Hi Carlos,
Thank you so much for the nice input you have shared. it will boost up my knowledge in amplifier. I will post another querry afterwards if I could have some troubles in making this amp.
My email add: bernie_a_fernandez@yahoo.com
Regards to all,
bernhix
Thank you so much for the nice input you have shared. it will boost up my knowledge in amplifier. I will post another querry afterwards if I could have some troubles in making this amp.
My email add: bernie_a_fernandez@yahoo.com
Regards to all,
bernhix
I have a printed version made in June 2005 that is very nice
In near future i will publish.
It is a GEM version, by Graham, using transistors in the positive rail, and those are for the class A amplifier...they are complementary.
This is something less good in audio quality, but better to construct compared with the enormous Choque proposed by the last diagram published.
Do not tell the people...our secret...but Graham will not feel happy as i will show some schematic that was superated by his last published version...well, this may produce good results..he may enter to defend his design, not happy with me..... but all forum may have his valuable presence...i will loose his respect and friendship...but you all will have Graham again...good business in my point of view.
I cannot publish immediatelly as my Scanner supply is damaged.... and i have only a single printed page about it....i have not a computer image file, a digital data about that schematic.
Near future i will be back here to publish.
regards,
Carlos
In near future i will publish.
It is a GEM version, by Graham, using transistors in the positive rail, and those are for the class A amplifier...they are complementary.
This is something less good in audio quality, but better to construct compared with the enormous Choque proposed by the last diagram published.
Do not tell the people...our secret...but Graham will not feel happy as i will show some schematic that was superated by his last published version...well, this may produce good results..he may enter to defend his design, not happy with me..... but all forum may have his valuable presence...i will loose his respect and friendship...but you all will have Graham again...good business in my point of view.
I cannot publish immediatelly as my Scanner supply is damaged.... and i have only a single printed page about it....i have not a computer image file, a digital data about that schematic.
Near future i will be back here to publish.
regards,
Carlos
I will try another GEM model...but i have 4 in the strip to be made
I have started with a fast board...the awfull jumpers will go downwards de board...also the lines draw over the board are only a reference to assemble...they will be cleaned when finished.
Here is the board to be made...will delay a week or more, as i have others amplifiers to construct and listen.
regards,
Carlos
I have started with a fast board...the awfull jumpers will go downwards de board...also the lines draw over the board are only a reference to assemble...they will be cleaned when finished.
Here is the board to be made...will delay a week or more, as i have others amplifiers to construct and listen.
regards,
Carlos
Attachments
Normally i do not use layout or something alike
Watching the schematic i go drawing over the board....and them the component holes are opened.... finally, watching the over diagram the real copper lines are traced with a permanent pen under the board...referenced using the sketch and the component holes.
Finally to the acid...this waste not more than one hour...and more 2 hours to assemble, adjust and listen.
The acid i use is concentrated...it is heated in advance to the use and it is shacked during the corrosion.
The hole you see is for the bias transistor, to touch the heatsink without long wiring.
The Voltage amplifier, drivers and AB output are around the board, soldered over the board....the extra class A output is connected using 3 inches wiring.
regards,
Carlos
Watching the schematic i go drawing over the board....and them the component holes are opened.... finally, watching the over diagram the real copper lines are traced with a permanent pen under the board...referenced using the sketch and the component holes.
Finally to the acid...this waste not more than one hour...and more 2 hours to assemble, adjust and listen.
The acid i use is concentrated...it is heated in advance to the use and it is shacked during the corrosion.
The hole you see is for the bias transistor, to touch the heatsink without long wiring.
The Voltage amplifier, drivers and AB output are around the board, soldered over the board....the extra class A output is connected using 3 inches wiring.
regards,
Carlos
Attachments
Imagine the pcboard as made with transparent glass.
This way, i am showing you the parts, and at same time the copper lines..... board made transparent to easy understanding.
The ground is the line that has 7K8 resistor (8K2) conected to first transistor base.
Upper line is positive and lower line is negative.
The amplifier work in class A, so the current must be ajusted to 1.5 amperes...if not possible, go reducing to adequate to your supply, and checking the base to emitter voltages, that may be around 600 milivolts.
I do not remember if i constructed this one...maybe yes, maybe not.
Will be more safe to include a capacitor....silver mica or ceramic, from base to colector, mounted near the voltage amplifier transistor...the BD139.
Drivers can be also BD139 and BD140.
Also you can use 2N3055 or TIP3055....in the reality.... the NPN you find will work there.
Of course better transistors may work better..this amplifier is not the last model from Graham...the opposite, it is very old, and has a lot of room to modifications and improvements.
It will give you the chance to make your own unit...and to have a lot of fun.
regards and good luck
Carlos
This way, i am showing you the parts, and at same time the copper lines..... board made transparent to easy understanding.
The ground is the line that has 7K8 resistor (8K2) conected to first transistor base.
Upper line is positive and lower line is negative.
The amplifier work in class A, so the current must be ajusted to 1.5 amperes...if not possible, go reducing to adequate to your supply, and checking the base to emitter voltages, that may be around 600 milivolts.
I do not remember if i constructed this one...maybe yes, maybe not.
Will be more safe to include a capacitor....silver mica or ceramic, from base to colector, mounted near the voltage amplifier transistor...the BD139.
Drivers can be also BD139 and BD140.
Also you can use 2N3055 or TIP3055....in the reality.... the NPN you find will work there.
Of course better transistors may work better..this amplifier is not the last model from Graham...the opposite, it is very old, and has a lot of room to modifications and improvements.
It will give you the chance to make your own unit...and to have a lot of fun.
regards and good luck
Carlos
Attachments
It is wonderfull to me, to perceive that you still apreciate me
Also after that silence...not only because of me, but also because you are too much busy selling Aksas world wide.
Long life to Aksa.
Beautifull amplifier.... wonderfull sonics!
I am still an Aksa lover.... i will always apreciate bootstrapped designs...in special your Life Force.
regards,
Carlos
Also after that silence...not only because of me, but also because you are too much busy selling Aksas world wide.
Long life to Aksa.
Beautifull amplifier.... wonderfull sonics!
I am still an Aksa lover.... i will always apreciate bootstrapped designs...in special your Life Force.
regards,
Carlos
I made some work to Mod-evil, and also to all young DIY.
I cannot help, or teach, experienced people.
All the things i use to do here, is dedicated to the beginners, so, everything i will tell you, experienced guys, are too much obvious and can produce bad feelings inside your mind.
No!...i have any intention to teach electronics to old experienced Diyers.... i cannot do that, i have not theory enougth to that.
Only practice...experience..long years burning fingers....46 years to be more exactly.....yes!...i am proud of that!
This circuit..bootstrapped, is a magnificent circuit...produces a very nice sonics, and despite old (seventies) are still used .... included in many Chip amplifiers and factories are still doing them.
It is special interesting because is very simple and offer you room to researches.... many modifications can be done, and the result can be very different, depending where you tweak and how you do that.
In our DIY community there are some guys very expecialized in those designs and i can guarantee that they could make top performance amplifiers...unbeatable in sonics.... very nice, even showing you some measured distortions.....nice distortions if you want to know.
Graham is researching and trying to make it better and better...and this started more than 30 years ago.
Depending the mods you can do, this amplifier can show you wonderfull sonics....and can also be very bad in noise...strange in dinamics...and harshing in treble...but if you discover those secrets you will have an astounding sonics that will turn you very bad to your diy partners...as you can invite everyone for A to B comparison...and relax...you will win them, at least in sound stage and treble.
Here is another board lay out .... watching over a transparent board...this is the image's position...observing from up... looking the components...and imagine the board as made with transparent glass...so..you will be watching copper line.
regards,
Carlos
I cannot help, or teach, experienced people.
All the things i use to do here, is dedicated to the beginners, so, everything i will tell you, experienced guys, are too much obvious and can produce bad feelings inside your mind.
No!...i have any intention to teach electronics to old experienced Diyers.... i cannot do that, i have not theory enougth to that.
Only practice...experience..long years burning fingers....46 years to be more exactly.....yes!...i am proud of that!
This circuit..bootstrapped, is a magnificent circuit...produces a very nice sonics, and despite old (seventies) are still used .... included in many Chip amplifiers and factories are still doing them.
It is special interesting because is very simple and offer you room to researches.... many modifications can be done, and the result can be very different, depending where you tweak and how you do that.
In our DIY community there are some guys very expecialized in those designs and i can guarantee that they could make top performance amplifiers...unbeatable in sonics.... very nice, even showing you some measured distortions.....nice distortions if you want to know.
Graham is researching and trying to make it better and better...and this started more than 30 years ago.
Depending the mods you can do, this amplifier can show you wonderfull sonics....and can also be very bad in noise...strange in dinamics...and harshing in treble...but if you discover those secrets you will have an astounding sonics that will turn you very bad to your diy partners...as you can invite everyone for A to B comparison...and relax...you will win them, at least in sound stage and treble.
Here is another board lay out .... watching over a transparent board...this is the image's position...observing from up... looking the components...and imagine the board as made with transparent glass...so..you will be watching copper line.
regards,
Carlos
Attachments
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