Next locate the caps for the pushbutton switches.
The pair of black ones go on the high pass filter PCB that was just assembled.
And the rest go on the main PCB. Red (48v phantom power), gray, white gray in that order.
Next, pull hardware to mount the main PCB onto the L-bracket.
Start by inserting the screws from the bottom of the L-bracket.
Tighten the rear standoffs all the way and install the front 2 half way only so the PCB can slide over and into position.
Pull Hardware to set the high pass filter PCB onto the main PCB.
Install the lock washer onto the screw.
Set the HPF PCB onto the main PCB.
And attach from the bottom with the screw/lock washer. Finger tight will do right now.
Carefully slide the main PCB assembly onto the L-bracket.
Pull hardware to set the main PCB.
Align the front of the PCB snug and square to the L-bracket and install rear star lock-washers and nuts.
With the PCB in position, we can now tighten down the front standoffs.
And install the small lock washers and nuts onto the front screws.
Verify that the main PCB is square to to the L-bracket and tighten all 4 nuts.
Pull hardware to mount the front of the HPF PCB onto the L-bracket.
Insert the star lock washer between the L-bracket and the HPF PCB assembly like this.
And insert small screw from the front and tighten down.
Locate the front panel and install.
Align the front panel to the 4 main PCB pushbuttons and to the L-bracket. Then, install the 2 grayhill switch nuts (discard the Grayhill switch lock washers).
Next, adjust the HPF PCB so the pushbuttons are aligned with the front panel. The screws holding this in should only be finger-tight at this point so the board can move. When happy with the alignment, tighten down these 3 screws to lock the HPF PCB into position.
From the cutout on the back side of the L-bracket, solder the HPF PCB header to the main PCB.
Next, pull the 5 LED's.
Cut and bend the leads like this. I chose to retain one short pin and one long pin when I cut the LED just for personal reference.
Carefully position one red and 3 yellow LED's onto the main PCB from the bottom of the L-bracket.
Notice the short leg of the LED's correspond to the silk-screened arrow mark.
Once happy with the LED positioning, solder the leads to the main PCB pads.
Pull the 2 clear sections of heat-shrink tubing.
cut these to reveal about 1/8" and slide them over the tall jumper near the front panel.
Next, connect the green LED to this jumper. Some bending will be involved. Please excuse my mis-matched shrink tubing. Shortly after taking the previous photo, I must have accidentally flung the supplied tubing piece across the room when putting the camera down and I could not find it, so I had to use another one from my kit which was not the same diameter.
The LED will end up looking something like this.
Make sure the short end of the LED corresponds to the silk-screened arrow mark on the PCB for this LED just like the others.
Carefully position the green LED and make any final tweaks necessary for a tidy fit.
And solder into position.
Next, I used some water on a Q-tip to clean off some of the residue left on the faceplate from installation.
Pull knobs and shaft adapter.
Use pliers to position both knobs in the 12:00 position (pointing straight up), and position the shaft adapter so the gap is facing down.
Press the adapter onto the Grayhill switch shaft until somewhat flush with the top of the post.
Install knobs.
Next, pull the 2 colored stickers that go on top of the knobs.
Peel off the paper backing and install.
For this build, we will need 2 opamps. I chose to use Gary Barnett's GAR2520 op amp kits for this build. These are fast becoming my go-to op-amps for API-type builds and sound phenomenal.
Pull the pins from the kits.
and insert into the opamp sockets of the main PCB. This positions the pins perfectly for soldering and also loosens up the sockets that can be extremely stiff the first time an opamp is inserted. It is much easier to insert the pins one at a time like this.
Place the GAR2520 PCB's onto the pins and solder in place.
Pins are perfectly aligned and the op-amps are ready to be populated. The documentation provided with the GAR2520's is VERY thorough and walks you step-by-step through the process. A steady hand and an eye toward detail are required. I will populate a pair to the best of my current ability.
and opamps complete.
Next, pull the IC that drives the green signal LED.
and carefully insert into the socket on the main PCB making sure to align the dot with the notch on the socket. Do not press the IC into position until you are absolutely sure all of the delicate pins are properly positioned in the socket.
Note the IC's orientation.
Next, install the 2 GAR2520 opamps or the +, -16V opamps of your choosing on the main PCB.
The VP28 is now complete. Humans win. . . again. If all went well, it should run right out of the gate.
I sincerely hope you've enjoyed this installment of "Build Jeff's Stuff' as much as I have and find this photo documentary helpful
March 15, 2020, 04:15:07 PM