Elektor Fortissimo-100 Power Amplifier Kit
●
22
At this point, finish fitting the rest of the components on the small PCB:
T23, T26, T27, T24, T25, K5, Faston tabs K8 and K9 (including two
8-mm M3 screws/nuts/washers and finally, the inductor (13 turns of
1.5-mm diameter enameled copper wire), and relay RE1. The compul-
sory output inductor L1 is made of 13 turns in a single layer using 1.5-
mm diameter enameled copper wire. The Inside diameter should be
10 mm. A 10-mm drill bit can be an aid in winding the inductor. Keep
the two ends long enough to place the inductor above R76 and check if
the distance of the two ends corresponds with the footprint and are in
line. R76 suppresses possible ringing. Use a hobby knife to scrape the
enamel insulation off the inductor wire ends, then pre-tin them lightly.
LED5 is to be mounted on the front of the enclosure of the amplifier,
and is connected by thin stranded wire, if so desired.
11 – Small Transistors, LEDs, Radial Power
Resistors, and Large Capacitors
Figure 22. Small transistors, rectangular LEDs, radial power resistors
and large capacitors soldered onto the amp board.
Now, T5, T6, T7, T8 and LED1, LED2, LED3, LED4 can be inserted and
soldered. For best thermal coupling, Place the chip inside the LED half-
way the package of the transistor that’s next to it, and flush against
the transistor.
