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Thursday, 28 June 2012

Brian May Deacy Amplifier Stripboard Veroboard Layout

Although I am mostly into 90's SkatePunk I am a massive fan of Queen and Brian May, when I was young I obsessed over having the guitar, the homemade deacy amp and the rangemaster - I have the guitar and the rangemaster however until now I didn't have the amp.
So for this weeks project I have laid out the Greg Fryer designed version of the Deacy amplifier.

I got the 2 transformers from eBay - apparently people get "better" sounds from hammond transformers and you are of course free to try what you want but for mine I used the LT44 and the LT700.
according to various sources the speaker used is a 6" one with 4 Ohms impedance. the impedance is pretty critical to the sound of it, I didn't think it would be so vastly off but when I plugged it into an arbitrary 16 ohm speaker I thought it wasn't working correctly however I decided to change the speaker anyway and it sounds like it should.

it's also worth mentioning that this is a rare occasion where I laid out the stripboard and I made no mistakes, usually what I do is lay out a board then check a day later - usually find a few errors, then check another day later and so far this method has seen me with 100% success rate with stripboards

anyway the circuit is a pretty simple push pull amplifier that was used a lot in little radios during the 60's onwards  in fact it is very similar to a mullard 1 watt amplifier from that era.

Brian May says in various articles that he used a wah pedal to shape the sound along with his treble booster and microphone positions and if you move this thing in different directions you can hear how he got some of the sounds.
anyway on to the layout.

it's also worth mentioning about the whole positive ground thing, back in the olden days they used to have positive grounding rather than the more normal (now) negative ground. it's okay though even though it says -9v on the stripboard all you have to do is connect the negative to the -9v and the positive to the ground and it will work - this amplifier was originally battery powered so using pedals wasn't an issue however should you wish to use a power supply then you need to use a separate one to any pedals you have plugged into it or it won't work

inside the cabinet


  1. VERY cool !!! Curious to hear some soundclips !!!

    1. honestly, it sounds like the real thing - I will get around to sound clips at some point cause I will inevitably want to record with it

  2. Hi Paul,

    First I’d like to thank you . Thanx to share your experience.
    Sorry for my English (I’m French). I’m a Brian May addict ! I have a special red too (a Guild model) . Regarding “electronic” I’m a newbie , and I’ll start to do my first DIY pedals this Summer.
    I dream to make my own Deacy and your blog is perfect . So I have some questions to ask you (sorry if they are stupid).
    First could you please confirm me that red forms ,for exemple in d 15 , mean that I have to cut the stripe there .

    Second, the fryer web site use one AC125 , one AC126 and two AC 128.
    What can you advice me ? to use an AC126 or you think that the AC 125 is better here.
    If I can use an AC126, is this one could replace the Q1 or Q2 on your schema?

    Next question is regarding material.
    Do you think is better to use film capacitors or ceramic here ?
    And Regarding transistors except for R4 and R13 , does 1/4 w are ok ?

    And the last question (who really prove I’m a big beginner lol) , on the top of two of your transitors you have a kind of “hat” (I dunno the specific term) like black ventilator helix.
    Can you tell me what it is exactly and what it is use for.
    Is it like a cooler ?

    Thank you very much again, and sorry if I’m not pretty clear !
    Alain !

    1. bonjour Alain

      j'ai fabriqué mon deacy home made et quand je connecte la pile 9V sur le circuit, mon enceinte bourdonne ( buzz )
      J'ai vérifier le code couleur des resistances et sens des condensateurs et polarité des 4 transistors et tout est bon.
      Je compte sur vous pour pouvoir m'aider
      je passe des journée entière dessus mais je ne trouve pas pourquoi.
      Au niveau des soudures il n'y a pas de pont
      encore merci pour votre aide

  3. that's cool dude. I'll try and answer your questions the best I can.

    1. the little red squares are track cuts - I've been meaning to do a stripboard guide for questions like this.

    2. the reason I used the transistors I used is just because they were the ones I had and they are pretty much the same so the choice is yours, you can use what I used or the ones Greg Used.

    3. for authenticity you should use ceramic capacitors, you have to remember that the deacy was made from an old consumer radio (by Mullard) and in my experience mullard have always used ceramics for general purpose stuff and film for radio stuff etc.

    4. 1/4 watt are fine, that's what I used except for the ones specified otherwise.

    5. it's not too much of a beginner question, they are Transistor heatsinks and they aren't all that common these days (well they are on the power types but not the ones you see here) - they are needed for the 2 transistors you see them on because they are doing a lot of work.

    Never worry about asking questions, even if you think they are stupid. everyone has to gain the knowledge somehow - I have asked some pretty stupid questions in my life too!

  4. Thank you very very much Paul for your kindness and clear answers. (you corrected by yourself of course I did a mistake in question 4, was regarding resistors ;) )
    I can’t wait to make this project soon (first I have some pedals to assemblate), I hope I’ll have my Deacy for Christmas lol

    Regarding heatsinks, I’ll continue my investigations.

    For the AC126 , I’ll try to compare and understand your schema and greg schema in order to find where is the correct place (according to Greg’s plans). I’ll probably test different combinaisons.

    I started to search some speakers models on net. Hard to find too. For exemple Banzai Music propose a Jensen (CH615) 4 ohm (15w). This one seems to macth. But I’m not sure that is trade mark is good. Do you use a specific trade mark (maybe a celestion is too expensive for an 1w amp , isn’t it ? lol)
    Thanx Again !


    1. there was a speaker in the cabinet that I used, it was an old LEAK speaker cabinet and it just happened to be perfect.

      you can find transistor heatsinks on eBay - here are some that would fit those transistors http://www.ebay.co.uk/itm/Qty-5-TO5-TO39-Black-Anodised-Aluminium-Push-On-Transistor-Heatsinks-42-5C-W-/120852746684?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c236291bc

      then you just use pliers to squash them to fit the transistors.

      just remember that you are looking for hifi speakers not guitar speakers then it will be truer to what Brian May has and it will also be cheaper

  5. great ! Thanks Paul. You are true , i must not forget that the original was not done with a guitar speaker. Thank you for your link. now i think i have all to success !!!!! I can't wait to hear from you a sound demo ! i was looking for the original size of the cabinet and I found it on http://www.redspecialforum.com.

  6. Hello Paul,

    Graceful to your advices my project is starting.
    New step I’m buying parts.
    I already ordered LT400 and LT700 + heatsinkers (hard to find in france) from UK.
    I’m asking your help regarding several points because I’m really not sure to be right.

    1) Capacitors. I did a board cause I’m not confident regarding voltage of capacitors. Please find the following link : http://www.imagup.com/data/1160318895.html Do you think this choice is correct ? (I decided to use a film capacitor in C5 cause I have it now, maybe later I’ll replace it by a ceramic one)

    2) Resistors. Here all is clear for me I just have to take care to buy some 0,25w and some 0,5w (will be metal resistors)

    3) Transistors. I looked at your stripboard plan and the Greg’s one. If I want to respect the Greg’s schema AC126 is on your Q2 schema. So here no problem too

    4) Wiring. Here I have some question. First regarding how to wire the jack. If I’m not wrong, and if it’s like DIY pedals, I need to use a stereo jack for input. I noticed that input is on the “J” stripe . I really don’t know how to wire this input jack. Can you please tell me which stripes correspond to RING, SLEEVE and TIP. If im not wrong sleeve is ground so I have to connect it on stripe “K2” and Ring is audio so I have to connect it to the input stripe “J1” but I have no idea regarding TIP !!! lol

    Second I have some troubles regarding the speaker wiring. Is on D30 and H30. Could you please tell me which one is the positive and which one is the negative.

    And third regarding the battery wiring, is clear on your schema but I just want to be sure , could you please confirm me that I have to connect the positive pole to “K1” and the negative pole to “C1”

    5) Finally this is my last question !!!!!. I looked at KAT and Greg’s website, if I understood well they use an 8 ohms speaker. (and it seems on the original deacey is a 4ohms according to what you wrote). Could you please advice me regarding this ? Is it really important ? for you is better to use a 8ohm speaker (according to Greg) or try a 4 ohms ?

    Thank you very much Paul, I hope my English is not too bad ! I wish you a nice day !

  7. yes the caps are fine

    you only need a mono jack, in pedals the stereo jacks are used to switch the battery on and off.
    you wire the ground to the ring and the "In" to the tip
    the tip refers to the tip of the jack and the ring refers to the rest of it.

    regarding the battery wiring, what you said is right.

    different impedance speakers will make a lot of difference, I suggest you go for the one I said.

    with the speaker wiring it doesn't matter which way around they are connected because it is isolated with a transformer.

  8. thank you Paul ! Now i have all infos i need !
    FYI i'll create a "custom" deacy with an off/on switch, a volume button, an a led.
    I will create too an effect panel on his back, i'll insert 3 treble boost effects created by KAT (for 70's,80's and 90's and more Brian sounds)
    This effect will of course works directly on deacy amps but will be availabe like externals pedals for other amps (like the vox VBM1)

    you probably know this link : http://www.deacyamp.com/index.php?route=information/information&information_id=10

    I'd like to thank you again for all the support you gave me.

    As you know i'm a fan of BM. Actually i'm creating a french blog regarding this guitar heroe. I'd like to insert the link of your blog and talk about it. But before I would like to ask you your authorisation and agreement.
    Thank you very much and hope that mosquitos are all dead lol

    PS : I dl your album, congrats , it's really good, i like it !


  9. no, I'd never seen that site before, thanks for telling it to me.I look forward to seeing your blog and if you link me I shall link you, I'm always interested in adding links to foreign sites of interest to my site plus I spent a good deal of time in france so it's a place I like. I can actually understand french when people verbally speak it to me but I'm not so good at reading it.

    just remember when you build this to take it very slowly, check and recheck and make sure you check my blog entry about working with stripboard
    you probably won't need a volume control because the amplifier is quite quiet, instead put your volume on the treble booster.
    yes. the mosquitos are dead - little fuckers!

  10. yeeeeaaah kill 'em all :))

    Regarding the volume pot is more for "decoration"! Is not a real one!!! it will just have an effect on the guitar volume entry, i did a little wiring schema here : http://nsa29.casimages.com/img/2012/08/25/120825023659388779.jpg
    Regarding treble boost effects , i think it will be more useful (cause will have an effect on amp if i need it and could be use like external pedals , in this case the deacy will be in off position). I'll replace the footswitches 3PDT with toggle switches 3DPT (on/on)

    All treble boost will be plug on a 9v battery in "paralell"
    The rear panel will look like this : http://nsa30.casimages.com/img/2012/08/27/120827094857393149.jpg

    Sure i'll take my time and check everything. First i'll do a deacy for a friend (will be my training !!) in one or two weeks. Will be a basic version without led/volume pot/switches and effects.

    The KAT website propose a deacy schema too. Is very close from the greg's one. I've just noticed some differences regarding capacitors. KAT do not precise which transfo is good to be used (probably because they sell their own transfos lol). They sell speakers too(8 ohms).On the KAT schema they precise that a speaker of 4 ohms to 16 ohms could be used !!!!

    My blog is very new... i've just buy the domain name today, i'll have lot of work to do on it, i hope it will be really available in one month. BM blog does not exist here in France. Will be the first one.
    The domain name is just http://brianmay.fr/ very easy to remind it :))
    Thanx for your agreement , i'll add your blog in my link page and i ll probably talk about your stripboards creations in DIY section ;)

  11. Hi Paul !
    I wish you are ok !
    I did my first Deacy !!!!
    I was scared cause the first time i plugged the guitar no sound get out !!!
    I check it again and some solders were bad on a transi and on one cap.
    So now it sounds !
    This first model is for a friend (without custom options)
    So thank you for all your help !

    Unfortunately i did not order a 4ohms speaker , i had a 8 ohms home, so i tried with it.
    It sounds good. i really dunno if i have to buy or find a 4 ohms speaker ...
    I saw in some DIY forum that for a transistor Amp the impedence will just change the sound volume without changing the sound "colour"... I saw you did another "experience" with impedence choice... What do you think is better to do ? it really not affects the sound colour? It seems was different for you no?

    Thank you Paul

    Ps : i have make the cables shorter cause they do "antena"!bzzzzzzzzzzzzzz lol
    this is a pic of it :



  12. well impedance in speakers within a certain order of magnitude will affect how it sounds however if you like how it sounds with what you have then leave it, but remember that it will sound different once it is in a cabinet.

    I'm really glad it worked for you, I shall post your picture on my site for others projects and I hope you will send me a picture once it is completed. if you find you are getting buzzing, try putting the board inside a metal box before you mount it in the cab.

    now you have a working one you can make an experiment one and try out different transistors and mods to see what you can get. but again I am very happy it worked for you.

  13. is graceful to you Paul ;)

    Yes , of course i'll give you some news when it will be finished. Now i have to do my "Deacy" this one was for a friend. Regarding "my" Deacy it will take more time because i'll do it with my "old" father who is an expert on "wood matter"!!. Sure i'll send you pics !!!
    Now i'll try to isolate it (i'll follow your advices) and i'll work on my own Deacy with "options". I'm really curious to try how it sounds with a 4ohms. So i think i'll buy a another speaker for my own amp.
    I ll continue to follow your blog especially regarding guitar effects and sounds (i had already lot of treble booster) cause i'm really glad regarding the result i had with your stripboard plan !

  14. hi,

    is it necessary to put transistor within certain range of hfe (like we did with fuzz or treble booster) in this circuit?

    thx & God bless!

    1. ok, so I can put transistors with random hfe in this circuit an it will works fine?
      or maybe there is some guideline regarding transistors selection?

      thx & God bless!

    2. yes,the guideline is pretty much the name of the transistor
      it doesn't need to be matched or anything like that, they just need to be working

    3. ahhh, thank you for the info I'm ready to build this one.

  15. Hi Paul !
    I hope you are fine.
    I come back to you in order to give you news about my Deacy amp .
    I finished my Original Model !!!
    You'll have all details and pics here :
    I'm very glad regarding the result , the look and sound !

    Thanx again for your help.
    Do you know is a software exists in order to create a PCB from the original schema ?
    Thank you very much !


    1. I use EAGLE for PCB design and the schematic layouts (when I don't hand draw them)
      your deacy documentation looks cool, I'm happy that people are building stuff from my site
      someone called Chris May (^up there)was trying to get in contact with you because he had a little trouble with english. did he get through to you?

  16. yes yes Paul, it's ok he contacted me !I'll see it with him directly :). I'll try to see how Eagle looks thank you !

  17. The circuit you used differs in some respects from the circuit posted on the Knight Audio site (http://www.deacyamp.com/download/KAT_Projects/KAT%20Deacy-Style%20Amplifier%20Unit%20Project/KAT%20Project%201%20Watt%20Deacy-Style%20Amplifier%20Unit.pdf), though that one doesn't propose to be the true Deacy circuit.

    Where did you get the circuit you used, and is it closer to the real Deacy circuit (or maybe even THE Deacy circuit)?

  18. PCB some pictures for those who wish to print and use sensible picture.
    sorry for my English language.
    Thank you.

    1. Hi,

      Do you happen to have a .brd file so I could have a PCB fabricated?

  19. Can you use a regular 9volt battery? or do you need the large pp9 9volt? I am confused with this part, I see that the real Deacy uses a pp9, but I am using your schematic so could you please verify this info for me? And thanks for posting this vero layout, I am now Deacy obsessed!

  20. Hi Paul. I'm finally moving onto my next build after building the treble boosters you have on your site (all great) as well as some others, and the Deacy amp is the choice. So I'm now sourcing the components and one modification I would like to make to the Deacy is a DI output. Do you have any suggestions how this could be achieved? Could the schematic be modified to be a Deacy sim in a pedal or as I read earlier, the speaker is a big part of the sound?

  21. Hello,
    What is the gain (Hfe) of each transistor? I can not find information about it.

  22. Hey Paul, thanks so much for posting this circuit. I just recently built it and it sounds great! One little problem though, as the note decays the distortion fizzles out fairly quickly. Also if I strum the strings lightly no sound gets through at all. Do you have any suggestions for adjustments I could make to mitigate the problem?

  23. Hi Paul,

    I recently purchased the Xicon transformers, which are a bit beefier than the Eagle trannys but still significantly less power than the 1w in KATs Deacy.

    Would the same cap and resistor values specified here work with the substituted transformers?

  24. Hi there. Can you advise me as to which way the caps should be facing? I'm new to this and struggling a bit and really don't want to blow anything up.