Unique CFA 120/230W amp

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#102
dadod said:
Just one thing you don't want to change, capacitors for DC servo, C18 and C19, and I don't understand why.
Cheers, Damir
Click to expand...

Sorry to tell you but those caps are in place , just look closer in yellow first pic, and red circle in the second pic ....🙄
Alex
 

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#103
alex mm said:
Sorry to tell you but those caps are in place , just look closer in yellow first pic, and red circle in the second pic ....🙄
Alex
Click to expand...

Oh yes, I was looking the same position where you still have 5mm spacing and did not notice added caps. My apologies for that.
Now we have the PCB with all output transistors on one side and two possibility to fix it to the heat sink, perpendicular and parallel. I prefer perpendicular as in that way the PCB and electronic components are less heated from the hot heat sink, but if someone like to put it parallel it is possible now.
Thank you Alex, I still did not finish connection check, how sure you are that all is correctly connected?

regards, Damir
 
#104
PCB rev 2.5

I have check again ,found only one bad connection ,corrected now ,and I think are no more errors IMHO 🙂 so we can move ahead.....
Alex
 

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#114
In post #105, Alex has posted a double sided PCB layout, but no Gerber files. I am not sure if this was intended for iron-transfer method, but connecting every 'via' is challenging as much as aligning the top and bottom layers.

However, with some suggestions from anyone here, I offer to assemble and test the prototype, so that the Group Buy can be arranged.

If Alex can share the Gerber files, I could get a local manufacturer to produce sample boards and after testing the actual production boards. I believe the cost and quality should be comparable to the best boards from China.
 
#119
dadod said:
Sorry, could you be more specific, I don't understand what you ask?
Click to expand...

In #16, you posted the loop gain plot.
The plot shows that the phase starts around +40 degrees from the left, but I think it should go from +90(or -270?) degrees from the left and decrease towards the right.
I believe normal loop gain plot phase should start from 0 degree and decrease.

Is it ok?
What trick is used to do so?
And, why does normal loop gain plot phase start from 0 degree?
 
#120
xianrenb said:
In #16, you posted the loop gain plot.
The plot shows that the phase starts around +40 degrees from the left, but I think it should go from +90(or -270?) degrees from the left and decrease towards the right.
I believe normal loop gain plot phase should start from 0 degree and decrease.

Is it ok?
What trick is used to do so?
And, why does normal loop gain plot phase start from 0 degree?
Click to expand...

This depends how DC servo was connected for the LG simulation, before or after Tian probe. In this case it's connected to the amp output, if connected after Tian probe phase start from 0 degree.
When I simulated this LG I wanted to see DC servo influence on the Loop Gain.
 
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