I build SR200 and B500 both of them is fine,good quality,but when I build ax14, I got in trouble the first time,
please heklp me
please heklp me
Thanks for help, today I replaced resistor to 1k5 but still same problem. I'll like to know voltage between collector-emitter of BD139(Amp has 1.5V), Other amp NX-14 which I have build previously have 6.7V at collector-emitter of BD139.
Hi Apex, I want to make AX14 driver TEF scheme like this, is there any scheme is correct?
thanks
thanks
thanks for the super fast response, but I want to make power with 6-pair transistor finals, so i separate driver circuit with transistor circuit finals. is there any wrong track with my PCB schematic? i'm sorry my with english
regards
regards
thank you for the correction, and this picture after my revision, and I hope this is true ...
Uh Oh!
So the 2 fuses blew on one of the boards. Replaced and started poking around with the multimeter and now I have 12.6V on BOTH outputs!!!
The output transistors all seem to test fine - could the inputs be blown now?
Not sure what caused the fault but the bias seems to adjust properly on both channels...
The 12.6V is on BOTH the input and the output...
UGH!
So the 2 fuses blew on one of the boards. Replaced and started poking around with the multimeter and now I have 12.6V on BOTH outputs!!!
The output transistors all seem to test fine - could the inputs be blown now?
Not sure what caused the fault but the bias seems to adjust properly on both channels...
The 12.6V is on BOTH the input and the output...
UGH!
Do you connect GND from PSU to amp input (red line)?
Attachments
OK I wired up as prescribed and I have really bad hummmm
Offset is good less than 10mV, bias is 70mV on 0.22 resistor, voltage is 40v.
Offset is good less than 10mV, bias is 70mV on 0.22 resistor, voltage is 40v.
All right...I disconnected the input ground wire to the PSU ground but kept the input ground to star ground. Another wire from input ground to PCB input ground.
Now the amp again is very silent.
I had a bad trace on the mje15031 and was not getting a signal...
I am glad to report back that bias, humm, and sound are all back under control.
Now the amp again is very silent.
I had a bad trace on the mje15031 and was not getting a signal...
I am glad to report back that bias, humm, and sound are all back under control.
hello vostro,,my ax14 still like the time, I use your wiring but the result is still the same, and I do take advice from Mr.Mile to 100nF leading to gnd.the result still the same, ax14 shouts mixed humm but works.please help me vostro
try only running input ground to chassis star ground and to PCB ground.
It helped with my setup and DC offset is less than 10mV.
Board ground and speaker ground go to PSU "ground" point.
! wire goes from PSU ground point to chassis star ground and earth ground from power inlet goes to chassis ground.
No hummm/buzz anymore.
It helped with my setup and DC offset is less than 10mV.
Board ground and speaker ground go to PSU "ground" point.
! wire goes from PSU ground point to chassis star ground and earth ground from power inlet goes to chassis ground.
No hummm/buzz anymore.
Hi Cerna,
I noticed there was an error on the PCB track that you created in post 1798, this I include the correction
Regards Denmas😉
