Hello apexaudio,
I have a question; for Q12 and Q11 I used a BC639 and BC640 transistor is correct?
thanks
the welds look ok ..... do not understand why between base-emitter of both transistors (Q11 and Q12) are short-circuited ...
if you measure resistance between B and C of those transistors while they are on PCB than in one way there should be almost short circuit (directly polarised PN)and on the other way there should be about 40 Ohm resistance because connectins between R24,R25 and R27.
pay close attention at BC639-640 and BC327-337 pin-out,it is not the same! compare it with pcb layout and see if you fitted it right.
pay close attention at BC639-640 and BC327-337 pin-out,it is not the same! compare it with pcb layout and see if you fitted it right.
if you measure resistance between B and C of those transistors while they are on PCB than in one way there should be almost short circuit (directly polarised PN)and on the other way there should be about 40 Ohm resistance because connectins between R24,R25 and R27.
pay close attention at BC639-640 and BC327-337 pin-out,it is not the same! compare it with pcb layout and see if you fitted it right.
pay close attention at BC639-640 and BC327-337 pin-out,it is not the same! compare it with pcb layout and see if you fitted it right.
nothing to do ... not being able to solve the problem .... the signal "music" comes out, but is disturbed / distorted .....
Hi,
problem solved, the P1 470R regulator Bias, I had to adjust, almost at the end of the rotation to have a bias current optimal .... now operating normally.
But I think to replace P1 with a 1k higher quality. I listen to it and not just for testing, but the sound quality is really good and lots of power (already with 60-0-60) ...
problem solved, the P1 470R regulator Bias, I had to adjust, almost at the end of the rotation to have a bias current optimal .... now operating normally.
But I think to replace P1 with a 1k higher quality. I listen to it and not just for testing, but the sound quality is really good and lots of power (already with 60-0-60) ...
Hi,
problem solved, the P1 470R regulator Bias, I had to adjust, almost at the end of the rotation to have a bias current optimal .... now operating normally.
But I think to replace P1 with a 1k higher quality. I listen to it and not just for testing, but the sound quality is really good and lots of power (already with 60-0-60) ...
Nice work and good heatsinks
Regards
Thank you very much.
a question; my Heatsink measure 32cmx12cmx4cm and weighs 2kg, which can adjust bias?
Hello apex,
finished ..... what you think of 20 mV measured on 0.47ohm resistors, is too much?
thanks
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Hello apex,
finished ..... what you think of 20 mV measured on 0.47ohm resistors, is too much?
thanks
Nice work, it's about 40mA per transistor that's ok if heatsinks isn't hot too much
it will work very nice with lower bias,in my opinion,at least i haven´t heard any great difference.
i have adjusted it at about 15mV/0,47Ohm when the amplifier temperature stabilises with my heatsinks. when heatsinks are cold at start-up the bias ic bigger,but when heatsink reaches some temperature the bias stabilises at about 15mV.
i have adjusted it at about 15mV/0,47Ohm when the amplifier temperature stabilises with my heatsinks. when heatsinks are cold at start-up the bias ic bigger,but when heatsink reaches some temperature the bias stabilises at about 15mV.
Happy New Year apexaudio ..
about power voltage, I currently use two toroidal, 300VA (600VA total) 2x44 VAC (60-0-60), you think if I use two 500VA toroidal (1Kv) 2x50Vca, I naturally increase the power, but, the sound quality has increased?
greetings and happy holidays
