A guide to building the Pass F4 amplifier

I've searched this thread to find what to use for thermistors at the AC mains inlet, no results. Additionally looking for a value for what appears to be the cap at the ground to chassis point.
Maybe not the inlet at the IEC, but those on the terminal strip in the original post.
Limiting inrush current sounds good and less work than a soft start, but not sure I understand either enough to know if the thermistors have a similar effect as a soft start or if only to prevent arcing.
I see a mystery to me part in ori0nzbelt's BOM - 3300pF ceramic disk capacitor... I'm not building the PSU the same way, but with monolithic bridge rectifiers so don't know which part it is related to.

quoted form the first post:
IMG_1504_zps2330b348.jpg

Left to right we have post 1, 2, 3, 4

POST 1 - Transformer primary 'B 0' which will be connected to AC Neutral at post 2, through the thermistor between post 1 and 2.

POST 2 - AC Neutral in (not shown in photo), connected to Transformer primary 'A 0" , a thermistor to post 1, and a line cap to post 3

POST 3 - AC Hot in, connected to transformer primary "B 120", thermistor to post 4, and line cap to post 2

POST 4 - Transformer primary "A 120", connected to AC Hot through the thermistor to post 3

If you look at the red and black wires in the photo you will see that the Mains AC must to pass through a thermistor to connect to each of the 2 primaries. And that is the point of them, to keep inrush under control during power up.

c18876a2-f60a-4a7c-88c1-df7c2333efdb_zps3ff1ace7.jpg
 
Limiting inrush current sounds good and less work than a soft start,
Limiting the starting current with a Power NTC Thermistor is a "Soft Start".

For 110/120Vac mains the CL60 is a good choice for larger transformers.
For 220/240Vac one generally needs a lot more resistance, typically 20r to 100r depending on transformer being started.

BUT !!!!!!
for all these, the performance of the transformer and the following PSU is compromised if the resistance is left permanently in the mains line.
You really should arrange some mechanism to remove the resistance for best Transformer/PSU performance.
 
Hi 6L6
My F4 boards are ready stuffed exception of power transistors.
I always in admiration about yours finished pcb showed in build guides.
What chemicals give such good clean results ?
Greetings :):wrench:
 

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Thanks @ Mcendmar , Triodethom , Marra and 6L6 for councils and links

Think i try something in between ipa ,aerosol product to see what happen
and next time higher quality solder like Cardas
if i write the letter to Santa Claus :)
Now components for power supply
i have four huge caps like this but is to much ?
Greetings
 

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