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Looking nice indeed.
It's a good moment when the chit chat moves on from design quibles to getting the thing built, debugged and playing.
It's a good moment when the chit chat moves on from design quibles to getting the thing built, debugged and playing.
this moment is very special..just let it not oscillate when its finished...
here are some other pictures. i havent placed all the parts yet.some parts are missing...
by the way are there any better sounding small signal transistors to place insteed of bc546-56 ??
here are some other pictures. i havent placed all the parts yet.some parts are missing...
by the way are there any better sounding small signal transistors to place insteed of bc546-56 ??
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I've only used 2N5401/2N5551's which I liked the sound of but I can't compare them to the one's you have chosen - I'm pretty sure they'll sound great.
Don't forget to clean the flux off your boards using acetone or something once you've finished soldering them.
For me, the easiest way to spot oscillations was a 'warm' zobel resistor.
Don't forget to clean the flux off your boards using acetone or something once you've finished soldering them.
For me, the easiest way to spot oscillations was a 'warm' zobel resistor.
...replacement for BC546 -556
Nice work , you can use 2SC2240 / 2sa970 ,are good too.
Regards Alex. 🙂
Nice work , you can use 2SC2240 / 2sa970 ,are good too.
Regards Alex. 🙂
for vas and drivers i have read that its good to use very fast transistors with high hfe and low capacitance between junctions
for drivers and vas i am planning to use 2sd669a -2sb649a and for vbe multiplier bd139.
2sd669a -2sb649a have the same pin configuration with bd139-140 so its ok on the board.
do you have any other suggestions about good sounding transistors for these stages?
for drivers and vas i am planning to use 2sd669a -2sb649a and for vbe multiplier bd139.
2sd669a -2sb649a have the same pin configuration with bd139-140 so its ok on the board.
do you have any other suggestions about good sounding transistors for these stages?
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2sb649/d669 have typical driver parameters. Cob~27pF to 30pF, Id~1.5A to 2A
You should use something more like 2sa1360/c3423, or 1370, or 1371, or 1380, or 1381, or 1403, 1404, or 1405, or 1406, or 1407 (possibly the best from this list) as a VAS
There are dozens of others that make suitable VAS and Pre-Drivers.
As far as I have seen, all To126 devices have the same pin out and this is the reverse of the To220 pin out.
You should use something more like 2sa1360/c3423, or 1370, or 1371, or 1380, or 1381, or 1403, 1404, or 1405, or 1406, or 1407 (possibly the best from this list) as a VAS
There are dozens of others that make suitable VAS and Pre-Drivers.
As far as I have seen, all To126 devices have the same pin out and this is the reverse of the To220 pin out.
i will try to find one of 1404,1405 ,1406 ,1407 for VAS.
can i use any other transistor for current source of VAS or its better to use the complemetary of the one i am using for VAS?
can i use any other transistor for current source of VAS or its better to use the complemetary of the one i am using for VAS?
, have you seen the schematic? whats your opinion about it?are there any component values that should be changed?
http://www.diyaudio.com/forums/attachments/solid-state/171873d1274189196-sziklai-power-amplifier-new-sziklai-final-3.pdf
How can i see the phase and gain margins using multisim ?the expression i use for open loop gain is vout/(v(+) - v(-)) but which expression i use for the loop gain?
I made the amplifier and listened to it at full power .it sounds nice.there was no matter of instability ,no strange overheating.
But all these have to be confirmed by an oscilloscope which i dont have.
If anyone wants to build it ,please use the pcb below that Alex mm sent me.
previous pcbs had something missing and Alex mm corrected it.
this is the correct one.
transistors that i used were: 2sd669a-2sb649a instead of bd139-bd140
2sc5200-2sa1943 for output
bc546-bc556 for input
2n5551 as the small tranistor before the VAS (PINS REVERSED TO BC546)
my best regards to Alex mm who designed the pcb ,and to all of you that helped me with the schematic .
But all these have to be confirmed by an oscilloscope which i dont have.
If anyone wants to build it ,please use the pcb below that Alex mm sent me.
previous pcbs had something missing and Alex mm corrected it.
this is the correct one.
transistors that i used were: 2sd669a-2sb649a instead of bd139-bd140
2sc5200-2sa1943 for output
bc546-bc556 for input
2n5551 as the small tranistor before the VAS (PINS REVERSED TO BC546)
my best regards to Alex mm who designed the pcb ,and to all of you that helped me with the schematic .
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