7. Assembling the back panel
Pre-soldering
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Put the AC inlet and RCA jack on the back panel.
Put the vinyl sleeve cover on the soldered part to
prevent electrical shock and shorting.
The ability of soldering neatly to RCA jack is by putting the spare solder on both
terminal of the lead and RCA jack beforehand.
By doing this, it will melt together neatly providing good soldering coverage. For the
HOT terminal, covering the thermal contraction tube will protect the electric short
with other signals.
Attach 2 lock washers as shown in the picture on the left. One is with lead of GND.
This prevents making too much space between the knob and front panel because the 2 lock
washers for the volume control sticks out from the front panel. The lock washers make the
electric connection secure between the Volume control body and chassis ground. The
chassis is made out of a black anodized plated aluminum.
Since the volume is made of a conductive plastic material it will cause a humming noise to
occur when you touch the knob, so certain connection between Volume control body and
chassis ground is required. This is one technique for good SNR.
Attach the RCA jack to the back panels by
sandwiching the plastic washer on the back and
front.
This is to prevent the jack from coming into
contact with the electrical panel.
Wiring of the GND will be dropped from a power
supply substrate on the chassis later.
This is one technique for good SNR.
otomatsu
Balanced Headphone Amplifier kit , BDR-HPA1E
