claimed that his amplifier WAS the Deacy Amp.

This claim is completely incorrect and can be shown to be so in several ways - it appears to stem from a simple misunderstanding on Mr. Cornish's part which is due to the similar size, intended purpose and approx time of manufacture of the two amps.

Brian May's long time guitar tech Jobby (also known occasionally by his real name of Brian Zellis!) has recently pointed out another likely reason for this misunderstanding: that Pete Cornish rarely if ever visited Brian and Queen in the recording studio, prefering to remain hard at work back at his workshop, with Jobby and Ratty (Peter Hince) communicating with Mr. Cornish about what was needed for Queen.

This is perfectly understandable due to the fact that Pete Cornish at the time was the leading specialist in UK music electronics, and would have been heavily in demand by many music acts.

In fact Jobby recently mentioned that he never once saw Mr. Cornish at the studios during a Queen recording session - this would appear to confirm the view expressed by other people that Mr. Cornish was not aware at all of the Deacy Amp's existence until the recent release of the Vox BM1 amp in 2003 - other recent email corresponce (kindly provided by Mr. Mark Reynolds) between Mr. Cornish and Mr. Reynolds also corroborates this.
And because the Deacy Amp never broke down or needed repair during that time, then it was consequently never brought into Mr. Cornish's workshop and (amazingly) never to his attention!

(All this despite the fact that Brian May has spoken about the Deacy Amp several times in worldwide guitar magazine interviews since at least 1983...)

Because there has been much correspondence and discussion on the internet about Mr. Cornish's recent website articles it would now seem appropriate to clearly list below the reasons why these assumptions are incorrect - and please bear in mind that this is not meant in any way as being a criticism of Mr. Cornish who many of us hold in high regard - it is simply to clear up this unfortunate misunderstanding.

1. John Deacon's small amplifier first appeared on the album "Queen II" which was released in March 1974 (on the tracks "Procession" and "Fairy Feller's Master-Stroke"). Recording for "Queen II" had begun in August 1973. This predates Mr. Cornish's amp by over 3 years (his amp was invoiced on 14-10-76.)

2. Brian May has recently told me that to the best of his knowledge he has never used any other amplifier than the Deacy Amp for his famous guitar orchestrations on Queen albums. Jobby also confirmed that it was always the Deacy Amp which was used for this work.

3. Brian and Jobby cannot remember ever seeing the amp that Mr. Cornish describes on his website - the photo of Mr. Cornish's amps appears to be of 2 recent amps which feature (according to Mr. Mark Reynolds) a recent version of Mr. Cornish's badge. Photos of the original 1976 amp would at least confirm its existence.

Some people have postulated that the 1976 amp could have been used elsewhere in Queen Productions - perhaps as a practice amplifier whilst touring - or perhaps like Brian's original Rangemaster pedal the amp might have been lost or even stolen - this unfortunately happened to some Queen equipment at times.

4. The RS amp (which incidentally according to Mr. Reynolds was a stock RS kit amp and not of Mr. Cornish's design) appears to be a very different style of amplifier to the Deacy Amp - it is listed on Mr. Cornish's RS invoices as a 3-watt audio amplifier which had an 8ohm speaker. Mr. Mark Reynolds has interestingly confirmed through his business contacts with RS that the kit amp which Mr. Cornish purchased in 1976 was an IC Chip amplifier.

Mr. Cornish invoiced this amp to Queen Productions as a "Practice Amplifier" - only later has the term "Recording Amplifier" been introduced.

5. Several experts in the field have recently confirmed that the sound of Mr. Cornish's amp would be completely different to that of the Deacy Amp when driven into distortion with Brian's Red Special guitar and Treble Booster.
Whereas the Germanium Transistor/Transformer coupled Deacy Amp produces smooth harmonically rich compressed distortion, an IC chip amp of the RS type would produce harder, edgy sounding square wave distortion (and would not have anything like the same compression), and would clip and distort much more suddenly than the Deacy, which slides very smoothly into its rich sweet distortion.


Brian May's extensive use of John Deacon's small amplifier in Queen recordings is well known and documented - obviously because these events occurred several decades ago, we are relying on people's recollection and this means that it is always open to interpretation - this of course is the nature of history.

However we feel that the subject of the Deacy Amp leaves no shadow for any doubt - and based on the information presented above we therefore leave it up to the individual to judge for themselves.
Several people have lent technical and other assistance for the above section - I would like to thank Mark Reynolds, Martin Pitcher, Warren McAlister, Nigel Knight and Brian Zellis for their valuable help.
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