maybe the use of BD139-140 is already sufficient as vas transistor, you may try to simulate with these
scope view "after coil" is of no value.
scope before coil with Rload connected.
Check for various Rload and C//Rload.
scope before coil with Rload connected.
Check for various Rload and C//Rload.
Hi everyone,
I have made 2 PCBs of AX11 but MPSA13,BC639 and BC640 is not available here. Any substitute for these transistors?😕😕😕
I have made 2 PCBs of AX11 but MPSA13,BC639 and BC640 is not available here. Any substitute for these transistors?😕😕😕
Just my 2 cents:
How about using the BD139/140 in place of the BC639/640?
A BD139 instead of the MPSA13 would work fine as a thermal sensor, the TO-126 case is so much easier to put on the heatsink than the TO-92.
The pcb has to be changed accordingly, but that's not so difficult.
As long as the rails aren't raised too high, then the BD139/140 do fine there and those may be easier to find. They are already usable as drivers.
btw: if there is no way to get certain transistors, such as those BC639/640 in some countries, perhaps someone else can get them and re-ship them. I will be making use of a few of those real soon, so I'll be on the hunt for them too. I know I will find them. It may not be right away, but if it can wait until then, I would consider getting a bigger quantity and re-ship to those who can't get them, if they don't get intercepted for some obscure reason...
There is many substitutions for this transistors but I don't know what is available in your place.
2SA1013/2SC2383 can be use instead BC639/BC640 and it's better than BC I use it in HV23
How many are in need of the BC639/640 and who can't get them?
This can get complicated, but as long as we're not dealing with too many parts, we may be able to arrange a group buy. The shipping costs have to be considered, plus customs and associated costs, but on just transistors, it may not be too much.
It might be possible to mail them in a way that doesn't attract attention, between cardboard, perhaps with some noise making type of greeting card, that already has electronics in it.... Whatever.
This can get complicated, but as long as we're not dealing with too many parts, we may be able to arrange a group buy. The shipping costs have to be considered, plus customs and associated costs, but on just transistors, it may not be too much.
It might be possible to mail them in a way that doesn't attract attention, between cardboard, perhaps with some noise making type of greeting card, that already has electronics in it.... Whatever.
NICE WORK
THANK YOU MR MILE GIVE ME A LOT OF SCIENCE.
GREETINGS TO ALL, THIS IS MY FIRST POST.
1. BA200 TDA 7294 (STEREO / BRIDGE) VERSION.1
FIRST VERSION hum.😱😕
VERSION.2
BA200(TDA7294 VERSION 2) AUDIO VERY GOOD😀😀😎😎
2. Ax11 HIFI STEREO (PCB FROM wiljj78) THANKS MR wiljj78!!!! 😀
3. Protect and Clip APEX PSU PCB 😀
SORRY, IMAGE QUALITY AND MY BAD ENGLISH
THANK YOU MR MILE GIVE ME A LOT OF SCIENCE.
GREETINGS TO ALL, THIS IS MY FIRST POST.
1. BA200 TDA 7294 (STEREO / BRIDGE) VERSION.1
FIRST VERSION hum.😱😕
VERSION.2
BA200(TDA7294 VERSION 2) AUDIO VERY GOOD😀😀😎😎
2. Ax11 HIFI STEREO (PCB FROM wiljj78) THANKS MR wiljj78!!!! 😀
3. Protect and Clip APEX PSU PCB 😀
SORRY, IMAGE QUALITY AND MY BAD ENGLISH
Yyoyyox you posted TDA7294 Amp in a wrong thread....
You should post these here http://www.diyaudio.com/forums/chip-amps/162179-tda7294-stereo-bridge-psu.html
Regards,
You should post these here http://www.diyaudio.com/forums/chip-amps/162179-tda7294-stereo-bridge-psu.html
Regards,
THANK YOU MR MILE GIVE ME A LOT OF SCIENCE.
GREETINGS TO ALL, THIS IS MY FIRST POST.
1. BA200 TDA 7294 (STEREO / BRIDGE) VERSION.1
FIRST VERSION hum.😱😕
VERSION.2
BA200(TDA7294 VERSION 2) AUDIO VERY GOOD😀😀😎😎
2. Ax11 HIFI STEREO (PCB FROM wiljj78) THANKS MR wiljj78!!!! 😀
3. Protect and Clip APEX PSU PCB 😀
SORRY, IMAGE QUALITY AND MY BAD ENGLISH
Nice work, what is the post number with AX11 stereo pcb design?
Regards