Don't mind me. I'm just getting situated here.
What's in the box?

A little inventory to get the lay of the land.

I think Jeff has really raised the bar a few more notches on this kit.

OK. . . from the top. Jeff suggests building the Main PCB first. The parts needed are pictured below:

Referencing the BOM, I identify and sort all of the electronic components.

Make sure you are able to read the small markings on the ceramic capacitors.

First, I place my resistors.

Then, bend the leads and solder from the back side.

And, we're populating. . . CR1 and CR2 were next. Generally, I just place the components in order of shortest to tallest.


Polarity matters on the Electrolytic capacitors. Make sure you align the stripe side with the "-" marked holes. Also, the longer of the legs on the radial caps are "+". It does not hurt to triple check these before soldering.


Next, locate the opamp sockets for A1 and A2.

Insert these from the back side of the PCB.

I had to set my soldering temp up significantly to get these to flow in smoothly. I solder from the back side and attempt to just flow the solder down into the front side of the PCB securing the sockets.

When new, the sockets are REALLY stiff. . . so, if you are building your own opamps, now is a good time to run one of the loose pins into and out of each socket a couple of times. This will make initial insertion of opamps much easier and you run a smaller risk of bending pins.

This PCB is now ready for CMRR calibration. . . but, I happen not to have op-amps on hand for the build. According to Gary's post in this thread, it seems the GAR1731 is a VERY tasty choice for this build and it makes a lot of logical sense in an EQ especially when cranking on those frequencies to have the smooth 1731 in line. So, for me. . . for this build, I'll start out with some GAR1731's. NOTE: Please test opamps thoroughly prior to using them in a fresh build.
Since I'm actually building a pair, I will need 4 GAR1731's. Each EQ requires 2 opamps. There are a lot of flavors and excellent options available from Classic Audio Products. I usually default to the GAR2520 complete kits because they have performed really well for me as a nice baseline that is true to the vintage API sound. . . and I'm cheap, but Jeff also carries Scott Leiber's nice red dot and blue dot assembled op amps and for that matter assembled and tested GAR2520 and GAR1731 op amps as options on these LC53A kits.
It's slow but therapeutic to build op-amps, so I decided to build a few up myself.

and, we're populating.








And there we are. . . 4 freshly hatched GAR1731 op-amps.

With opamps built, I set up for CMR calibration per the VC528 instructions and jeff's assembly aid document posted above. This is the way I have configured my JLM powerstation for 51X use, and it is handy for testing and calibration on the bench.

In this thread, a very slick calibration adapter is pictured that I think is absolute genius. Not so much genius but equally functional is my calibration cable that I made per the VC528 CMR calibration instructions with 2 closely matched resistors. These were the photos taken when I made my cable re-posted here as they are pertinent to this build.


Here I mark the cable so I know it's a calibration cable.


Setting aside the "-" cable on one end to feed identical signal to pins 2 and 3.


and the other end of the cable wired as normal

My test cable complete.

Here, I set up my 400Hz signal on a function generator and send through my special test cable into the main board. I also connect my scope to the negative side of C2.


notice, per the instructions, I am using a tested/proven GAR2520 instead of my freshly hatched 1731 for this calibration. I did confirm on my new opamp though to verify that the setting was the same on the opamp designated for this build.
I also connected the ground of my scope to the common terminal on the other opamp. It's here that I accidentally shorted the common to the -16V rail and created black smoke on my power supply which required a full stop and a trip to the electronics store


Please use caution if you decide to use this terminal in your testing. I used it because it gave me a slightly cleaner visual from my scope to observe because I was at the limit of my instrument's ability to read with such a small signal.
With a few twists on the trim pot, I was able to reduce the signal to the lowest measurable level on my scope.

I increased the output of my signal generator a bit so I could see a slight sine wave change continuously all the way through the lowest point of adjustment and set my trim pot there. Hopefully this methodology is sound.

Previously, I used the DAW method in studio to calibrate my VC528's, but I do not have a functioning DAW currently at my house, so I decided to try the scope this time around. If I recall correctly, the DAW method was just as accurate if not a bit easier. Certainly it did not involve frying my test power supply.