2SA970 / 2SC2240 are obsolete.
Their SMD equivalents 2SA1312 / 2SC3324 are not.
For a public project, one should use active components as much as possible.
Of course one can also try BC327 / 337.
But they are not as low noise.
Cheers,
Patrick
Their SMD equivalents 2SA1312 / 2SC3324 are not.
For a public project, one should use active components as much as possible.
Of course one can also try BC327 / 337.
But they are not as low noise.
Cheers,
Patrick
HI Patrick, thank you for sharing your master work.
However, I can't read correctly the files, the traces don't match with the photos of the proto build. Could you kindly check? Many thanks
Guido
Guido - I had a few boards made from Patricks Gerbers and they are fine, I can spare you a couple if just want a quick look. Will send a PM.
Hi,
Is it possible to use 2SC5171/2SA1930 as output device without any modification?
Thanks.
Regards,
Tat
Is it possible to use 2SC5171/2SA1930 as output device without any modification?
Thanks.
Regards,
Tat
Note also that the hfe of those Toshiba devices begins to drop above 300mA.
Whereas the Sankens can go much higher.
So in addition to availability, the Sankens are also better devices.
Patrick
Whereas the Sankens can go much higher.
So in addition to availability, the Sankens are also better devices.
Patrick
Patrick please excuse another simple question -
Regarding the R1/R2, R3/R4 resistor arrays for tuning the offset and bias, I am confused as to how to set the initial default value for each array if there is one. For instance should R1 be 2 x 3.3K in parallel... I understand we are splitting this to allow for optional 200uF decoupling cap.
Can I ask what values you began with on your prototype?
Edit... sorry I just saw your assembled boards in post #80 so I have an idea now.
Regarding the R1/R2, R3/R4 resistor arrays for tuning the offset and bias, I am confused as to how to set the initial default value for each array if there is one. For instance should R1 be 2 x 3.3K in parallel... I understand we are splitting this to allow for optional 200uF decoupling cap.
Can I ask what values you began with on your prototype?
Edit... sorry I just saw your assembled boards in post #80 so I have an idea now.
Last edited:
The default values of the said resistors were given in the PDF article.
e.g. R1 is 3.3k // 3.6k.
So I do not quite understand why it is not clear ??
Patrick
e.g. R1 is 3.3k // 3.6k.
So I do not quite understand why it is not clear ??
Patrick
It's ok Patrick, once I saw your built boards it became obviously clear.
Initially the PDF was not clear to an idiot like me, I wasn't sure if... 2+2 R1,R3 3.3K//3.6K meant two of each resistor on each rail. I see now that each group has one spare pad for a 1M if needed.
Maybe it would be better to read:
R1,R3 - Susumu 0805 1x 3.3K // 1x 3.6K and - R2,R4 -2x 0805 20K // 1x 18K...
Just for idiots like me. It's fine really.
Initially the PDF was not clear to an idiot like me, I wasn't sure if... 2+2 R1,R3 3.3K//3.6K meant two of each resistor on each rail. I see now that each group has one spare pad for a 1M if needed.
Maybe it would be better to read:
R1,R3 - Susumu 0805 1x 3.3K // 1x 3.6K and - R2,R4 -2x 0805 20K // 1x 18K...
Just for idiots like me. It's fine really.
I forgot to attach the Spice file of the modified version.
You can play with it to see what effect you get when you change which value, etc.
It is not 100% reality, but it is close.
Patrick
.
You can play with it to see what effect you get when you change which value, etc.
It is not 100% reality, but it is close.
Patrick
.
Hi Patrick. Are these suitable for the Q1/Q2 devices for the original JLH circuit?
KSC1845FTA ON Semiconductor / Fairchild | Mouser Finland
KSA992FTA ON Semiconductor / Fairchild | Mouser Finland
Hfe range with these is according to datasheet 300-600 instead of the original BOM's E-series 400-800.
KSC1845FTA ON Semiconductor / Fairchild | Mouser Finland
KSA992FTA ON Semiconductor / Fairchild | Mouser Finland
Hfe range with these is according to datasheet 300-600 instead of the original BOM's E-series 400-800.
Yes, in principle.
The problem I have with the On Semi devices are :
a) hfe of N & P devices are quite different.
b) hfe is not quite constant with current.
Function they will.
Whether distortion the same is another question.
But then a bit more 2nd harmonics is also not dramatic.
If you have them, then give them a try.
Patrick
The problem I have with the On Semi devices are :
a) hfe of N & P devices are quite different.
b) hfe is not quite constant with current.
Function they will.
Whether distortion the same is another question.
But then a bit more 2nd harmonics is also not dramatic.
If you have them, then give them a try.
Patrick
Ok. I don’t have the parts yet as I’m preparing an order from Mouser and they seem to have only the devices I linked in stock. Can you please point me to a source that has suitable parts in stock? Digi-key seemed to have the same devices as Mouser.
You can just order a few from Mouser first and try them, just to make it work.
Then search for Toshiba 2SA970BL & 2SC2240 BL.
(Note that there are now Indian CDIL parts with the same number, so has to be Tos.)
GR will also do, but of course BL is better.
hfe is much more linear over a wider range.
Just a bit difficult to get, but still available and not expensive.
Patrick
Then search for Toshiba 2SA970BL & 2SC2240 BL.
(Note that there are now Indian CDIL parts with the same number, so has to be Tos.)
GR will also do, but of course BL is better.
hfe is much more linear over a wider range.
Just a bit difficult to get, but still available and not expensive.
Patrick
BTW You can of course also use 2SC3324 7 2SA1312 if you can live with the heat.
Bias is about 4mA.
Patrick
Bias is about 4mA.
Patrick