Hello
Thank you for the information about the board .
When I get the info from you I already did paid for the PC boards on the Ebay .
I didn't knew there are still some boards left from GB .
But I think these board will be OK to . It cost me more a bit but that is the life .
Thanks one more time .
Greetings .
Thank you for the information about the board .
When I get the info from you I already did paid for the PC boards on the Ebay .
I didn't knew there are still some boards left from GB .
But I think these board will be OK to . It cost me more a bit but that is the life .
Thanks one more time .
Greetings .
Hello
Slowly I'm getting ready with my new KSA-50 Clone .
I just don't find 2SA970BL all the rest of the parts I have .
Did someone try these board , I'd like it because separate power supply for the input , and for the output .
Of course for the output I'm not going to use 47V I think that is to high for 2pair power transistor .Max 40V that is more than enough .
For the input I will use regulated power supply .The reason I prefer these board because the separate power supply and the power transistors goes direct into the board .
I will see how will work out to me .
Some picture.
Greetings
Slowly I'm getting ready with my new KSA-50 Clone .
I just don't find 2SA970BL all the rest of the parts I have .
Did someone try these board , I'd like it because separate power supply for the input , and for the output .
Of course for the output I'm not going to use 47V I think that is to high for 2pair power transistor .Max 40V that is more than enough .
For the input I will use regulated power supply .The reason I prefer these board because the separate power supply and the power transistors goes direct into the board .
I will see how will work out to me .
Some picture.
Greetings
Attachments
BL type or GR the right transistor ???
Hello
I would like to ask for help!
Unfortunately I can't find 2SA970BL & 2SC2240BL transistors but I have GR type .
Can I use them ??
Please help me with these problem , with out the right information I afraid to use the GR type .
Thanks for your help .
Greetings
Hello
I would like to ask for help!
Unfortunately I can't find 2SA970BL & 2SC2240BL transistors but I have GR type .
Can I use them ??
Please help me with these problem , with out the right information I afraid to use the GR type .
Thanks for your help .
Greetings
Hi,
check the Vbe of each transistor @ the operating current.
At the same time measure the hFE.
Now select the transistors with the matching Vbe AND highest hFE.
the gr grade go upto 400 and the bl grade go down to 350. You may be very lucky.
The closer the matching of the LTP pairs the less the input offset currents change with temperature.
The higher the hFE the lower the input offset current.
check the Vbe of each transistor @ the operating current.
At the same time measure the hFE.
Now select the transistors with the matching Vbe AND highest hFE.
the gr grade go upto 400 and the bl grade go down to 350. You may be very lucky.
The closer the matching of the LTP pairs the less the input offset currents change with temperature.
The higher the hFE the lower the input offset current.
Hello Andrew
The VBE is the same at bot type of transistor .
The only difference I see the GR type has a bit higher hfE .
I think I can use it , some one sell on the forum BL type I wrote twice almost two weeks and no answer .
I have at home GR type I will try them .
Thanks for your help .
I did some further populating the PC boards .
I just wait from 1000uF Philips axial from UK and emitter resistors from Hong Kong .Unfortunately the normal 5W resistor it doesn't feet into the board .I will use the BOSOZ power supply to drive the font and for the high power I use normal power supply .
One more picture .
Greetings
The VBE is the same at bot type of transistor .
The only difference I see the GR type has a bit higher hfE .
I think I can use it , some one sell on the forum BL type I wrote twice almost two weeks and no answer .
I have at home GR type I will try them .
Thanks for your help .
I did some further populating the PC boards .
I just wait from 1000uF Philips axial from UK and emitter resistors from Hong Kong .Unfortunately the normal 5W resistor it doesn't feet into the board .I will use the BOSOZ power supply to drive the font and for the high power I use normal power supply .
One more picture .
Greetings
Attachments
no.gaborbela said:
You must measure your transistors to find the Vbe and hFE.
Do this at the operating current. I think the KSA50 operates @ 1.5mA on the input stage.
Then pick the best matches in NPN and also in PNP.
The gr has lower hFE than bl. But the range overlaps slightly, that's where you might be lucky.
Hi Andrew
I measured 23PC of 2SA970GR , the best I can get 345hFE out of the Gr type .
I don't know what to do it would be better I think to buy at least 20-25 pair BL type .
I invested in these amp to much , I do not want these transistor mes up the whole thing .
Ruach has BL type but unfortunately He didn't answer 2 weeks now .
I have to search on line maybe some store has them .
Greetings
I measured 23PC of 2SA970GR , the best I can get 345hFE out of the Gr type .
I don't know what to do it would be better I think to buy at least 20-25 pair BL type .
I invested in these amp to much , I do not want these transistor mes up the whole thing .
Ruach has BL type but unfortunately He didn't answer 2 weeks now .
I have to search on line maybe some store has them .
Greetings
Hello
Did someone built the KSA-50 amp using Toshiba power transistors like 2SC5200.
If yes please if you had chance to com pair with the ON semi MJL21193/94 .The MJL has low hFE unfortunately , I think to swap with Toshiba .But before I do I want to know if is worth the effort .
Any sonic differences ?
The Toshiba has higher MHz .
Thanks
Greetings
Did someone built the KSA-50 amp using Toshiba power transistors like 2SC5200.
If yes please if you had chance to com pair with the ON semi MJL21193/94 .The MJL has low hFE unfortunately , I think to swap with Toshiba .But before I do I want to know if is worth the effort .
Any sonic differences ?
The Toshiba has higher MHz .
Thanks
Greetings
I never realized the difference of the front end of the Pinkmouse and Delta Audio boards -
Jan's Delta Audio boards use 2SA970BL/2SC2240BL and the Pinkmouse boards use MPSA42/92... are these interchangeable?
Is one better than the other?
Garborella, a few of us have used the 2SA1943/2SC5200 combo on the Krell Clone. I like mine, but have never heard with any other output device...
Jan's Delta Audio boards use 2SA970BL/2SC2240BL and the Pinkmouse boards use MPSA42/92... are these interchangeable?
Is one better than the other?
Garborella, a few of us have used the 2SA1943/2SC5200 combo on the Krell Clone. I like mine, but have never heard with any other output device...
Thanks
I had the old Pinkmouse BOM and schematic .
The old uses 2SA970BL / 2SC2240BL .
I purchased my PC board on the Ebay , it has separate power supply for the front and for the high power .
That was made after the old Pinkmouse BOM .
If I knew MPSA42/92 is OK to the front I could save $40 today .
I just ordered 50 pair 2SA970BL & 2SC2240BL from USA .
Thanks anyway .Is a great help .
Greetings
I had the old Pinkmouse BOM and schematic .
The old uses 2SA970BL / 2SC2240BL .
I purchased my PC board on the Ebay , it has separate power supply for the front and for the high power .
That was made after the old Pinkmouse BOM .
If I knew MPSA42/92 is OK to the front I could save $40 today .
I just ordered 50 pair 2SA970BL & 2SC2240BL from USA .
Thanks anyway .Is a great help .
Greetings
Hi!
I finaly finished my Krell, but i have a problem. I can't adjust bias across emiter resistors. I have zero V and trimpot does not working on boat channels. DC offset was no problem to set, and I even listen to some music and sounds good, but bias adjustment doesnt working. I have Jan's boards with corrected traces, 2sc3955 for bias transistor. Any idea?
Thanks
Dean
I finaly finished my Krell, but i have a problem. I can't adjust bias across emiter resistors. I have zero V and trimpot does not working on boat channels. DC offset was no problem to set, and I even listen to some music and sounds good, but bias adjustment doesnt working. I have Jan's boards with corrected traces, 2sc3955 for bias transistor. Any idea?
Thanks
Dean