19
Val
RM
VCO1
VCO2
VCO3
VCF
EG
VCA
MIX
Noise
VP
S&H
Amp
Total
Socket
6
1
4
1
2
1
7
3
3
3
2
33
10n
1
1
2
1
6
11
15n
1
1
1
3
100n 2
1
1
4
10u
6
1
2
9
Table 9 Main Phase 1 Ceramic Capacitors (10u are electrolytic)
12.
Install the backer board, tape, and flip the work. Find and clip the leads to all the capacitors. You
can find the count of caps in each section looking at the table. Solder everything, inspect, flip the
board back over and remove the cardboard.
13.
Using the same process as above, place all the small signal transistors (singles, duals types and
matched pairs). Set aside the MJE172 and MJE182 transistors for now
–
as they stand much higher
from the board.
Note that in the first batch of V4 (Synthcube) boards, the footprint of the 2N3954 in the
VCO2 section has pins 5 and 6 reversed. If you are building this main board, be sure to
form those pins on the 2N3954 to fix that bug. This dual JFET is used to shape the triangle
wave into a sine wave.
Figure 4 - Reversed Pins 2N3954 in VCO2. Note the image shows a different transistor, but the reversed pins are as indicated.
I start with the PNP/NPN complementary pairs (VCA and VCO2) adding thermal coupling as I install
them. Then I install the two CAN-6 JFETs (VCO2 and S&H). Next, the NPN/NPN and PNP/PNP
matched pairs. Lastly, all the singles.
When all transistors (singles and pairs) are in place, place the film caps in the Amp section. Put
on the cardboard, flip it over, clip the leads, and solder. Solder the capacitors first, then proceed
to the transistors. When soldering these parts, keep your iron temperature at or below
600f/315c, and work quickly. Going section by section, solder the first lead of each transistor,
then go back and do the second leg of each, then the third. This will reduce heat stress on the
transistors, and this is especially important for matched pairs and JFETs.
Val
RM
VCO1
VCO2
VCO3
VCF
EG
VCA
MIX
Noise
VP
S&H
Amp
Total
BC558
3
1
4
8