Brian May's "Deacy" transistor amp

Discussion in 'Shock Brother's DIY Amps' started by ArcticWhite, Sep 29, 2021.

  1. ArcticWhite

    ArcticWhite Tele-Afflicted

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    Fascinating, well produced, five minute video on YouTube. It only has about 3000 views but deserves many more.

    This is the little amp that John Deacy, Queen's bassist found in a skip (dumpster) and resurrected as a practice amp. Brian May loved it, and used it regularly in the studio.



    Here's the sound.

     
    Last edited: Sep 29, 2021
  2. Lone_Poor_Boy

    Lone_Poor_Boy Tele-Holic

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    Neat back story.
     
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  3. Greg70

    Greg70 Tele-Holic

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    Interesting story. I've heard of this before. Thanks for sharing!
     
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  4. dougsta

    dougsta Tele-Meister

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    It would help that John Deacon was also awarded a 1st Class Honours Degree in Electronics the same year he joined Queen and designed some modules in addition to the AC30 that gave Brian May his signature sound.

    The guitar tech in this is very Spinal Tap but explains Brians stage setup
     
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  5. mexicanyella

    mexicanyella Friend of Leo's

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    Man, what a killer range of clean to crunch! That rocks! And nicely played and demonstrated too.
     
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  6. Lone_Poor_Boy

    Lone_Poor_Boy Tele-Holic

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    Yeah, that's what I was thinking. Your average Joe Musician would have kept walking.


     
  7. BigDaddyLH

    BigDaddyLH Tele Axpert Ad Free Member

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    I used to love the sound Brian May got, but now that I know it's a SS amp, I hate it :mad::mad::mad:
     
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  8. mountainhick

    mountainhick Tele-Meister

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    Twists the brain duhssinit?
     
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  9. aging_rocker

    aging_rocker Friend of Leo's

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    That's what happens when you listen with your ears and not your eyes...:D
     
  10. NTC

    NTC Tele-Holic

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    Just think about all of those solid state pedals people use to get their tube amps to sound great.
     
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  11. TobyZ28

    TobyZ28 Tele-Meister

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    Look what I'm working on:
    Toby-Deacy0.2.png
    (First ever schematic -> Layout I've ever done.. lol)
     
  12. ArcticWhite

    ArcticWhite Tele-Afflicted

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    I know what you mean!
    But it may make you feel better to remember this little amp uses five unobtainium germanium transistors for amplification, and some extremely esoteric transformers as well.
    Germanium transistors are even more weirdly unpredictable than tubes!
     
  13. ArcticWhite

    ArcticWhite Tele-Afflicted

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    Where are you getting your transistors? I see the ones on Fleabay are coming from Bulgaria mostly.
    Can you post your schematic?
     
  14. thankyouguitar

    thankyouguitar Tele-Meister

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    My inspiration! I have spent many hours over the years hacking together radios and speakers I've found in the garbage into fantastic sustaining beasts because of this story. Excellent videos. Thank you for posting. I will now look into getting this replica....

    edit: looks like I'm about 10 years too late! XD
     
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  15. Chiogtr4x

    Chiogtr4x Doctor of Teleocity Silver Supporter

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    I agree, that's the sound and the touch too! Great playing.

    But I did notice that the guy doing the demo just in passing...

    ( note: and this always seems to be the case when folks are talking about other famous guitar players' signal chains- they glide over something that may be integral to their sound- like Angus Young or Rory Gallagher- it's NOT just guitar >amp...)

    ... says " Brian always used this with a Treble booster, which is what we are doing today.." ( right?)

    This ( IMO) is no trivial bit of information, as doesn't using one of these greatly influence how the amp is going to sound?

    What do things sound like w/o using the Treble booster?
    I've never used one, but aren't they really powerful, and greatly influence sound?
    Just a curiosity
     
  16. mexicanyella

    mexicanyella Friend of Leo's

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    Yeah, I agree; he might have spent at least as much time on the treble booster’s effect on the sound as he did the variable voltage power supply.
     
  17. Fuelish

    Fuelish Tele-Afflicted

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    Pretty amazing, Dr May building a successful career/sound on a home made guitar and, partly, on the dumpster rescue Deacy......
     
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  18. TobyZ28

    TobyZ28 Tele-Meister

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    Here is the best Schematic I've found so far - I'm going to pull the original radio schematic for the Supersonic PR80, compare and adjust as needed: upload_2021-9-30_8-53-58.jpeg

    I literally whipped the layout up yesterday more to just get a feel if its a feasible circuit for me to do. I did some light research on sourcing those Germanium Transistors and have also only seen the Russian equivalent's on eBay as well.

    If I go ahead with the build, my goal is not to replicate Deacy exactly, it's more a fun project to see where I get to keeping things as close to spec as possible but not worrying too much if something is a little out of alignment.

    I'm not too worried about the transformers, but yea getting the right unobtanium transistors seems like it will a bit of an impossibility and may make or break my amp..
     

    Attached Files:

    Last edited: Sep 30, 2021
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  19. ArcticWhite

    ArcticWhite Tele-Afflicted

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    The weakness of the Deacy is that of many small amps - it farts out the bass. The treble booster gets that under control.
    Treble boosters are one of the simplest and earliest pedal circuits, so there's not much more to say about it, other than you need to use one with the Deacy.
     
    Last edited: Sep 30, 2021
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  20. ArcticWhite

    ArcticWhite Tele-Afflicted

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    I agree on all counts.
    I've been thinking about building one out of an old radio, and just using whatever is in there. As long as you're using a germanium based circuit you should get something interesting.
    And I've never been interested in replicating someone else's precise tone anyway!

    Edit: The treble booster seems pretty important however. I'd probably include one in the same box.
     
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