dc offset
first of all if you have a problem with dc offset first thing you should check is the differential transistor and the current sources and tail current.the potentiometer is responsible for dc bias if you change value you will have problem with getting the ideal bias voltage.compare my schematics with apex .when my schematic is wrong my layout also.check also resistor value and capacitor polarity.check polarity of c6 and compare to apex schematic.i think eventhough its wrong polarity it will not cause trouble.i dont have apex schematics right now so i cannot compare. And also make sure the gnd is connected to chassis along with the power supply gnd.
first of all if you have a problem with dc offset first thing you should check is the differential transistor and the current sources and tail current.the potentiometer is responsible for dc bias if you change value you will have problem with getting the ideal bias voltage.compare my schematics with apex .when my schematic is wrong my layout also.check also resistor value and capacitor polarity.check polarity of c6 and compare to apex schematic.i think eventhough its wrong polarity it will not cause trouble.i dont have apex schematics right now so i cannot compare. And also make sure the gnd is connected to chassis along with the power supply gnd.
What the resistor value you use on the base-colector of VBE?
I was have same problem, maybe you can try this
I use 1k2 & working 🙂 🙂
R22(base-emiter) on my AX17 is 220R & I bypass P1(bias) for 100mA bias 😀😀
With that higher resistor value you can easily get more bias on output
Regards
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I use PCB from post 1023, that was "hand made" PCB...
& there is little mistake on that PCB...
attachment post 1140 is the correct lay out.
You must use ExpressPCB to open the file.
"there is AX 17 TO.gif & not matched to the .pcb file"
that my false, I'm sorry to make confuse any other.
I will post picture of AX17 when I fix it C6 & I will use SanKen at output
Regards
& there is little mistake on that PCB...
attachment post 1140 is the correct lay out.
You must use ExpressPCB to open the file.
"there is AX 17 TO.gif & not matched to the .pcb file"
that my false, I'm sorry to make confuse any other.
I will post picture of AX17 when I fix it C6 & I will use SanKen at output
Regards
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clear...
thanks john for claryfying and may he solved the problem.yes apex did correct me on c6 and have already change the value on my last upload.
Regards
joel
thanks john for claryfying and may he solved the problem.yes apex did correct me on c6 and have already change the value on my last upload.
Regards
joel
John/Joel,
Thanks for the help. I did as you and Mile's suggested and replaced with 1.2k left the trimpot and 220R. Adjusted fine to ca 100ma (30mv on .33R's) for the dual staged amp.
Thanks, JPR
Thanks for the help. I did as you and Mile's suggested and replaced with 1.2k left the trimpot and 220R. Adjusted fine to ca 100ma (30mv on .33R's) for the dual staged amp.
Thanks, JPR
i'm glad..
nice to see that your amp. Is working .feedbacks and post pictures are highly appreciated.enjoy.
Regards,
joel
nice to see that your amp. Is working .feedbacks and post pictures are highly appreciated.enjoy.
Regards,
joel
My AX14 by APEX Redraw Jhon BALI
I can not say anymore but I'm holding thumbs for the AX14. with a clear voice and a clear vocal sound. I use the car speakers with a homemade box. APEX and thanks for the layout of the components in the image repeated by John Bali from my country Indonesia.
https://lh4.googleusercontent.com/-...AAAAAAAAxY/HfwEPHVN1cE/s817/Dalimunthe857.jpg
https://lh3.googleusercontent.com/-...AAAAAAAAxg/fpZXwGVgG50/s817/Dalimunthe858.jpg
https://lh4.googleusercontent.com/-...AAAAAAAAxc/TwFcGfqk7RQ/s817/Dalimunthe859.jpg
https://lh4.googleusercontent.com/-...AAAAAAAAxw/nHa8SdEOn9Q/s817/Dalimunthe860.jpg
https://lh6.googleusercontent.com/-...AAAAAAAAx0/VAaS-k85Aao/s817/Dalimunthe862.jpg
https://lh5.googleusercontent.com/-...AAAAAAAAyA/3oV9zr7tAIg/s817/Dalimunthe863.jpg
I can not say anymore but I'm holding thumbs for the AX14. with a clear voice and a clear vocal sound. I use the car speakers with a homemade box. APEX and thanks for the layout of the components in the image repeated by John Bali from my country Indonesia.
https://lh4.googleusercontent.com/-...AAAAAAAAxY/HfwEPHVN1cE/s817/Dalimunthe857.jpg
https://lh3.googleusercontent.com/-...AAAAAAAAxg/fpZXwGVgG50/s817/Dalimunthe858.jpg
https://lh4.googleusercontent.com/-...AAAAAAAAxc/TwFcGfqk7RQ/s817/Dalimunthe859.jpg
https://lh4.googleusercontent.com/-...AAAAAAAAxw/nHa8SdEOn9Q/s817/Dalimunthe860.jpg
https://lh6.googleusercontent.com/-...AAAAAAAAx0/VAaS-k85Aao/s817/Dalimunthe862.jpg
https://lh5.googleusercontent.com/-...AAAAAAAAyA/3oV9zr7tAIg/s817/Dalimunthe863.jpg
Lookin´ really good,how does it soud? If it is like NX or simmilar than you have a plenty of power that sounds really good! Yesterday for the first time i have pushed it to the limit and it reached 100W into 8Ohm speakers just like that! No hearing sound distorsion,i wouldn´t know that it was at that power if there was no clip-indication from APEX PSU clip+protection. As i understood it blinks when voltage at speaker reaches PSU - 6V. The PSU voltage is +/- 50.5 V (APEX PSU10) so the Vp was 44V...just like that! With IRFP20 in output it has a little bit more power,but when you cross over 60W than the power is not important,just the sound.
Great job DAMANHURI! 😉
Great job DAMANHURI! 😉
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Why, what's wrong with treble response of AX14? If you want more treble use equliser or preamp with tone controls for bass and treble.
feel less treble and more bass in ax-14
may be of fake mje350 and mje 340 ?
if fake mjes are used is there any chances to less hf response?
can i change input capacitor to 0.1uf mylar capacitor for brightness
Hi! Sir Apex,
It's been a while guess I have lost track of the progress in this thread...🙁😀
Actually I have been keeping these files for my future DIY project and I guess it's about time...will these pair of circuit work effectively? (below image)
However I may have a problem acquiring BC517, any sub for this transistors?
Also what could be the safe value for T5A (thermistor) in the soft start.?
I assume the protect terminal of the amp connects to the protect terminal of the PSU? Kindly clarify would there be any component changes on both circuit. I will be using +/-50vdc rated at 500w.
Guess I have asked too much 🙂
Regards!
It's been a while guess I have lost track of the progress in this thread...🙁😀
Actually I have been keeping these files for my future DIY project and I guess it's about time...will these pair of circuit work effectively? (below image)
However I may have a problem acquiring BC517, any sub for this transistors?
Also what could be the safe value for T5A (thermistor) in the soft start.?
I assume the protect terminal of the amp connects to the protect terminal of the PSU? Kindly clarify would there be any component changes on both circuit. I will be using +/-50vdc rated at 500w.
Guess I have asked too much 🙂
Regards!
