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! :icon_smile:
Thanks!
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.
Quote from: Mark Hammer on October 12, 2005, 04:44:05 PM
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 ;)
Which one - original with Ge and transformers...
As I know, all of the Vox recent amps (BM spec, "Deacy" :icon_lol: and others) does NOT have signal transformers but "simulations"...
Here's what I was able to find on the amp.
Deacy Amp (http://www.brianmay.com/brian/briannews/briannewsjun05.html#32)
Thanks, I know this page. :icon_smile: But can you give me "Mullard Reference Manual of Transistor Circuits (see pages 168, 170 and 171)." :icon_wink:
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
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.
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
;D
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! :icon_rolleyes:.....
Vsat - can you give me an examples of typical (better all :icon_smile:) 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? :icon_neutral: 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" :icon_lol: 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) :icon_lol:
But I can not open your page... :icon_sad:
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
"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...
:icon_eek:
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 Â :icon_rolleyes:
"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....
"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! :icon_rolleyes:
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 :icon_biggrin: ) 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?)
Killer Queen please, send me a copy of the scematic (and anything else if you can): Ivana_2004@mail.ru
Great thanks!!! :icon_biggrin: :icon_cool:
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.
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
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 :icon_biggrin:
Quote from: Killer Queen on October 13, 2005, 12:52:32 PMAh, here we go: http://www.brianmay.com/brian/briannews/briannewsjun05.html
What a great article. Thanks, KQ.
Aha! The link to martin pitcher's site!
http://homepage.mac.com/martinpitcher
Thanks to the chap who posted that over at the BrianMayworld forums.
There's one or two sound samples of his home-made deacy on the site. (Presumably based on the same schematic that he gave me.)
Friends, Killer_Queen has granted www.pisotones.com to host this file for all of you:
Deacy (http://www.pisotones.com/Deacy/Deacy.pdf)
Hope you enjoy it and thanks to Killer_Queen and Martin Pitcher.
What kind of transformers are these?
???
Quote from: vanessa on October 14, 2005, 03:49:18 PM
What kind of transformers are these?
???
Yes, anyone knows about this data? or any primary/secondary impedance?
Thanks so much.
the speaker is 5.3 ohm???
they are a couple of rare value 3-3ohm , 5-6k, 2-2k are 3.3, 5.6k, 2.2k????
if someone have a couple of small radioshack audio transformer could test if they works. if we have luck they have the same impedance .
if the power is 0.45watt. and the output of a pick up is 100mV I think is very easy to overdrive this amp.
I think it's not "5.3 ohms" but:
L.S.3 ohms
that is... Loud Speaker 3 ohms :icon_wink:
There's some more info over here if anyone wants to look:
http://www.voxamps.co.uk/downloads/VBM1_E1.pdf
At the back of the manual, in the `Technical talk` section, it says a few quite interesting things.
QuoteAs already mentioned in DETAILS at the beginning of this manual, the original amplifier itself dates back to a Mullard circuit that was published when transistors first became vailable as a consumer product, and was probably “rescued†from a car radio, as it is built on a commercial printed circuit board. The amp features the total amount of four germanium transistors â€" two for the preamp and driver stage, and two for the push-pull output stage. The circuit also has an inter-stage driver transformer (between the driver transistor and the pushpull pair) and also an output transformer from the output stage into the speaker. When connected to a 9 Volt lantern battery the amp produces a massive 0.45 Watts output.
The amp circuit-board was mounted into a 1960’s contemporary bookshelf HiFi speaker cabinet, of quite small proportions (England’s bookshelves were not very big at the time!), and contains a small woofer loudspeaker and a cone tweeter that is coupled through a capacitor. Due to the speaker technology of the time (and having been played for many years by Brian) it has a relatively mellow sound when compared to today’s hi-tech, hi-fidelity speaker systems. As it happens, said mellowness is actually quite complementary when the original Deacy is used in conjunction with Brian’s homemade guitar and Treble Booster. Due to the very low input impedance (12kOhms) of the amp John Deacon salvaged from a pile of rubbish (remember, in all probability it was originally designed for use in a car radio), it is actually not very useable when a guitar is plugged directly into it. This is because guitar pickups need to see a much higher impedance in order to do their job properly. Hence the use of Brian’s homemade Booster pedal was vitally important, not only in terms of tone but also in terms of the overall compatibility of the signal path.
It also mentions that the speakers used are no longer available.
That schematic is the same one shown on Fig.4, page 171 of the 1961 Mullard manual.
The transformers are identified in the text as Colne 06005 (for T1) and Colne 06006 for T2.
The equivalent Hammond transformers are listed in the back of the manual as 57318 and 57319.
Maybe someone has an old Hammond catalog that lists the specs?
Text also states that this amp is the same as the one shown in Fig.13, page 160, (but with the preamp added).
Fig.13 has some further transformer info:
T1 is 3.5:1+1, Rp < 130 ohms, each half of the tapped secondary has Rs < 40 ohms.
T2 is 3.1+3.1:1, each half of the split primary has Rp < 1 ohm, Rs < 0.2 ohm.
Speaker is 3 ohms.
The OC81D driver and OC81 matched pair were supplied as a set by Mullard.
Cheers, Mike
Thanks for the info.
The transformer that connects oc81d, it's a driver transformer? Maybe an old spica driver transformer will do that work!
T1 functions as the driver transformer, probably a safe guess is that it was sold as a driver transformer(?). Wonder if this thing is all that different from those little one-watt germanium amplifier boards that Radio Shack used to sell in the 70's?
Mike
Thanks a lot all of you! :icon_smile:
Sorry for my offline - I was in a tour...
Now I will try this scheme in my perfboard witn my old different russian germanium transistors! :icon_cool:
Hello everybody,
I agree with JimRayden, the clean channel was great and the second channel is very fizzy, but with a cabinet and a another "treble booster", that changes all ! (please, visit my website for more informations: http://www.ccm.fb.bz ).
This Deacy project is very interesting, but for the moment i don't find the transformers and the OC81D.
Christian.
The transformers are probably something like these old 'Eagle' standbys, the LT44 and LT700:
http://www.maplin.co.uk/Search.aspx?criteria=eagle%20LT700&doy=18m10&source=15 (http://www.maplin.co.uk/Search.aspx?criteria=eagle%20LT700&doy=18m10&source=15)
One is a driver transformer, the other output. Can't remember which off hand, and Maplin can't be bothered to say, but the answer is surely only a Google away.
The specifications for the maplin transformers are as follows....
Type No. Application Primary Secondary
impedance impedance
LT44 Min TR LT44 Driver 20kΩ 1kΩCT
LT700 Min TR LT700 Output 1·2kΩCT 3·2Ω
Hope this helps, look forward to hearing if anyone has built one/building one, and seeing if the schematic works and with which transformers.
I don't have understand..... ???
Whati is the value of T1 and T2!?
And where I can find the transistors OC81 and OC81D!?
TNX
after doing a little reading i wonder if one of the old fender interstagetransformer would work for this circuit. i have one if anyone wants it. i have not use for it.
ed
I have test this scheme yesterday. With different russian transistors and transformers. With the treble booster in front of it. Sound is good, but very depends from:
- transistor's gain.
- value of the first input resistor (i remove the cap - I have it in a booster).
- value of general feedback resistor. I remove it.
- transformers and its parameters!
"T1 is 3.5:1+1, Rp < 130 ohms, each half of the tapped secondary has Rs < 40 ohms.
T2 is 3.1+3.1:1, each half of the split primary has Rp < 1 ohm, Rs < 0.2 ohm."
is not agree with
"LT44 Min TR LT44 Driver 20kΩ 1kΩCT
LT700 Min TR LT700 Output 1·2kΩCT 3·2&ohm"
what is true?
Ivana,
I only posted the spec of the maplin transformers as Ge_Whiz was asking what spec they were. I doubt that they are what is needed though as the figures are a lot different to that stated in the mullard manual.
Be interested to hear any sound samples of your deacy.
hello everybody,
I contacted many manufacturers of transformers.
Unfortunately, none did not answer favorably.
For the moment, I have not solution.
Christian.
Quote from: Ivana on October 25, 2005, 03:52:49 AM
"T1 is 3.5:1+1, Rp < 130 ohms, each half of the tapped secondary has Rs < 40 ohms.
T2 is 3.1+3.1:1, each half of the split primary has Rp < 1 ohm, Rs < 0.2 ohm."
is not agree with
"LT44 Min TR LT44 Driver 20kΩ 1kΩCTÂ
LT700 Min TR LT700 Output 1·2kΩCT 3·2&ohm"
what is true?
It looks to me like Rp and Rs are DC resistances, whereas the specs for LT44 and LT700 are impedances - very different beasts.
I think that "3.5:1+1" is not Rp and Rs are DC resistances but a relation ("/" :)))) of the... coils? spirals?... :icon_redface: my bad english...
The "3.1+3.1:1" is the voltage (and turns) ratio of the windings. If you put 1V on the "1" winding, then 3.1V will appear on each of the other two.
The Rp and Rs numbers are indeed the DC resistance of the copper in the windings. This has little to do with the turns ratio or impedance ratio.
The impedance ratios are yet another way of describing the same transformer, and possibly more useful. They describe what impedance appears at the primary winding if the specified loading is applied at the secondary. That is, the "1.2Kct to 3.2ohm" specification promises you that if you put a 3.2 ohm resistor on the secondary, then whatever drives the primary will think it's a 1.2K ohm load.
The turns ratio and impedance ratios are related. The impedance ratio is the square of the turns ratio. So in the case of a 3.1+3.1:1 transformer (voltage) you'd have a
(3.1+3.1)squared to 1 impedance or 38:1 impedance ratio. If the load is 3.2 ohms, then the primary load is 121.8 ohms.
The real "doesn't make sense" in this case is that the voltage ratios and the impedance ratios don't relate by the squared function.
Hello everybody,
OK Ivana, it's very interesting but what is the impedance values of the OC81D and voltage or impedance values for the T1 along with power ratings for both transformers ?
I think that "impedance values of the OC81D" is not exist as a parameter. It is not a pentode. The main aim is to preserve the power overloading of the transistor.
does anyone know where this diylc file might be?
http://diy-fever.com/wordpress/wp-content/uploads/2012/08/component_layout.png
Also check out knight audio technologies Deacy amp. This is the kit I bought and was my first DIY project last Christmas and I haven't stopped learning since
Kipper4 :
did you get the trannies there.? they seem a little steep.
are they different what most are using for this kinda app.
>>>
WARNING! There are a number of third party transformers for sale on the internet. Some are configured incorrectly with the primary coils of the interstage transformer reverse-wound. In this instance, the amplifier will not work correctly untill you swap over the primary connections. A number of these transformers, and some claim to have been tested in the actual Deacy circuit, are also of the wrong turns ratios, which, causes too much gain within the amplifier stages.
>>>
an ok deal on PCB and components though.
are they geranium transistors?
No i did not use the transformers sold by KAT. Yes they are a little steep but i wish i had used them now.
I used some bought from ebay in eastern europe.
Any yes they are configured differantly i had to swap 2 legs over on the transformers.
it sounds good but i think it could do better with better qaulity built transormers. IMO.
Quote from: Kipper4 on August 04, 2013, 02:50:37 AM
No i did not use the transformers sold by KAT. Yes they are a little steep but i wish i had used them now.
I used some bought from ebay in eastern europe.
Any yes they are configured differantly i had to swap 2 legs over on the transformers.
it sounds good but i think it could do better with better qaulity built transormers. IMO.
Rich,
just out of interest: what did you use for a speaker/cabinet?
david
I had an old hifi (6" speaker and 2" tweeter) in the loft from an old 8 track my wifes father passed onto us.
I used it because i wanted that small speaker thing that mr May did with his.
I took the back off and put the circuits inside and screwed it back on.
I say circuits because i also built the KAT direct record/headphones circuit and an integrated treble booster.
The treble booster was an old supposedly brian may treble booster traced one unfortunately its ground positive so i have it supplied by a battery that clips on the back of the cab.
i put plugs to go in and out of the treble booster and an amp direct jack too and use a short patch cable on the back to put the treble booster in line.
A friend did a simultanious build and used a single wallwart power supply for both amp and treble booster but used a max1044 i think it was to reverse the grounds for his treble booster but he had a lot of problems with it before he did a similar thing to me and gave them there own power supplys as they didnt want to play well together as he had them.
I also have the possibilty to use a pp9 battery supply for the amp (lead sticking out the back of the amp) Should i ever decide to take up busking.
:)
The Fryer Sound Deacy Amp sounds really amazing and it is so close to the sound of a good tube amp.
Check out my demo here:
https://www.youtube.com/watch?v=PnNJfHTxliw (https://www.youtube.com/watch?v=PnNJfHTxliw)
Nice sound. I wish you had played with the guitar volume though.
I guess your not using a treble booster since you say no effects then?
Those pups sure sound good too.
Sweet
Rich
Thanks, see the second part from Clean to Overdrive by just rolling up the volume guitar pot below (there is no treble booster):
https://www.youtube.com/watch?v=CjHgcS4tPqQ (https://www.youtube.com/watch?v=CjHgcS4tPqQ)
Did you get the fryer transformers in there too?
Yes there are two Fryer transformers in the circuit.
Sorry for the broken links, please find my demos of the Fryer Sound Deacy Amp here:
https://www.youtube.com/watch?v=zQ5xuR0N_fo (https://www.youtube.com/watch?v=zQ5xuR0N_fo)
https://www.youtube.com/watch?v=o8VL64gORKw (https://www.youtube.com/watch?v=o8VL64gORKw)
Hi,
I am looking into building a Deacy replica from Paul Stevensons stripboard layout.
https://paulinthelab.blogspot.com/2012/06/brian-may-deacy-amplifier-stripboard.html?m=1
He states this is based off of Greg Fryers design...but wasn't Fryer the one who developed the KAT build along with Nigel? Because this layout is much different than the KAT schematics (which looks similar to the original mullard layout). Either way there seems to be much misdirection and misinformation surrounding the legend.
I didn't want to use the Eagle transformers because their output seems a but low. And I have i ohm drivers lying around so I settled on the Xicon trannies from Mouser..which are still significantly lower output than the 1w specified
http://www.mouser.com/Search/m_ProductDetail.aspx?Xicon%2F42TU048-RC%2F&qs=LQJGOuQCHKR6gBOQxy1apw%3D%3D
http://www.mouser.com/Search/m_ProductDetail.aspx?Xicon%2F42TM024-RC%2F&qs=%252bLh6ltJumVS5xwocZBTZJg%3D%3D
My question (forgive me I'm green and still learning)....does the topology of the layout have to change? Or are trannies with similar specs interchangeable
Hi. Could you please share the links for the Mullard and the KAT?
Quote from: nickbungus on October 04, 2016, 08:11:42 AM
Hi. Could you please share the links for the Mullard and the KAT?
Knight Audio : http://www.deacyamp.com/ (http://www.deacyamp.com/) have a look under the 'Project room' for the Deacy-style amp stuff, there's a few downloads... The amplifier kits and transformers seem to have disappeared from the shop pages though, so possibly they might not sell them any more... :(
david
*edited for clarity
FWIW... I built mine with the transistor set from Ebay, and the Eagle transformer set from Ebay. Actually only used the first two transistors from the Ebay set (AC125 / AC126), opting for a matched pair of AC128K's that I had on hand for Q3/4. Used the schematic from the Vox Deacy, along with a Fryer boost on the front end.
(http://www.gitaar-in-tune.nl/images/Schema%20Gitaar%20in%20Tune%20Deacy%20amp.jpg)
http://www.diystompboxes.com/smfforum/index.php?topic=105657.0 (http://www.diystompboxes.com/smfforum/index.php?topic=105657.0)
I had to build +/- power supply onto the board to deal with the NPN/PNP deal, but no big deal. The most important element after the circuit is the speaker. I tried three different 8" whizzer cone speakers, and I found that the cheapest paper cone you can possibly find, is the best. Paper throughout works best. I tried one with foam edging, and it was totally wrong. It just doesn't project the midrange frequencies properly.
For missing web pages, if you have the page address, try the Wayback Machine. You might get lucky.
Quote from: nickbungus on October 04, 2016, 08:11:42 AM
Hi. Could you please share the links for the Mullard and the KAT?
Nick,
In addition to my earlier comment, the Mullard 1W amplifier schematic appears on page 171 of the "Mullard Reference Manual of Transistor Circuits Mullard Ltd 1st ed 1960" (I was able to find a PDF download quite easily).
david
I bought those LT44/700 transformers from Maplin in the UK. IMHO they are too small for this circuit. They work but the output transformer impedance ratio drops a lot of volume.
If you ask me, I'd buy old radios from the 60s with bigger transformers. You could remove the transformers or, if the radio has an AUX input, you can overdrive the input with a TS or RM or whatever.
That's what I used to do when I was a little kid, I pluggled the guitar into the MIC of a Pioneer stereo, and pushed the AUX input of an old Crown radio recorder via the headphones OUT. See my gallery.
mac
Quote from: mac on October 05, 2016, 09:50:02 AM
I bought those LT44/700 transformers from Maplin in the UK. IMHO they are too small for this circuit. They work but the output transformer impedance ratio drops a lot of volume.
If you ask me, I'd buy old radios from the 60s with bigger transformers. You could remove the transformers or, if the radio has an AUX input, you can overdrive the input with a TS or RM or whatever.
That's what I used to do when I was a little kid, I pluggled the guitar into the MIC of a Pioneer stereo, and pushed the AUX input of an old Crown radio recorder via the headphones OUT. See my gallery.
mac
The Mouser transformera seem to.havw a bit better output...i bought them really for impedance matching. Im going to be using the amp for studio use only really for tone as opposed to loudness
I know that RG's site had a nice tutorial on how to test gain and leakage on the transistors..
Is there a comprehensive reference on how to bias them as well? Perhaps for the transformers too?
Mouser has better options, xicon IIRC.
You could try replacing one the base resistors of the driver transistor with a pot, say the one from vcc to base, and adjust for optimal sound.
And use a pot instead of the fixed 2k2 at the power stage to get the optimal current at the base of the power transistors. Beware of too much current, you could burn your Germs.
mac
Quote from: mac on October 06, 2016, 02:01:08 AM
Mouser has better options, xicon IIRC.
You could try replacing one the base resistors of the driver transistor with a pot, say the one from vcc to base, and adjust for optimal sound.
And use a pot instead of the fixed 2k2 at the power stage to get the optimal current at the base of the power transistors. Beware of too much current, you could burn your Germs.
mac
(https://2.bp.blogspot.com/-CIf5yPKau7w/T-zGQZzpfwI/AAAAAAAAAts/19X_1pKaUP0/s1600/deacy.bmp)
hello Mac
could you please be more precise about the 2 resistors you are talking here ?
You could try replacing one the base resistors of the driver transistor with a pot, say the one from vcc to base, and adjust for optimal sound. R6 ?
And use a pot instead of the fixed 2k2 at the power stage to get the optimal current at the base of the power transistors. Beware of too much current, you could burn your Germs.R10 ?
the bias is supposed to be on R13
thanks for you help
Yes, R6 (or R7), and R10.
Warning, if you lower R10 too much you could burn the power transistors.
I wouldn't change R13.
mac
thanks for your prompt reply
my issue is that the note fade out in a strange way, like there was a noise gate
i read it was because of mis-bias so i'll try with 2 trimpots on R6 AND R10
any advice is welcomed :)
Check Q1 too.
mac
3 trimpots, i guess it will not be easy to tune haha
do you remember if you made the fryer (image below ) or the KAT version ( http://www.deacyamp.com/download/KAT_Projects/KAT%20Deacy-Style%20Amplifier%20Unit%20Project/KAT%20Project%201%20Watt%20Deacy-Style%20Amplifier%20Unit.pdf ) ?
byod = build your own deacy?
lol
never thought about that,
it s "bring your own device"
very bad nickname when you are not inspired
Quotedo you remember if you made the fryer (image below ) or the KAT version (
Mullard schematic.
However I'm using a National radiorecorder which sounds louder and similar :)
Actually, the Deacy is a Supersonic PR80 and the output transformers seems to be an autotransformer. Some day I'll wind my own.
mac
sorry for wake up post, cause I want a bit more complete information
from fryer site
https://fryerguitars.com/deacy-amp/ (https://fryerguitars.com/deacy-amp/)
project from github by jareklupinski
https://github.com/jareklupinski/deacy-amp (https://github.com/jareklupinski/deacy-amp)
The Mullard and PR80 is different a specially at output, the transformer is different
the bias trim like slide pot, from other forum
https://groupdiy.com/threads/deacy-amp-transformers.78997/page-2 (https://groupdiy.com/threads/deacy-amp-transformers.78997/page-2)
I trace pcb but dont know the size of it probably 10 x 6 cm
(https://i.postimg.cc/PpzcfSD4/Deacy-Amp-Pcb.png) (https://postimg.cc/PpzcfSD4)
For silicon transistor would it be the same?
The speaker I found so far would it be work?
https://resources-boschsecurity-cdn.azureedge.net/public/documents/LHM0606_00_US_Data_sheet_enUS_1945383179.pdf (https://resources-boschsecurity-cdn.azureedge.net/public/documents/LHM0606_00_US_Data_sheet_enUS_1945383179.pdf)
Also I wonder the transformer that make a good sound, cause tube amp are OT also?
Hi,
That speaker, looking at the datasheet, has a high impedance, for use with a 70 volt line transformer. You need a 4 or 8 ohm speaker, depending on your output transformer. Get one with high efficiency if you can (that is the dB number in the specs).
Amplifiers with output transformers, tube or transistor, produce a special distorted sound when overdriven. Has to do mainly with the magnetic field through the transformer core collapsing at overload, and the limited frequency response.
Also, germanium transistors sound different from silicon in these applications.
Hi Mr. Clint, thank you for reply
Quote from: Clint Eastwood on June 06, 2022, 04:10:23 AM
Amplifiers with output transformers, tube or transistor, produce a special distorted sound when overdriven. Has to do mainly with the magnetic field through the transformer core collapsing at overload, and the limited frequency response.
Also, germanium transistors sound different from silicon in these applications.
Ok, so it make specific distortion too.
Without transformer the speaker impedance is 4 ohm (see circuit diagram) can be use for deacy.
Currently I have no idea for the amp that use the transformer other than tube which sound like tube ;D
Ah yes, I did not see the speaker has its own line transformer.
4 ohm is a better match for the LT700 output transformer. I think 3 ohm is the "ideal" speaker for those but you won't find many of those new, they were once common in the days of class-A tube amplifiers. The Xicor (Mouser) ones are for 8 ohm speakers?
The transformer is included Sir,
it is mount to the speaker.
(https://i.postimg.cc/1818HwDH/Speaker.png) (https://postimg.cc/1818HwDH)
Those line transformers are often well suited for class-A tube (which you already know) although I'm sure someone has done it with class-A transistor drive.
If 3 of the transformer taps have equal winding turns between them, it may be possible to use with the Deacy class-B push-pull scheme. The diagram suggests that the 3-watt tap is between the 1.5 and 6-watt taps. So the 3-watt would be the centre tap connection to -9v in the Deacy and you don't use the 0 tap. You can confirm this by measuring the resistance between the taps. If we know these resistances someone might be able to estimate impedance and if it's suitable for the Deacy. Resistance too small might damage the transistors or too high give less power than it should.
I think the LT700 in the scheme has about 30 ohm DC resistance between the taps.
A few days ago I opened an old Philips radio recorder with a TDAxxxx chip and connected the guitar to the mag head input @ pcb.
Set it to Tape and pressed Play ... No Brian May ... but Norman Greenbaum :icon_lol:
mac
Quote from: anotherjim on June 06, 2022, 10:32:46 AM...3-watt would be the centre tap.....
No. 6W is the center-tap for the 1.5W winding.
Quote from: PRR on June 06, 2022, 03:31:51 PM
Quote from: anotherjim on June 06, 2022, 10:32:46 AM...3-watt would be the centre tap.....
No. 6W is the center-tap for the 1.5W winding.
Yes Sir Paul, 6:4.5 I think.
@Sir Jim, what I mean is the speaker may be can use for deacy amp, the transformer could be for another class A amp.
Quote from: anotherjim on June 06, 2022, 10:32:46 AM
Those line transformers are often well suited for class-A tube (which you already know) although I'm sure someone has done it with class-A transistor drive.
For tubes I have never made it, in theory from a book for class A, I've read it with transistor, in practice I haven't.
this attracts me because once made it in the form of a radio kit, like this HX108-2 7 Tube Radio Electronic DIY Kit, only locally made.
https://www.amazon.com/dp/B08C7WB8G7?ref_=cm_sw_r_cp_ud_dp_HV8DSE4TTFFXYD598A23 (https://www.amazon.com/dp/B08C7WB8G7?ref_=cm_sw_r_cp_ud_dp_HV8DSE4TTFFXYD598A23)
https://leap.tardate.com/radio/am/hx108-2/ (https://leap.tardate.com/radio/am/hx108-2/) another info in detail.
Quote from: PRR on June 06, 2022, 03:31:51 PM
Quote from: anotherjim on June 06, 2022, 10:32:46 AM...3-watt would be the centre tap.....
No. 6W is the center-tap for the 1.5W winding.
Don't you need fewer turns to get power into the thing with a low voltage amp? I can see the 6W looks like half the total winding.
Quote from: anotherjim on June 06, 2022, 04:54:07 PM
Don't you need fewer turns to get power into the thing with a low voltage amp? I can see the 6W looks like half the total winding.
This system these transformers are really made for is called "constant voltage". Often "70V". Does that help? Or do we need the chalkboard and a discussion of volts and watts?
from ref2
T2 (Output) Primary 140 ohm, Secondary 35 ohm
SP1 Speaker 3" x 5.5" PM 30-40 ohm
from ref5
T1 (Driver) Primary 2, Secondary 1
(https://i.postimg.cc/68BDn9Y3/ITOTSP.png) (https://postimg.cc/68BDn9Y3)
Quote from: zbt on June 07, 2022, 02:55:32 AM
from ref2
T2 (Output) Primary 140 ohm, Secondary 35 ohm
SP1 Speaker 3" x 5.5" PM 30-40 ohm
So the Deacy amp has an output impedance of 35 ohm, and what is the impedance of the woofer/tweeter combination in the original Deacy?
15 ohm, Elac https://yonderbosk.wordpress.com/vintage-elac-speakers/ (https://yonderbosk.wordpress.com/vintage-elac-speakers/)
It doesn't match, is this what's causing the distortion?
I think this plays a role in the sound of the amp. A lower speaker impedance means the amp is asked to deliver more current, so the output transformer will saturate sooner.
(https://i.postimg.cc/yWRRvFnb/deacyot.png) (https://postimg.cc/yWRRvFnb)
looking back at the schematic, for a deacy type output transformer the output signal is just to provide feedback.
If we omit feedback, than what use of primary windings, what if we place it with resistors?
I suspect that the problem is the two output transistors, maybe because the heat, make it out of sync.
Or maybe from the transformer driver windings, but I doubt it.
Here is a link to an interesting thread about this output stage on DIYaudio: https://www.diyaudio.com/community/threads/wtf-push-pull-output-stage.330460/ (https://www.diyaudio.com/community/threads/wtf-push-pull-output-stage.330460/)
Quote from: zbt on June 07, 2022, 11:56:28 PM
(https://i.postimg.cc/yWRRvFnb/deacyot.png) (https://postimg.cc/yWRRvFnb)
If we omit feedback, than what use of primary windings, what if we place it with resistors?
The AC resistance as seen by the output transistors would become (too?) low.
I wonder how many turns the PR80 OT must have.
The minimun freq of a guitar is about 80hz.
And the OT primary impedance is Zp=140CT. The secondary 35 (140/35=4 --> 2:1 turn ratio)
From Z = w.L = 2.pi.f.u.N.N.A/L
N can be estimated.
But u ?? A/L ??
mac
Quote from: mac on June 13, 2022, 01:45:18 PM
I wonder how many turns the PR80 OT must have.
Good question. Lots of formulas on the internet, but little practical information on output transformer design for transistor amps.
I found some info in an old Telefunken handbook. For a design using AC106 output transistors (a predecessor to the AC128), and a 5 ohm load, an EI42 transformer core is used. The primary has 168 windings of 0.32mm wire center tapped, the secondary 76 windings of 0.55mm wire.
The previous is for an OT with the speaker on secondary. But the PR80 has the speaker connected to taps on the primary, and the secondary is just for feedback. So I assume the secondary can be made from thin wire, there is hardly any current flowing, and then you can make the primary wire thicker. I suggest 180 windings ct with 0.5mm wire for the primary. The DC resistance of the PR80 primary winding is 2-2.5-ct-2.5-2 , assuming the same wire for the whole primary this tells us where the taps should be: 40-50-ct-50-40.
For the secondary, the impedance ratio is 140:35, or 4:1, so the turns ratio is 2:1. So I suggest 180/2= 90 windings of 0.1mm wire.
To be clear, I have not tried this, just a guess as to what might work.
QuoteFor the secondary, the impedance ratio is 140:35, or 4:1, so the turns ratio is 2:1. So I suggest 180/2= 90 windings of 0.1mm wire.
To be clear, I have not tried this, just a guess as to what might work.
My first guess too, 40+50+ct+50+40 : 90
For the record,
My Crown CRC 530SW with silicon transistors, or my National RQ445 with Matsushitas GE sound pretty close to a Deacy.
Even the LT44/700 combo can sound really cool.
mac
Quote from: Clint Eastwood on June 08, 2022, 08:45:13 AM
Here is a link to an interesting thread about this output stage on DIYaudio: https://www.diyaudio.com/community/threads/wtf-push-pull-output-stage.330460/ (https://www.diyaudio.com/community/threads/wtf-push-pull-output-stage.330460/)
One push too hard and the other not? make asymmetrical sine wave?
Also notice the power is not positive ground, would it be problem if using pnp?
This transformer is now hard to find ???
Deacy factor
1. Amp
- Feedback frequency
- Mismatch output transistor
2. Speaker
- Honk 600 - 650 Hz
- We need Wolverine?
3. Cabinet
- ???
(https://i.postimg.cc/zbt6brM7/OTLH0606.png) (https://postimg.cc/zbt6brM7)
For LHM0606 transformer
Black - Red 6W 164.6
Black - Blue 3W 236.4
Black - Yellow 1.5W 338.7
Yellow - Blue 1.5W 102.8
Yellow - Red 4.5W 174.7
Red - Blue 3W 72.2
Black - Red 164.6
Yellow - Red 174.7
mismatch 10.1 ohm, is it good? Can Red be centre tap ???
(https://i.postimg.cc/K1B69Ckc/ITOT.png) (https://postimg.cc/K1B69Ckc)
(https://i.postimg.cc/HcsFkxSj/ITOTDim.png) (https://postimg.cc/HcsFkxSj)
From radio kit
IT
Primary 29.8
Secondary 21.2 CT 21.2 -> 42.2
OT
Primary 2.7 CT 2.7 -> 4.9
Secondary 1.7
You need to find out the turns ratio of the transformers to see if they would be suitable for a Deacy style amp. Connect an AC signal on one side, and measure what voltage appears on the other side.
In this thread
https://groupdiy.com/threads/deacy-amp-transformers.78997/page-2#post-1011970 (https://groupdiy.com/threads/deacy-amp-transformers.78997/page-2#post-1011970)
someone noticed that replicas have the secondary shorted. Negative feedback is removed and at the same time the gain is boosted because a previous emitter is AC bypassed fully by a big cap.
But shorting the secondary has to change things inside the core, possibly freq response...
Mac
Quote from: Clint Eastwood on July 02, 2022, 02:43:14 PM
You need to find out the turns ratio of the transformers to see if they would be suitable for a Deacy style amp. Connect an AC signal on one side, and measure what voltage appears on the other side.
using 12.69V
IT
P 12.69 S1 2.029
P 12.69 S2 2.022
S1 12.69 P 2.705
S2 12.69 P 2.600
OT
P1 12.69 S 0.939
P2 12.69 S 0.840
S 12.69 P1 0.986
S 12.69 P2 0.976
Speaker Transformer, is high voltage, as Master Paul said.
S 12.69
C 6W 0.642 85.4
C 3W 0.463 120.5
C 1.5W 0.338 168.6
1.5W 6W 0.648 83.4
1.5W 3W 1.082 48.48
3W 6W 1.454 21.20
Who needs a rare african radio when lots of old radios are out there for a few bucks? ;D
Today I bought these two for USD 3. The bigger one was on every house in my country in the 60-70s.
https://postimg.cc/gallery/4x4ZbQ3 (https://postimg.cc/gallery/4x4ZbQ3)
mac
ha ha ha ;D
just looting around from old junk radio, suddenly a weird feeling become scavenger
https://i.postimg.cc/bZLHbnft/ITOT.png
probably affected by GAS in component level
That brown has vibrant color, Nice color Nemo
hhhhhhh that fine gold, green muse goblin?
look at this shiny OC44, this BC149 Brian May used it,
no no no Jimi used BC108, well 2N5133 is the origin,
The Vibe of C828. Our beloved uA741 famous YJM308, wait 308 thats RAT.
The JRC4558 must be the holy grail
Builder beware
https://library.oapen.org/handle/20.500.12657/48282
Single Find a partner, Couple Love your partner.
so many old junk
make me wonder how can we use the IF transformer, also so many old tape, the preamp head?
that magnectic head could be use as pickup?
etc... etc...
Okay, for deacy... I think the lo fi is good for guitar.
For me is nostalgia
Quotehttps://i.postimg.cc/bZLHbnft/ITOT.png
Old, rusty audio transformers --> Fasel mojo!! :icon_lol:
mac
Bought this off Fleabay a long time ago. Would some measurements be useful?
(https://i.postimg.cc/565pQbym/20220928-192232.jpg) (https://postimg.cc/565pQbym)
(https://i.postimg.cc/phnJWt3z/20220928-192350-HDR.jpg) (https://postimg.cc/phnJWt3z)
(https://i.postimg.cc/bG5RfvVq/20220928-192402-HDR.jpg) (https://postimg.cc/bG5RfvVq)
Nice find! I am sure this would make a great deacy style amp. To measure is to know, I for one am curious what transformers are in there.
QuoteBought this off Fleabay a long time ago. Would some measurements be useful?
Naaa... just plug a Rangemaster, TS or EQ and squeeze those Matsushitas! :icon_lol:
¿?
(https://i.postimg.cc/tsNzd9NQ/Captura-de-pantalla-2022-09-29-17-10-26.png) (https://postimg.cc/tsNzd9NQ)
mac
I ran .OP simulations of the amp stage, just for fun.
Resistors values are driver and output transformers wire resistance.
Since the original have mismatched power transistors I ran two simulations keeping the ratio hfe1/hfe2 far below from unity, 0.4 in this case.
Note power dissipation, collector and speaker currents.
(https://i.postimg.cc/SRFWj23T/pr80-2.jpg) (https://postimg.cc/S2dXvsyC)
(https://i.postimg.cc/k5HN3hcd/pr80-1.jpg) (https://postimg.cc/WDMq08C9)
No transistors were overheated during the making of this simulation! :icon_lol:
mac