Hi, everybody!
First of all, excuse me for my poor English. I´m trying to improve.
I would like to built an amplifier that sound fine and are easy to do. So the Blameless from D. Self looks to me exactly what I´m looking for. If anyone know another circuit, please, send me a message.
My doubt is about the transistors that I would like to use. Lets start:
I´m using the schematic at figure 33 of the article:
http://www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
And I have some transistors. Could I use:
TR7, TR9 - 2sc3281, 2sa1302
TR6, TR8 - 2sc4793, 2sa1837
TR13 - 2sc4793 (can I use the 2sc3790???)
TR1, TR5 - 2sa1376 (insted of bc 560)
TR4, TR12 - 2sc3478 (insted of bc 550)
TR2, TR3 e TR10, TR11 - 2sc3381 - 2sa1349 (2 transistor in 1 capsule)
Do you think it will work fine? Is it true that the bass is weak, as Carlos destroyer X said in his topic about DX Blameless? Or Carlos are made a mistake???
Anyone can help me with the pcb layout? I´m trying to do, but I´m having difficulties... If anyone could send me a layout, just to help me to do a new one...
Other information:
The power suply is +32,4V / -32,8V DC, with 45000 uF. Its sufficient simetry?
I´ve built the loudspeakers, a copy from a brazilian diyer (a clone of Sublimes), and it´s sound very nice.
And I would like to use a fine amp to drive this loudspeaker.
Thanks a lot. And marry christmas!
Ricardo (Ricks)
First of all, excuse me for my poor English. I´m trying to improve.
I would like to built an amplifier that sound fine and are easy to do. So the Blameless from D. Self looks to me exactly what I´m looking for. If anyone know another circuit, please, send me a message.
My doubt is about the transistors that I would like to use. Lets start:
I´m using the schematic at figure 33 of the article:
http://www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
And I have some transistors. Could I use:
TR7, TR9 - 2sc3281, 2sa1302
TR6, TR8 - 2sc4793, 2sa1837
TR13 - 2sc4793 (can I use the 2sc3790???)
TR1, TR5 - 2sa1376 (insted of bc 560)
TR4, TR12 - 2sc3478 (insted of bc 550)
TR2, TR3 e TR10, TR11 - 2sc3381 - 2sa1349 (2 transistor in 1 capsule)
Do you think it will work fine? Is it true that the bass is weak, as Carlos destroyer X said in his topic about DX Blameless? Or Carlos are made a mistake???
Anyone can help me with the pcb layout? I´m trying to do, but I´m having difficulties... If anyone could send me a layout, just to help me to do a new one...
Other information:
The power suply is +32,4V / -32,8V DC, with 45000 uF. Its sufficient simetry?
I´ve built the loudspeakers, a copy from a brazilian diyer (a clone of Sublimes), and it´s sound very nice.
An externally hosted image should be here but it was not working when we last tested it.
And I would like to use a fine amp to drive this loudspeaker.
Thanks a lot. And marry christmas!
Ricardo (Ricks)
Thank you Jaycee
At least you trust me.... my dear Brazilian friend seems that do not trust very much. Congratulations, this is the spirit, do not trust people, build yourself, listen, compare, and obtain your own conclusions about.
Tem muita gente achando muita coisa sem saber de nada, só achismo... there are so too many folks that imagine a lot of things, but they really do not know.... there's only one way to know, to build, to compare and to analise....other things are opinions, and the value of that is none.
Now a days i an trying Blameless Designs, and they are driving me crazy because oscilations. also they could not survive the endurance test with 3,5 ohms plus 2,2uf in paralell.
Sometimes we fell the bass weak because of treble reproduction excelence.
I have solved the bass problem, now trying to make it more stable.
You do not need to ask my forum frienfs if i have made a mistake...i can answer you... i do mistakes all time long and everyday, because i am always doing things, and thanks lord, learning everyday because my own errors.
Ahahaha!, you talk alike me, indian way...me good!...marry christmas...alguém casou com o natal.
Fui! (bye!)
Carlos
At least you trust me.... my dear Brazilian friend seems that do not trust very much. Congratulations, this is the spirit, do not trust people, build yourself, listen, compare, and obtain your own conclusions about.
Tem muita gente achando muita coisa sem saber de nada, só achismo... there are so too many folks that imagine a lot of things, but they really do not know.... there's only one way to know, to build, to compare and to analise....other things are opinions, and the value of that is none.
Now a days i an trying Blameless Designs, and they are driving me crazy because oscilations. also they could not survive the endurance test with 3,5 ohms plus 2,2uf in paralell.
Sometimes we fell the bass weak because of treble reproduction excelence.
I have solved the bass problem, now trying to make it more stable.
You do not need to ask my forum frienfs if i have made a mistake...i can answer you... i do mistakes all time long and everyday, because i am always doing things, and thanks lord, learning everyday because my own errors.
Ahahaha!, you talk alike me, indian way...me good!...marry christmas...alguém casou com o natal.
Fui! (bye!)
Carlos
Last edited:
Hi, everybody
Carlos, whats the problem if I´m asking if you made a mistake???
By the way, why don´t you aswer my questions?
First:
Can I use:
TR1, TR5 - 2sa1376 (insted of bc 560) ?
TR4, TR12 - 2sc3478 (insted of bc 550) ?
are they (2sa1376, 2sc3478) better than BC550/560?
Second:
Why the original circuit has oscilations? If I make a copy of the original, it won´t work fine???
Last question:
"Sometimes we fell the bass weak because of treble reproduction excelence" It´s not a good answer to the bass weak. Did you measure? Am I need a subwoofer? The original amplifier don´t have a flat response curve?
I´m just trying to built an amplifier that sound better than my Quasar 7070. I´m not trying to built the best amp of the world. As I said, this circuit looks exactly what I´m looking for.
Thanks a lot. And happy new year.
Ricks
Carlos, whats the problem if I´m asking if you made a mistake???
By the way, why don´t you aswer my questions?
First:
Can I use:
TR1, TR5 - 2sa1376 (insted of bc 560) ?
TR4, TR12 - 2sc3478 (insted of bc 550) ?
are they (2sa1376, 2sc3478) better than BC550/560?
Second:
Why the original circuit has oscilations? If I make a copy of the original, it won´t work fine???
Last question:
"Sometimes we fell the bass weak because of treble reproduction excelence" It´s not a good answer to the bass weak. Did you measure? Am I need a subwoofer? The original amplifier don´t have a flat response curve?
I´m just trying to built an amplifier that sound better than my Quasar 7070. I´m not trying to built the best amp of the world. As I said, this circuit looks exactly what I´m looking for.
Thanks a lot. And happy new year.
Ricks
I have built Dougs blameles Class B when it first appeared in Electronics/Wireless World using the official PCB's. It's good amp, technically very good, but.... sonically you can do better...
As Carlos says, you have to listen to different amps and topologies to appreciate where the differences are.
What I like you may not
As Carlos says, you have to listen to different amps and topologies to appreciate where the differences are.
What I like you may not
Carlos, i trust your ears and experience I have not built your amps but have seen the development of them, and the schematics.. and they look like good solid designs.
Personally I prefer the "differential VAS" type amps as used by ostripper in some of his Frugalamps, although right now I am looking at the Tom Holman "APT" topology.
I have not built your amps but have seen the development of them, and the schematics.. and they look like good solid designs.Personally I prefer the "differential VAS" type amps as used by ostripper in some of his Frugalamps, although right now I am looking at the Tom Holman "APT" topology.
Ricardo, write to me, i have made audio answering you.
carlos.eugenio1951@yahoo.com
I will know your email adress after receive your message, then the MP3, 25 minutes audio will go to your inbox.
regards,
Carlos
carlos.eugenio1951@yahoo.com
I will know your email adress after receive your message, then the MP3, 25 minutes audio will go to your inbox.
regards,
Carlos
I have built Dougs blameles Class B when it first appeared in Electronics/Wireless World using the official PCB's. It's good amp, technically very good, but.... sonically you can do better...
As Carlos says, you have to listen to different amps and topologies to appreciate where the differences are.
What I like you may not
Thank you for the answer. I will try to built the Blameless, and I´m almost sure that will be better than the amplifier I have.
Regards
Ricks
The article in EE and the "final" version and notes with the official PCB's has a 15pf cap in series with a 330 ohm connected across the 10k feedback resistor R8.
The emmiter resistors on the outputs are 0.22 ohm.
The original transistors are 2N5401 and 2N5551 for all small signal.
MJE340 and MJE350 for the VAS stage, TR4 and 5 on your fig 33
Outputs MJ4502 and MJ802
These were the types I used too... all built exactly to Dougs spec in the original final version.
The emmiter resistors on the outputs are 0.22 ohm.
The original transistors are 2N5401 and 2N5551 for all small signal.
MJE340 and MJE350 for the VAS stage, TR4 and 5 on your fig 33
Outputs MJ4502 and MJ802
These were the types I used too... all built exactly to Dougs spec in the original final version.
maybe this would help
Audio power amplifier design handbook - Knihy Google
Audio power amplifier design handbook - Knihy Google
Code:
http://books.google.cz/books?id=BRQZppvawWwC&printsec=frontcover&dq=Amplifier+handbook&cd=1the handbook shows four complete ClassAB (=Self's ClassB) amplifier schematics.
Two are CFP, one is quasi and one is EF output stage.
The EF shows the feedback modification, the later trimodal and load invariant versions revert to the plain feedback.
The 20W ClassA (EF output) also shows the modified feedback.
Two are CFP, one is quasi and one is EF output stage.
The EF shows the feedback modification, the later trimodal and load invariant versions revert to the plain feedback.
The 20W ClassA (EF output) also shows the modified feedback.
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