Yes, eliminate external wiring from the input pads on the board.
You have just the board and speaker attached together with the three wires to the power supply, so plus, minus and ground.
The input of the amp is shorted to ground at the board terminals. Any wire you had going off to the sockets are disconnected.
This allows the amp to run in total isolation on its own. With the inputs shorted it should be quiet.
You have just the board and speaker attached together with the three wires to the power supply, so plus, minus and ground.
The input of the amp is shorted to ground at the board terminals. Any wire you had going off to the sockets are disconnected.
This allows the amp to run in total isolation on its own. With the inputs shorted it should be quiet.
Hi Mooly,
so, replacing the jfets didn't work aswell...
While biasing and testing I a put apiece of wire across inner and outer contact of my rca jacket to keep it quiet.
Is that enough or should i desolder the leads?
so, replacing the jfets didn't work aswell...
While biasing and testing I a put apiece of wire across inner and outer contact of my rca jacket to keep it quiet.
Is that enough or should i desolder the leads?
Desolder the leads. That way there is no doubt whatever of any external influence.
You should just have five leads to the board, minus supply, plus supply, ground from the PSU and two wires to the speaker.
You should just have five leads to the board, minus supply, plus supply, ground from the PSU and two wires to the speaker.
Have you tried rotating the transfomer around its axis or between vertical and horizontal orientation ?
Maybe in your temporary chassis its orientation was different in relation to the Jensen than now. Toroids have radiation "lobes" and radiate more in certain directions than others.
Regards, Claas
Maybe in your temporary chassis its orientation was different in relation to the Jensen than now. Toroids have radiation "lobes" and radiate more in certain directions than others.
Regards, Claas
Success!!! 😀
The hum is gone.
Even with removed input leads it was still humming.
So i decided to throw everything unneccessary out.
That included my speaker protection and the wires to the Front LED.
Then it was silent.
I Think the board picked up the hum through the led wires... crazy.
The Wiring was exactly the same as in my second channel, so i thought that should not be the problem.
I was wrong 😱
Now i have to rethink some Wiring...
But i will sein this opportunity to put in my new speaker protection, that i designed 😀
The hum is gone.
Even with removed input leads it was still humming.
So i decided to throw everything unneccessary out.
That included my speaker protection and the wires to the Front LED.
Then it was silent.
I Think the board picked up the hum through the led wires... crazy.
The Wiring was exactly the same as in my second channel, so i thought that should not be the problem.
I was wrong 😱
Now i have to rethink some Wiring...
But i will sein this opportunity to put in my new speaker protection, that i designed 😀
Great that you solved it ! 🙂
Chasing hum is often still a lot of trial and error, despite all the best practices around ... 😛
Chasing hum is often still a lot of trial and error, despite all the best practices around ... 😛
That was a bit of a strange one but great to hear its all OK.
You will just have to build it up one step at a time and see where the hum is introduced.
You will just have to build it up one step at a time and see where the hum is introduced.
Yeah, i think so too.
But this time it's a easier, because the Front led will now be Powered by the speaker protection board and not the amp.
So its better isolated then before 🙂
But this time it's a easier, because the Front led will now be Powered by the speaker protection board and not the amp.
So its better isolated then before 🙂
One of those cases where you would have to have it in front of you to see what was going.
The LED and series resistor I assume is just across a rail and so that can not really introduce anything untoward. Very odd 🙂
The LED and series resistor I assume is just across a rail and so that can not really introduce anything untoward. Very odd 🙂
Two thumbs up on your successful trouble shooting @KampfKeks3000 . You stuck with it and it paid off!
Thanks @ Spe@kerBox 🙂
I don't give up that easily.
@ Mooly
Yes, you are right. It's really odd.
Maybe the hum was introduced via the ground lead of the led, but that's really unlikely.
Or it came from one of the leads of the speaker protection.
It has one lead to positive DC rail and one to the related AC voltage before the rectifier to sense power up and power loss.
Maybe this circuit got slightly damaged by my polarity fault.
Seems to be more likely 🙂
I don't give up that easily.
@ Mooly
Yes, you are right. It's really odd.
Maybe the hum was introduced via the ground lead of the led, but that's really unlikely.
Or it came from one of the leads of the speaker protection.
It has one lead to positive DC rail and one to the related AC voltage before the rectifier to sense power up and power loss.
Maybe this circuit got slightly damaged by my polarity fault.
Seems to be more likely 🙂
Good thing you solved the humming issues. Time to enjoy the amp.
Really like your chassis design, where the trafo is housed in its own chamber.
Really like your chassis design, where the trafo is housed in its own chamber.
Hello my fellow diyers.
I just wanted to inform you that it seems like package coming in from Italy to Us is being affected by the Covid19. I've ordered my chassis on May 17th and it is stuck in Germany. I just called the Fedex and the representative said that i may stay there indefinitely. This is an act of the nature/noone at fault. But I wanted to share my experience with you all.
Happy buillding, and we will beat this virus together.
I just wanted to inform you that it seems like package coming in from Italy to Us is being affected by the Covid19. I've ordered my chassis on May 17th and it is stuck in Germany. I just called the Fedex and the representative said that i may stay there indefinitely. This is an act of the nature/noone at fault. But I wanted to share my experience with you all.
Happy buillding, and we will beat this virus together.