
Warning!
This PCB contains a high-voltage power supply; thus, a real and lethal
exists. Once the power transformer
is attached, be cautious at all times. In fact, always
assume that the high voltage capacitors will have retained their charge e
power supply has been
disconnected or shut down. If you are not an experienced
electrical practitioner, before applying the AC
voltage have someone who is
experienced review your work. There are too few tube-
loving solder slingers left; we
cannot afford to lose any more. Overview
Thank you for your purchase of the GlassWare Aikido 5687 All in One 9-
PCB. This FR-
4 PCB is extra thick, 0.094 inches (inserting and pulling tubes from their
sockets won’t bend or break this board), double-sided, with plated-through heavy
copper traces. In addition, the PCB is lovingly an d expensively
board is 7 by 6 inches, with five mounting holes, which helps
bending while inserting and pulling tubes from their sockets.
Each PCB holds two Aikido line-
stage amplifiers; thus, one board is all that is needed
for stereo unbalanced use (or one board for one channel of balanced amplification).
including the necessary components for the heater and high volta
on the PCB, the5687 All in One board makes building a standard-
amplifier a breeze. This assembled board with a chassis, volume control, selector
switch, power transformer, and a fistful of RCA jacks is all that is needed.
PCB Features
B+ and Heater Power Supplies On the 5687 All in One board, two power su
reside, one for the high-voltage B+ for the tubes and a low-
voltage power supply for the
heaters. The high-voltage power supply uses an RC filter to smooth
the low-voltage power supply uses an LDO
voltage regulator to provide a stable and
noise-
free voltage output. The power supplies require an external power transformer(s)
with two secondary windings, one for the B+ voltage and one for the heater
supply.
Redundant Solder Pads This board holds two sets of differently-
for each critical resistor, so that radial and axial resistors can easily be used (
bulk-foil resistors and axial
film resistors, for example). In addition, most capacitor
locations find many redundant solder pads, so wildly differing-
capacitors can be placed neatly on the board, without excessively bending their leads.
Two Output-Stage Topologies The output stage can
be configured either as the classic
Aikido line amplifier or as an Aikido headphone amplifier. The 5687 is a robust
that can deliver a lot of current at relatively low voltage
s, making it ideal for driving
headphones or other low-impedance loads.
Power-Supply-Decoupling Capacitors The 5687 All in One
two sets of capacitors to decouple both Aikido gain stages from the B+ connection and
each other. This arrangement allows a large-valued electrolytic capacitor and small
valued film capacitor to be used in parallel, while a series voltage-
completes the RC filter.
GlassWare Audio Design