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|