Respect to alex mm and maxwell007.
You have built extremely beautiful devices.
Whatever I do, my devices look like they're made with an ax.)))))
And other times I've been showing my old A40, but in the spirit of the theme again.
YouTube
A40 became my favorite when I was in a direct match over my previous favorite .....
A40 sounds better.
YouTube
You have built extremely beautiful devices.
Whatever I do, my devices look like they're made with an ax.)))))
And other times I've been showing my old A40, but in the spirit of the theme again.
YouTube
A40 became my favorite when I was in a direct match over my previous favorite .....
A40 sounds better.
YouTube
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hi sir. i have build A40 a day ago and tested. there is an issue. the issue is with offset pot. when power supply is connected there are some voltage at output and offset pot does not do any thing to offset voltages. other than that two transistors MJE340 and 350 at input stage are heating up without any signal. pcb is my own designed.
thanks for reply. i have attached my pcb if you can look on it. if you have unmirrored black pcb layout of alex,s pcb then give me please. i realy want to build this amp.
hi alex. i have some issues with my pcb. i cant adjust offset with pot. is there should be 470k or 470R resistor and is it normal for mje340, 350 at input side to get hot even on low operating voltages ?.Hi all,
The latest revision of PCBWill be ready this summer .
BR Alex
can you give me files please?
Attachments
rehman.....I do not understand English well, but as far as I understand you have a problem with the scheme.
If the board is executed correctly, there should be no problem, and it works from the first time.
You have to be careful with the bindings and there is no shortage of tracks. It happened to me but I found it.
I would help with what I can, but the language is very disturbing to me.
Please someone help him urgently because this man deserves the A40.))))
If the board is executed correctly, there should be no problem, and it works from the first time.
You have to be careful with the bindings and there is no shortage of tracks. It happened to me but I found it.
I would help with what I can, but the language is very disturbing to me.
Please someone help him urgently because this man deserves the A40.))))
just one last question please someone solve my confusion.
Use 470K resistor with offset pot, but amp also will work with 470R, this is not your problem. You made some mistake on your build, post pictures if you need help. All schematics and pcbs is 100% working.
It will not working properly, for sure. Using 470kohm means DC gain of 0.2, 470ohms means DC gain of 50, which will affect the DC stability.
Sajti
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thanks for reply. i will go with pcb i have attached with 470K.
can i use 2w resistor instead of 3w
hi i powered a40 with +-70V dc but it was not a good step. something is damaged in pcb and now circuit is not working properly. there is still no ofset voltage but the output is much distorted.
Hello rehman.
I do not see a reason to feed on such high voltage boards unless you are looking for high power. If you are looking for power, I advise you to do like me. 2 bridge bridge channels. with maximum high idle current. The deeper A40 in Class A, the better the quality. In my bridging tests, my tests showed great results. The voltage is about 56 volts, an idle current of 800 mA. Great sound. Stunning speaker control. Of course, everyone can disagree with me, but I believe what they hear my ears. I'll show you soon when I finish the boxes of monoblocks.
I do not see a reason to feed on such high voltage boards unless you are looking for high power. If you are looking for power, I advise you to do like me. 2 bridge bridge channels. with maximum high idle current. The deeper A40 in Class A, the better the quality. In my bridging tests, my tests showed great results. The voltage is about 56 volts, an idle current of 800 mA. Great sound. Stunning speaker control. Of course, everyone can disagree with me, but I believe what they hear my ears. I'll show you soon when I finish the boxes of monoblocks.
This is very important.
In the original form there is not much power A40 ..... about 100 watts.
So I recommend a bridge connection.
Then it becomes 200 watts at 8 ohms, and 400 watts at 4 ohms at high quality.
Then you can also use XLR which is a huge advantage
The problem is that you have to put two more boards, and do not forget the power supply.
Here are the tensions
In the original form there is not much power A40 ..... about 100 watts.
So I recommend a bridge connection.
Then it becomes 200 watts at 8 ohms, and 400 watts at 4 ohms at high quality.
Then you can also use XLR which is a huge advantage
The problem is that you have to put two more boards, and do not forget the power supply.
Here are the tensions
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I'm ready for my first a40 friends. I hope it goes perfect like that of all of you
https://www.diyaudio.com/forums/attachment.php?attachmentid=768523&stc=1&d=1563245155
https://www.diyaudio.com/forums/attachment.php?attachmentid=768523&stc=1&d=1563245155
