Thanks ,waiting for this.Yes, I will post a circuit up tomorrow.
just before......fire!
Poor man's sx-amplifier,or sx-ampl.with what i have
i will never use lead free solder again
BTW it's on my plan testing this with one pair out biased in class A
Poor man's sx-amplifier,or sx-ampl.with what i have
i will never use lead free solder again
BTW it's on my plan testing this with one pair out biased in class A
Attachments
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Thanks pinnocchio.Nice job thimios! Hope you like the sound of it
Ciao!
Do
Here is the completed channel.
Attachments
Thanks Bonsai ,i believe a small modification at the bias circuit is necessary .Very nice! I like the Sankens! They will work fine in this circuit.
It can't go down from 660mV from one emitter to other emitter(output transistors).
PS just now i see that the recommended current is 1.5A
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Yes, I will post a circuit up tomorrow.
I will post it up later this week. Too busy at the moment!
Ok,never mind.I will post it up later this week. Too busy at the moment!
We can wait
sx
Today is a listening test day.
Power supply: +/-20V D.C
33000UF/Rail
EI transformer
Biased at 1.5A
One pair OUT.
Offset=0 mV absolutely stable.
From this first test it is clear,this is a very good sounding amplifier,deep bass,clear high .
Congratulations Bonsai good job!
PS measurement test some days later.
Thimios.
Today is a listening test day.
Power supply: +/-20V D.C
33000UF/Rail
EI transformer
Biased at 1.5A
One pair OUT.
Offset=0 mV absolutely stable.
From this first test it is clear,this is a very good sounding amplifier,deep bass,clear high .
Congratulations Bonsai good job!
PS measurement test some days later.
Thimios.
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Good luck!my first move. the poor boy sx boards
Here is the single sided sx-Amp (15 Watt Class A CFA) PCB layout in Gerber format I promised a few days ago.
I have not built this version (only the THP version)
So, please feel free to take a look.
The circuit is the same as for the one in the write-up on my website except that I have replaced C2 with a through hole electrolytic device and J2 is removed. Further, all the semiconductors are now through hole.
The overlay and circuit diagram are attached as .jpg
NOTE: THIS LAYOUT INCORPORATES THE UPDATED RESISTOR VALUES FOR R28, R29 AND R36 AND R37.
I don't know how to turn this into a .pdf file - anyone got any ideas? This will mean people can etch their own boards.
The write on this amplifier is on my website - here is a link for your convenience: Ovation sx-Amplifier: A 15 W class A Amplifier
Happy building!
hi mr bonsai. i get confuse about cap 2 10uf around tr 3.bc547. its different on single side and double layer schematic. why? regards
That's C2 - it simply decouples Q3 collector to emitter so that at HF its still a low impedance.
Q3 is the bias generator.
Note the sx-Amplifier bias generator doe not work like an ordinary Vbe multiplier - its actually measuring the voltage across the out devices emitter degen resistors and then controlling the base voltage across the output devices.
Q3 is the bias generator.
Note the sx-Amplifier bias generator doe not work like an ordinary Vbe multiplier - its actually measuring the voltage across the out devices emitter degen resistors and then controlling the base voltage across the output devices.
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