Came across some 5 years old SymAsym boardfile, which is probably still worth publishing. The schematic was already shown in this thread. Post # 54.
Is it an updated sym with excellent specs. The board was initially designed by Alex MM, and is a single-sided PCB, really great for home (DIY) etching.
This amplifier is already years in personal service and is one of my prefered DIY-amps.
The PCB is suitable and functional for a JFET or BJT diff. pair. If you apply a BJT diff. pair, then there is an optional offset adjustment arrangement on this boards.
Note: The PCB is layed-out for used a dual matched transistor LM394 input pair! The 2SK170 can be used without any modification.
Some highlights:
Low idle power dissipation, rock stable Triplet (CPF)/Compound OPS, fast voltage feedback amplifier.
Some specs:
THD(20k) : 45ppm @ 50W (BW: 80kHz)
Is it an updated sym with excellent specs. The board was initially designed by Alex MM, and is a single-sided PCB, really great for home (DIY) etching.
This amplifier is already years in personal service and is one of my prefered DIY-amps.
The PCB is suitable and functional for a JFET or BJT diff. pair. If you apply a BJT diff. pair, then there is an optional offset adjustment arrangement on this boards.
Note: The PCB is layed-out for used a dual matched transistor LM394 input pair! The 2SK170 can be used without any modification.
Some highlights:
Low idle power dissipation, rock stable Triplet (CPF)/Compound OPS, fast voltage feedback amplifier.
Some specs:
THD(20k) : 45ppm @ 50W (BW: 80kHz)
Attachments
Piersma,
1) What technique do you use to make your home etchings?
2) The green parts placing file shows a slightly better, IMHO, pcb, with larger traces.
3) How about going complete DC, with a dual FET at the input and offset trimming, and more power? I think I did see a supersym version that was like that...
1) What technique do you use to make your home etchings?
2) The green parts placing file shows a slightly better, IMHO, pcb, with larger traces.
3) How about going complete DC, with a dual FET at the input and offset trimming, and more power? I think I did see a supersym version that was like that...
Etching a PCB
hi Carlmart,
This is my etching method:
The PCB layout is printed 1:1 on paper by means of a (laser) printer or copier machine. Sunflower-seed oil is used to make the white part of the layout paper.
I use lithography to transfer the design and ammonium persulfate for etching. (PCB Etching)
The shown lay-outs are all exactly the same and original PCB files, there's no difference!
Several years ago I tried the dual matched FET 2N2912 on this board, it worked without problems. Other dual TO-78 FET's need to be tested in this particular design but probably would work also. The 2SK389 would be a very nice option, but has a different footprint.
have fun building!
hi Carlmart,
This is my etching method:
The PCB layout is printed 1:1 on paper by means of a (laser) printer or copier machine. Sunflower-seed oil is used to make the white part of the layout paper.
I use lithography to transfer the design and ammonium persulfate for etching. (PCB Etching)
The shown lay-outs are all exactly the same and original PCB files, there's no difference!
Several years ago I tried the dual matched FET 2N2912 on this board, it worked without problems. Other dual TO-78 FET's need to be tested in this particular design but probably would work also. The 2SK389 would be a very nice option, but has a different footprint.
have fun building!
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