Deacy Amp (?)

[Ivana]

Hello!
I want any information abot subject. (Original, not Vox BM spec or same...)
All that you know: 2 transformers or not, 4 transistors or 3, common E or common B output push-pull and its class of operating....
The best will be if anyone shows me the scheme! 
Thanks!

[Mark Hammer]

Which one?

From the Guitar Player review a year or two back, it would seem that the version Vox released is slightly different from the one-of that Roger Deacon made for Brian May.

[Strat Cat]

Which one?

From the Guitar Player review a year or two back, it would seem that the version Vox released is slightly different from the one-of that Roger Deacon made for Brian May.

That would be John Deacon

[Ivana]

Which one - original with Ge and transformers...
As I know, all of the Vox recent amps (BM spec, "Deacy"  and others) does NOT have signal transformers but "simulations"...

[Strat Cat]

Here's what I was able to find on the amp.

Deacy Amp

[Ivana]

Thanks, I know this page.  But can you give me "Mullard Reference Manual of Transistor Circuits (see pages 168, 170 and 171)." 

[Vsat]

Ivana,
Just so happens that I have a 2nd Ed. 1961 "Mullard Reference Manual of Transistor Circuits" sitting beside the computer right now... anything in particular you want to know? (as for the Deacy amp, I don't know anything about it).
Cheers, Mike

[R.G.]

From reading that description, the Deacy amp is quite similar to the circuit in my battery powered Pignose - driver transistor, output transformer, etc, except perhaps for germanium transistors.

[12afael]

http://www.plexilandia.cl/foro/viewtopic.php?t=2426

on my forum the father of a member build an SS amp and sound really close to the May sound. check the samples.
is on spanish but the music is universal

 

[Ivana]

Greg Fryer says that original Deacy has 2 (two) transistors in driver stage and "John said the amp possessed a warm and pleasant (and partly distorted) sound". During my lot of experiments with a couple of circuits OF 2 transistors it is too much gain WITHOUT a feedbacks!!! OR normal gain with 1 driver transistor! And I dont know wich feedbacks was in subj (local, overal etc...) And what was the 2 trannys arrangement - Cap coupled or direct like in Fuzz Face??? Too much questions! But if the OUTPUT PP was COMMON BASE design 2 trannys in preamp gives normal sound!  .....

Vsat - can you give me an examples of typical (better all  ) 2-transformer amps schematic of those era??? Wich can be used as a car radio... 0.5 watt...

R.G. - "driver transistor".... 1? OR 2?  If 2, the first cn be an emitter follower but if it was right, the sound was not "lacked brilliance or much definition" and have not 12 kom input R! The input transistor imho was common E! And the second in preamp too.

12afael "is on spanish but the music is universal"  I am russan and I have some difficulties with english language on this forum! But I want an information and "Now I'm here....." (C) 
But I can not open your page... 

[12afael]

Ivana, the page is working, here are the samples

http://www.endor.cl/daniel/killerqueen.mp3
 
 http://rapidshare.de/files/4774380/Killerqueen.mp3.html (if don´t work the first)

 http://www.endor.cl/daniel/GOFLB.mp3
 
 http://rapidshare.de/files/4799814/GOFLB.mp3.html

I suppose that the first tranny is for coupling the first stage two the power. transformer was used instead of capacitor on the tube era for coupling stages.

I don´t think that the vox is a real copy of the Deacy 
this is the original
"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."
and this is the vox
"The Brian May Special is a 10 Watt, 1 x 6.5"

probably they get out the transformers .

listening the samples above I think maybe the low power amp is important . this amp is an 8 watts and probably the cliping diodes on the distortion stage are germanium.

if the power is of one watt you need a speaker of 2 watt maybe? hard to get I think

[12afael]

"The Brian May Special Amp combines the best aspects of the Deacy Amp and Brian's own treble booster, but also has the extra added features of controls for Gain, Tone, and Volume. The original system had no controls. The Brian May Special Amp also has a 6 ½ inch speaker and puts out 10 watts. The original Deacy Amp supposedly put out 0 .45 watts of power. The Booster Output jack on the Brian May Special Amp permits you to overdrive the amp section of another amp, and it supposed to exactly replicate the sound of May's unique system, even down to a battery simulation circuit that supposedly replicates the unique sound characteristics of a "system" driven by batteries. A couple of very desirable extras are an external speaker jack and a recording/headphone jack. "
I found this here.
http://www.epinions.com/content_195597602436

0.45 watts that is nothing!!! a cheap 2n3904 have more power...
 

[Ivana]

I have read a manual of the VOX BM spec.... http://www.voxamps.co.uk/downloads/ ...R.G. is right - battery powered Pignose is more close to Deacy than VOX  
"probably they get out the transformers" - yes.
"... cliping diodes on the distortion stage ..." - I beleive that diodes can not make the sound better. I like overdriven Push Pull stage. Even based on transistors...

the power is of one watt is not the aim. The aim is with battery power get an overdriven output stage WITH MAXIMUM "R~" (?) between the collectors. But this occurs if the output power will be as small as possible....

[Ivana]

"0.45 watts that is nothing!!! a cheap 2n3904 have more power... " - when I make a maket subj amp with 0.5 watt and connect it with NORMALL Db guitar speaker I was needed to make an attenuator! 

[Killer Queen]

I have the VOX deacy, and from the techinal notes in the back of the manual, it's quite clear that the circuit is miles from the original (for example, Ge trannys have been replaced with Si trannys- all sorts of things like that), although the sound itself is close enough.
 From what I remember, the original was based on a PCB/circuit that John Deacon found in a skip- most likley a hi-fi circuit. The guitar couldn't really drive it well (due to input impendance or some such thing), but when Brian tried it with the TB, it distorted nicely, and Deacon put it in a cabinet with speakes. (Cant remember if they were hi-fi, uitar, or one of each.)
 Ah, here we go: http://www.brianmay.com/brian/briannews/briannewsjun05.html

A year or so ago, I was concidering having a go at making my own deacy amp, and sent an email off to the only person I could find on the web who has a homemade one- Martin Pitcher- Brian May guru extrodinaire. He sen't me back a circuit which he said was `probably not the exact same circuit but may well be similar.` (Can't remember what his damn site is! It has some samples of his amp. I'll let you know if I remember.)

Anyway, feel free to drop me an email (tusk_sam@hotmail.com) if you want a copy of the scematic, or want to host it somewhre (or put it in the image gallery, which i don't have teh slightest idea how to do  ) It's in pdf format- about 0.14Mb. Quality isn't great (it seems ot have been scanned), and I think bits may be missing, but it'll probably be interesting nevertheless. Has 4 trannys- all germanium, I think. (OC81 OC81 OC71 and OC81D?)

[Ivana]

Killer Queen please, send me a copy of the scematic (and anything else if you can): Ivana_2004@mail.ru
Great thanks!!!   

[12afael]

thanx killer queen!!
it look close to the deacy on design, 9V , 2 transformers, germanium transistors, only one control .

cristal pick up . probably it was a turntable amp.
the problem are the transformers. I can`t even imagine the size of the core.

[JimRayden]

I went out and test the Brian May Vox. The clean channel was great and gave a great overdrive when pushed hard. But the second channel.... Never heard a worse guitar sound in my life. Very fizzy etc. Dunno what the reason could have been...

--------
Jimbo

[Killer Queen]

I've heard that some of the deacy amps have a broken high-gain sound.
Apart from that, it may just be what you're putting through it. Certainly, putting something like a strat would sound pretty dreadful (I think)- it sounds best only with a humbucker-equiped guitar. (Or, in Brian May's case, Single Coils in series.)
 The amp IS, on the highgain channel, stunningly noisey, and indeed pretty fizzy, so even with the right guitar and everything it would sound pretty dreadful to a lot of people. Playing the bottom strings/low notes sounds great though (IMHO)- really creamy and cello-like.
 Note that Brian used the deacy pretty much only for harmony work. (The more you layer it up, the less you hear of the fizz etc)- it sounds very good like that. Queen/Brian's version of `god save the queen` for example, or "procession" from thier second album, or the harmonies on `Killer Queen`. If any of you have the `Night at the opera` album, go take a listen to `Good Company`- all those clarinet sounds, trombone sounds, trumpet sounds etc were done with the deacy recorded with various pickup settings and in different ways. (With a coat over it to dampen the sound, for example.) A great studio toy. But the deacy sound is little use outside of the studo. (Having said taht, the VOX deacy has some jolly good sounds on the low-gain channel.)

What I'd love to do, if i ever get the money, is to buy/build 3 deacy amps and hook them all up to a harmoniser- Instand BM harmonies- that would be great fun 

[Dave_B]

Ah, here we go: http://www.brianmay.com/brian/briannews/briannewsjun05.html

What a great article.  Thanks, KQ.