[BUILD] VC528 ST2+ 500/51x Support Thread...aka The Missing Link!

[jsteiger]

Hi to all

Since I have shipped a good handful of these “missing link” modules, I felt it time to start a customary, official, build and support thread. This is currently the most complicated module kit that I have at the store so I think this thread will be very important.

Do to some of the tricky physical nature of this build, I do already have an over-view, assembly aid PDF put together. Currently, this PDF is considered “preliminary”. Mostly due to the pics. What you will see in this pre-lim doc are just quick phone pics intended more as placeholders. These will also serve as a guide line, so that my hired photographer has an idea of what I feel is important. That hired gun is our resident “Newbie Builds...” guru ‘Chunger. After seeing the quality and professionalism ‘Chung completes his projects with, I felt it only natural to officially “hire” him for this one.

So, here is the pre-lim PDF. Feel free to let me know if you see anything that seems wrong or maybe unclear. This will probably be a work in progress for at least a few weeks.


Since the VC528 has a discrete, balanced, transformerless receiver stage, there is a CMRR trimmer that must be properly setup. I have recently finished a document that will guide those unfamiliar thru that process. That can be found here. I should point out that I do not recommend using a freshly built DOA in the receiver stage during this adjustment, unless you are 100% sure the opamp is functioning correctly. A stable and correctly operating DOA is a must for the CMRR adjustment to be right!


More detailed info on the circuit can be found here on my site.

Of course we have a dedicated 500 series mod for those naughty DIY types that have not joined the 51x party! Shame!  8)


And a bit of eye candy for fun…






************************
Recall Sheet pdf downloads:
1 module
2 modules
4 modules
6 modules
************************

Having trouble with your VC528 build?
Hopefully these Troubleshooting Tips will help

Happy building and fire away with any questions that may arise!
Jeff 

 

[mikefatom]

Whaaat!! Sweet!  ;D

Great work as usual Jeff!

Cheers,

Mike

 

[Echo North]

Awesome!  ;D

 

[rob61]

How are you powering the module when doing this alignment procedure out of the rack?

 

[jsteiger]

How are you powering the module when doing this alignment procedure out of the rack?

Robert, I have an edge connector on the module. It has 3' cables with XLR's for in and out. I have a little bench supply that I made that has banana connectors on it. I then connect to the PSU with three twisted wires that have alligator clips on each end. Some guys have built an extension of sorts with a blank L-bracket, a 51x proto card edge adapter and some wire.

You can kinda see most of it in the pic on page 3 of the CMRR PDF.

Best, Jeff

 

[rob61]

Can I take out all modules in the 51X rack, place one of these in the rack on the left side so I can get in there to adjust the screw, and send in (rack XLR in) with the cable you show in the docs with the resistors? Then take the XLR out (from the rack) to input back into the DAW?

 

[jsteiger]

Yeah you can do that. Maybe position the rack on it's left end in front of you, vertically. Add a little light so you can see. Yes, just connect to the XLR's to the rear of the rack. Should work out just fine.

 

[chunger]

Hey Jeff,

Just wrapping up a few preliminary items before jumping into the VC528 build. . . 51X rack and official PSU are now complete.  Cranked out a few of these. . .

. . . and I'm going to start wrapping my head around the VC528 starting soon!

 

[Snatchman]

Hey Jeff..Great looking product..!..Question: How will these work behind a line driver output..? I know they have great reviews following a mic pre ,but I'm wanting to try one behind my DIs ( Bass, guitar, Synths,etc.) with an active/variable balanced output line driver..Thanks.. 8)

 

[rob61]

My pair are finished and CMRR aligned. Now I'm experimenting with different DOAs. Are the two running in series or parallel? I'm wondering if it is beneficial to experiement running two different opamps for A1 and A2, or do they need to be matched?

 

[jsteiger]

Hey Jeff..Great looking product..!..Question: How will these work behind a line driver output..? I know they have great reviews following a mic pre ,but I'm wanting to try one behind my DIs ( Bass, guitar, Synths,etc.) with an active/variable balanced output line driver..Thanks.. 8)

They should work a treat. They have a 20k input Z so basically, any signal you would ever patch directly into a console...they will be very well matched for. In essence, they are a line input module.

My pair are finished and CMRR aligned. Now I'm experimenting with different DOAs. Are the two running in series or parallel? I'm wondering if it is beneficial to experiement running two different opamps for A1 and A2, or do they need to be matched?

Robert, the two DOA's are in completely separate parts of the circuit. A1 is the balanced receiver amp and A2 is the post fader booster amp. By all means experiment. As long as both amps will run on the voltage you have selected, you can mix and match to whatever works for the particular track/task at hand. Think more crayons. 

 

[dandeurloo]

Jeff, Love it!

 

[gar381]

Beautiful well done manual Jeff!!

GARY

 

[jsteiger]

Thanks guys. It would be even better if I had some 2623-1's.  :-[ :'(

 

[chunger]

jsteiger requested that I post here instead of starting a "newbie builds" thread, so here goes.  Hope it's not too boring for you experienced builders out there.  These photos are primarily for jsteiger to generate cleaner build documentation.  They are posted here for kicks and giggles as well as previewing.

So, before I start, a little "photo geeking" to figure out a decent look for the little subjects.  After a bit of tweaking and trying various setups, here's what I settled in on.

Here we go. . . it usually quite a while to fight through the excessively good packing, but once you finally peel out the goodies, here's what you should find in the kit.  Please note, my kit may vary from yours slightly because I went for a stereo pair which has closely matched resistor sets.  I have never known anyone to order 1 piece of bacon. . . that's absurd.  2+ is the only way too go  ;D

It all looks a bit daunting, but I figure everything is designed to go together in a very intuitive way, and breaking everything down into small, easy steps smooths the way.

Going by the preliminary build documents, the "discrete follower" sub-board should be assembled first.  It is contained in this baggie.

build document "1_DF.1-layout.pdf" identifies and locates all of the components.  I start by sorting the parts:

Note:  C1 is not used or included

Closeup of Q1 and Q2

Closeup of Q3

Closeup of C2

I set myself up on a vise to solder most of these components.

Populating. . .

To solder in the L header, I used a clamp which left 2 leads exposed.

And, component complete:

 

[jsteiger]

Looking good 'Chunger, as usual. I really like how you gave us the shot of your set up. Like a peak behind the scenes.  ;D

I know this is a few steps ahead but did you find the R and C pdf sorting sheets for the main PCB? Just making sure. 

Carry on.
Jeff

 

[chunger]

Next up, the relay board. . . details on components and placement are on "2_Plug-In-Relay.1-layout.pdf" in the support docs.

The relay board will be found in this baggie:

And, as usual, I sort and identify my electronic components first.

Careful about a couple of the diodes.  The markings are tiny. CR1 is marked like this:

CR2 and CR3 are like this:

and what the heck. . . Q1

Populating. . .

Again, I used a clamp to put the L-header on:

And, component complete:

 

[LHS]

Chunger! Love your work. Next level awesomeness


Hey Jeff--
Have you made progress implementing the new p + g faders yet? Any photos at this juncture?

 

[sunnen1]

;D keep those detail coming!

 

[jsteiger]

Chunger! Love your work. Next level awesomeness

I agree +1000 ;D

Have you made progress implementing the new p + g faders yet? Any photos at this juncture?

For this project or the console project? It would be so easy to use them this project but would need creative mounting other than a 500 series rack. No pics yet though as I am finishing another console related project first.