Nelson Pass First Watt F5 [work in progress]

„All in one“ F5

Schematic taken from Nelson Pass „First Watt“ Website.  Parts designation same as used in the description from the pdf.
Each power rail got 94.000µF, a stereo amp have all together 376.000µF.
Star grounding on PCB to one GND point.

mounting RG178 without connector on the PCB:

thermistors mounting:

Fabric protective sleeve or shrinking tube is needed to mount the ptc thermistors.

 

 

 

thermal coupling:

use a little bit thermal grease between the two transistors. Hold them together with a cable tie or better take a stripe metal.

 

 

 

 

 

Heat sink, ~0,2K/W:

Improvement of the coupling between Mosfet and PTC resistor with a copper platelet. 15x15x2mm:

 

Mechanical work on the case:

230VAC wiring and PCB of the inrush current limiter, filter and DC filter in the bottom of the amplifier. 

Rear of the amplifier with the RCA sockets and the speaker connections.
In the lower half the mains switch and the Neutrik mains socket:  

Underside with perforated sheet metal cover and stands:

Back panel, heat sink and the other sheet metal parts are painted black.

230VAC wiring and PCB of the inrush current limiter, filter and DC filter in the bottom of the amplifier. New is the Ardunio UNO, which is responsible for the display and 1-Wire temperature sensors. 

The display has an RGB backlight. When the amplifier is cold, the display is blue, after reaching the operating temperature, the colour changes to red.

Wiring of the toroidal transformer to the circuit boards:

Input and output wiring:

Cover made of 40% transparent black acrylic glass:


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