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

[johnny dance]

Hey jeff,

I am using 2 red dots (both burnt in) from the 2 25's I built up the rack and cabling seem to be ok too...

 

[jsteiger]

OK. I will post a few "block" test spots so you can narrow down where the problem is at. I am packing orders now so in a few hours.

Best, Jeff

 

[jsteiger]

Johnny, I have put together a little pdf for this occasion. Hopefully these Troubleshooting Tips will help.

Let me know how you do.

BTW, I have added this link to the bottom of the first post of this thread too.

Cheers, Jeff

 

[chunger]

onward!

Let's dig up the rest of the caps for the main PCB

Identifying parts again:

C6 27 pF

C5 82pF

C29 47pF

Watch the polarity of the electrolytics.  The "-" side is indicated with a solid stripe.

And, sidenote here, I managed to melt C20 when I attempted to touch up a solder joint on the front side of the PCB. . . trying to make all perfect solder joints for pictures. . . oh well.  Jeff has been contacted for a replacement WIMA.  In the meantime, since I have 2 kits for a stereo pair, I went ahead and replaced C20 w/ one from the other kit, and the build goes on!

Caps installed.

Next, I place the trimmer pot RV1

And SW1

Next, I install the millimax pins for the DOA's.  They are found in this baggie. . . watch out.  These little critters like to run away, and I once spent an hour looking for one on the ground from a VP26 build.

Insert these from the back side of the PCB.

And, solder from the back side.  I set my iron a bit hotter and made sure to flow a proper amount of solder to make these solid as some op amps need to be pressed in pretty hard to seat, and I like these sockets to have a solid mechanical connection to the PCB.

And, this is how they look from the front side after getting soldered in.

And, the main PCB is populated.  Humans win.

 

[chunger]

Next up, I install my 3 pin headers for configuring the VC528.  These headers and jumpers are found in this bag:

This will need to be cut into 5 separate 3 pin units.

And installed in these locations taking precaution to stand them up perpendicular to the PCB.

For the next step, I will need my grayhill switches found in this baggie:

And use these installed from the front side to align my faceplate to the L-bracket.

This will facilitate lining up the mini toggle switches SW3 and SW4

Holding the switches firmly in place, solder the center lug only.

Next, locate the PCB mounting hardware.

Install standoffs and screws as as pictured below.

Making sure to leave the front 2 standoffs loose so the screw does not protrude over the top of the standoff.

Then, carefully slide the PCB into position.

And secure the nuts (without lock washers for now).

Confirm proper seating of the mini-toggle switches as well as the PCB being precisely aligned with the L-bracket.

And solder the remaining lugs on the mini-toggle switches with the unit assembled.

 

[chunger]

Next, I take a close look at the Grayhill switches. . . this particular kit is an early-run kit, and the position stops on the Grayhill switches are pre-installed.  Later versions of the kit will require placing the stop pins as they will utilize a more universal setup on these switches.

It is important to position these switches perpendicular to the PCB, and to facilitate this, jsteiger recommends starting with the inner switch, soldering 2 outer rear lugs first, verifying component alignment, and then soldering the front 2 lugs.

Then, proceed to the outer switch and repeat

After all is aligned, carefully solder all of the remaining lugs.  Check for solder bridges as these are pretty narrowly spaced.

 

[chunger]

Next up are the 2623-1 transformers.

Locate the mounting hardware.

The component sequence for installation is as follows:  Screw, flat washer, transformer, flat washer, PCB, lock washer, nut.

And, transformers are positioned on the PCB.

Use short segments of shrink wrap to consolidate the wires and solder to the appropriate locations on the PCB keeping the wire runs short.  Be sure to route the wires well clear of the op-amp location.

Next, I install the relay sub-board.  Make sure the relay board does not short out against the transformer.

. . .and the discrete follower sub-board. 

And, this is where I stopped tonight.

The attention put into the design of this kit is pretty phenomenal so far.  I'm looking forward to getting this up and running!

 

[Ptownkid]

wow man, you are great at this!

 

[jsteiger]

wow man, you are great at this!

Yes 'Chung. I was thinking the same exact thing when I went thru the pics this morning. You really make this project look great. Heck, I am thinking of building one.  ;D 

BTW, I have 2 more projects nearing completion. So, reserve some more time for me this winter. 

Best, Jeff

 

[Grummy77]

Can't wait to see what they'll be!       

 

[chunger]

Yes 'Chung. I was thinking the same exact thing when I went thru the pics this morning. You really make this project look great. Heck, I am thinking of building one.  ;D 

BTW, I have 2 more projects nearing completion. So, reserve some more time for me this winter. 

Best, Jeff

Careful. . . audio crack dealers shouldn't dip into their own stash   Bad for business.

Just an observation, the GDIY 51x crew (jsteiger, silent:arts, and others) are putting out some really awesome products.  From my limited exposure to DIY, I think these kits are really top-shelf and the professionalism displayed on all fronts (design, manufacture, sale, and support) set the bar high.  I do my best to raise the bar on documentation to de-mystify these projects a little and draw in some fence-sitters. . . and hopefully let people have a glimpse of how much fun these builds are!

 

[dissonantstring]

hi chunger,
great stuff!  looking forward to your thoughts on the build as well with regards to sound and use.
btw, sorry for the OT, but what kind of camera are you using for your documentation?
best,
grant

 

[baadc0de]

btw, sorry for the OT, but what kind of camera are you using for your documentation?

Canon EOS DIGITAL REBEL XTi alias 400d ?

 

[chunger]

btw, sorry for the OT, but what kind of camera are you using for your documentation?

Canon EOS DIGITAL REBEL XTi alias 400d ?

Someone's been reading the metadata on the photos    This is the build thread, so I won't clutter up the works too much, but everything I know about lighting, I learned from here:

http://www.strobist.com

David Hobby and strobist are the DIY or photographic lighting.

Entry level DSLR's can perform great when you hit the sensors with the right quality and quantity of light.  I'm shooting 1/200 sec, iso 200,  in the f10-16 range on decent glass (Canon 17-55 f2.8 ), so I'm maximizing each available pixel (nowhere near the outer fringes of the performance envelope of my equipment).  It's akin to setting up your gain stages right on a good, strong signal source, through the right mic, and hitting tape optimally.  The trick for me is not the camera. . . it's the light.  Sortof like recording in an optimally tuned room with adequate equipment. . . much more forgiving and responsive than recording in a horrible room with highest grade equipment.  Yes, for higher-profile gigs, I would certainly rent better camera and glass, but for the projected end-use of this photo set, I can generate high enough quality images w/ my ghetto rig because  I know it's capabilities and limitations.

 

[jsteiger]

hi chunger,
great stuff!  looking forward to your thoughts on the build as well with regards to sound and use.

Grant

Check out Today Is Your Day, (Shania's latest single) if you want to know what they sound like. http://www.youtube.com/watch?v=OMciyWyugKY&ob=av2e I believe Reid had them strapped across the mix bus. I am waiting for clarification from him right now. I do know he fell in love (with the ML's!) and now has his own pair. I did a little mod for hard bypass in place of the Mute for him.

Cheers, Jeff

Edit: Reid confirms the ML's were on the mix bus.

 

[chunger]

OK. . . last push.  I took a moment to pause because the following assembly steps were complex and I wanted to make sure everything was clear in my mind before melting stuff together.  After reading the instruction set through a few times, I determined that hilarity would probably ensue especially trying to photograph some of these steps by myself 

OK. . . next grayhill switch.  This is the trim attenuator.

Make sure you don't lose those 2 barely visible pins.  We need to insert one between "1" and "12"

. . . and another between "8" and "7"

It'll look something like this from the bird's eye view.

Next, install the stop retainer seal "sticker".  Make sure the retainer does not sit on top of the raised center portion.

Next, we temporarily place the switch on the the sub-board without soldering.

We are checking for resistors shorting against the switch's outer metal casing.  The gaps are narrow.

Having established the components do not interfere, we align the L-bracket to the faceplate again and secure with a clamp.  Align the hole reveals as perfectly as possible here.

Place the spacer washer on the grayhill switch.

And insert the LED.  The small cathode end of the LED should go in the hole the arrow is pointing to.

 

[chunger]

Next, plosition the sub-board (w/ loose grayhill switch and loose LED) and lightly install the nuts.

Fiddle with positioning until the board is perpendicular to the L-bracket and all spaces look even and correct.

According to the instructions, there should be a .410" gap between the L-bracket and the sub-board.

After verifying everything is properly positioned, I tightened the nuts just snug.

Next, push the LED into the faceplate.

This should protrude slightly in the front.  Solder the LED in, and trim the leads.

Then, double check alignment and gaps again, and solder the grayhill switch.

 

[chunger]

Next, locate the 2 L-headers.  There should be a long one and a shorter one.

Place the long one on the back side of the main PCB at J1-3.

Because we're getting close to that part with the hilarity, I used a little tape to keep this from falling out.

Next, place the shorter L-header on the backside of the main fader sub-board.

Ok. . . here's the hilarious part.  This was an unbelievably difficult set of pictures to get

Whew. . . all components are in position.

Next,  re-attach the main PCB to the L-bracket.

And, secure the nuts on the front faceplate.  Make sure the main fader sub-board is pressed firmly against the main PCB.

Check component alignment all around to make sure the sub-boards are perpendicular.  It doesn't hurt to be very careful at this stage as a mis-step here could cost a lot of time and effort to undo.

Next, I begin soldering the L-headers.

Next,  solder from the bottom of the PCB the near lead on the L-brackets.  The rest can be completed at a later step.

And, soldered in.

Next, insert leads saved from the large capacitors into these slots.

And solder securely from both sides to make sure there is a solid mechanical connection.

Next, disassemble the unit again, and solder in the L-header leads that were inaccessible in previous steps.

Utilizing a cut-off from one of the transformers, create a ground wire between the trim-switch sub-board and the main PCB.

 

[chunger]

Electronic assembly is complete at this stage. . . next, re-assemble the main PCB to the L-bracket and the faceplate again.

Oh, don't forget about the little spacer on the grayhill trim switch.

This time, upon re-assembly, apply lock washers to the standoffs.

Nuts go on finger tight first. . .and then, using console tape on your sockets to protect the faceplate markings, and snug down the switch nuts with the protected tool.

Poof!

 

[chunger]

Next, locate the baggies with the knobs.

First, install the HPF knob.  Use pliers to turn the switch to the 12Hz position and tighten down the knob.  This one should be pretty straight forward.

Next, install the LPF knob.  This one will be a little trickier because one of the allen screws tightens against the flat portion of the shaft.  No problem. . . position the shaft with pliers to 18Khz position.  align the knob to point towards the "1" of "18" marking and tighten the allen screw that does not land on the flat portion of the shaft.  Then, as the other screw is tightened, the knob will migrate towards center.

Position the trim twitch shaft to -3db and attach that knob as well.

Next, locate the main fader to 0db by observing the copper contact point in the clear window of the switch, and secure the main fader knob.

Sticker time. . .

Next, I take a look at the documentation and decide how I want to configure the 5 jumpers.  J6 activates an unbalanced output to pin 3 on the edge connector for a future application.  I set that to "NC".

J5-1, J4-3, and J3-3 determine if the discrete receiver stage is inline or bypassed.  I opt for "D" or inline.  J8-1 is the DC-link option to activate mute logic on pin 6 of the edge connector.  I set that to "N" or not-linked since that's how jsteiger ships these stock.

Next, I hook the unit up without opamps installed and see if I read the correct voltages to the op-amps.

All voltages read normal in +-16V as well as +-24V modes.

The red tape indicates this is my bricked GAR2520. . . I haven't been able to figure out what's wrong with it, but it's the first op-amp that goes into every one of my builds because the sockets are bloody stiff the first time pins are inserted, and inevitably, I bend pins or need to apply a lot of pressure to seat the op amp the first time.  So, I beat up on my bricked op-amp.

After I insert and remove the bricked op-amp a few times in both sockets, I install a pair of fully functional GAR2520's and make sure to set my voltage to 16V!

And, there we are. . . assembly is complete on the VC528. . . Humans win!

I'm going to go to sleep now.  .  .Thanks, bye.