DEMO ‘Deacy’ Brian May Ge PNP transistor amp [tagboard]

[owlexifry]

originally built this back in jan2022.
i decided to do a lil demo for it last night - but this time with an SM57/focusrite (instead of built-in iphone mic).

the inspiration behind the build comes from the amp known as Brian May’s ‘Deacy’ amp - a germanium transistor amp that Queen bass player John Deacon made out of an old 60s portable radio, installed inside of a bookshelf speaker. turns out Brian May quite liked the tone and actually used it in the studio, usually with a treble booster.

the schematic and project idea comes from Paul Stevenston’s blogspot:

Brian May Deacy Amplifier Stripboard Veroboard Layout

Electronics Projects For Hobbyists Makers And Hackers With Stripboard Layouts

paulinthelab.blogspot.com

there’s already a vero layout available in the blog post above, but i wanted to do it as a tagboard build. so i drafted a layout, ordered some PNPs, and built the circuit. picked up a cheap set of bookshelf speakers, and hooked one up.





it’s certainly not like plugging in to any normal kind of amp. it has no gain or volume control.
all the tone and gain control comes from the guitar.
goes from clean to full on fuzz.

in this recent demo it is running off an old battery that measured 7.9V (guitar straight in, recorded with SM57)

here’s another older demo, different style (guitar straight in, recorded with built-in mic), also old battery.

this is completely out of my wheelhouse and i don’t really have much need or use for it, but it was a fun build to dive in for.

 

[Bricksnbeatles]

Awesome! I’ve wanted to build one of these for years, but always sorta forgot to look into it. After seeing this I’m inspired to do it.

Did you swap out the LT700 for something else? The LT44 is easy enough to come by, but the LT700 despite being very inexpensive is pretty hard to come by from a reputable source it seems.

 

[owlexifry]

Awesome! I’ve wanted to build one of these for years, but always sorta forgot to look into it. After seeing this I’m inspired to do it.

Did you swap out the LT700 for something else? The LT44 is easy enough to come by, but the LT700 despite being very inexpensive is pretty hard to come by from a reputable source it seems.

nah i managed to find both easy enough, got both LT700 and LT44 from an ebay seller (UK). seemed legit enough (sellers inventory was full of amateur radio hobbyist parts etc.)
on a quick search looks like there’s still a couple (also UK based) sellers offering them.

 

[mkstewartesq]

Oh man, this is pure awesomeness!

Like you, I’m a big fan of Brian and have been chasing his tone forever (built pretty much every treble booster there is, own a Red Special) and I did several of my pedal builds around a Queen theme. (I’ve been trying to get up the nerve to request PedalPCB do a trace of the Nick James' pedal version of the Foxx Foot Phaser but I didn’t think others here would be very interested in it since Brian is really the only notable player I can think of who used it).

But I’ve never seen a tagboard build for the Deacy! Thanks so much for sharing this.

As far as the Deacy-yes, its sound is not for everyone and it’s not a “main amp in the rig” kind of amp. It’s really better as a recording amp with a good strong treble booster driving it. But that sound is all over the Queen/Brian work, and not just the orchestral layered parts. Many of the solos hat you might think were an AC30 were actually done on the Deacy.

Super cool project! Terrific work

Mike

 

[owlexifry]

Oh man, this is pure awesomeness!

Like you, I’m a big fan of Brian and have been chasing his tone forever (built pretty much every treble booster there is, own a Red Special) and I did several of my pedal builds around a Queen theme. (I’ve been trying to get up the nerve to request PedalPCB do a trace of the Nick James' pedal version of the Foxx Foot Phaser but I didn’t think others here would be very interested in it since Brian is really the only notable player I can think of who used it).

But I’ve never seen a tagboard build for the Deacy! Thanks so much for sharing this.

As far as the Deacy-yes, its sound is not for everyone and it’s not a “main amp in the rig” kind of amp. It’s really better as a recording amp with a good strong treble booster driving it. But that sound is all over the Queen/Brian work, and not just the orchestral layered parts. Many of the solos hat you might think were an AC30 were actually done on the Deacy.

Super cool project! Terrific work

Mike

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dude… your BM builds are excellent. man i wish i could do artwork like that. that red special looks fantastic.

i wouldn’t say i’m really that much of BM fan, although i can truly appreciate how much of an incredible player and composer he is. his tones are so distinct and forged in my earliest memories of what rock and roll guitar sounds like (because even my relatively conservative lutheran parents would crank Queen in the car when i was a small lad) and then learning about the technical foundations of his tones is certainly fun to dive into.
unfortunately i just can’t play anything that sounds remotely like what BM does.

i’m sure this amp could sound a lot lot better in the hands of a blues enthusiast, or perhaps @MichaelW

 

[Gordo]

That demo sounded nothing like Brian May and was the best part of it. I love this. Really serious potential here.

 

[owlexifry]

That demo sounded nothing like Brian May and was the best part of it. I love this. Really serious potential here.

ayy cheers

wouldn’t mind seeing how it goes with the other bookshelf speaker in series for a little more output…
(pretty sure the output transformer should be able to handle 8 or 16 ohm speaker loads if it’s intended for 4 ohm? - technical data rates a 3.2ohm impedance for the secondaries)

would also like to hook it up to a real guitar speaker (eg. 1x12 greenback) just gotta solder in an output jack

 

[angelrulax]

It would be great to have a Foxx foot phaser pcb available.

 

[Erik S]

It would be great to have a Foxx foot phaser pcb available.

Yeah, @mkstewartesq - I just took a look at the ppcb site: 479 dirt box projects available and approx 5 phasers. I think there’s room for one more.

 

[Feral Feline]

Sweet @owlexifry !

I've wanted to build a Deacy ever since I first read in the late-'70s/early '80s about BM's use of it.
I'm always drawn moth-to-flame for the unusual and esoteric, and here you've done it. Hope to follow in your footsteps in the not-to-distant future.

~~~~~~~~~~~~~~~~~

@mkstewartesq You might be pleasantly surprised, and you'll never know if you don't put it in the Wish List.

 

[mkstewartesq]

@mkstewartesq You might be pleasantly surprised, and you'll never know if you don't put it in the Wish List.

Done!

M

 

[Feral Feline]

Done!

M

What!!!!????!!!!

NO LINK HERE?!