[BUILD] CAPI LC53A~500 Series~Love Child EQ Kit~Official Support Thread

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

jsteiger

Well-known member
White Market Member
Joined
Apr 11, 2008
Messages
3,506
Location
Nashville TN
Since the kits have started shipping, it's time for the support thread!  :)

**This is a semi complicated build. It is very important to read completely thru the Assembly Aid before starting on anything. There are some points made in the doc that can save you much time and prevent crucial errors during the build.

--------------------------------------------------------------------------------------------------------
September 21st, 2015 Update:
All support docs for this project can be found on the recently added
Support Docs page at www.capi-gear.com
--------------------------------------------------------------------------------------------------------


--------------------------------------------------------------------------------------------------------
March 5th, 2016 Update:
Rev B boards are now shipping for the LC53A. To easily identify, the Rev B boards are green and they have the CAPI® label affixed. The receiver circuit has been changed so that a CMRR adjustment is no longer needed. Besides that, most of the circuit is the same. To find out what else has been changed, please read the
Rev B Addendum. Like with all projects, it is crucially imperative that you follow the BOM that matches the revision of the PCB that you are building.
--------------------------------------------------------------------------------------------------------


Some details can be found here http://capi-gear.com/catalog/product_info.php?cPath=22_117_119_171&products_id=327

temp-LC53A.jpg


Cheers, Jeff
 
Here are a few pics to help point out some important things. They are not the best quality but will hopefully make their point until 'Chung can work his magic.

Click them to enlarge!!

This is the recommended LED bending.


This shows the standoffs and how the 2 boards fit together.


This shows the proper orientation of the Main-PCB to the steel bracket tabs.


In this pic you can see that none of the leads or solder joints protrude above the steel bracket.
 
Don't mind me.  I'm just getting situated here.

What's in the box?

p392300202-4.jpg


A little inventory to get the lay of the land.

p275290866-4.jpg


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

p507648283-4.jpg


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

p176024056-4.jpg


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

p39156324-5.jpg


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

p372732915-6.jpg


First, I place my resistors.

p348697146-4.jpg


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

p46356129-4.jpg


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

p454036862-4.jpg


p463974787-4.jpg


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.

p232676890-4.jpg


p8294120-4.jpg


Next, locate the opamp sockets for A1 and A2.

p150054991-4.jpg


Insert these from the back side of the PCB.

p288635638-4.jpg


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. 

p436883158-4.jpg


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.

p101428619-4.jpg


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.

p278235240-5.jpg


and, we're populating.

p137109370-4.jpg


p94524505-4.jpg


p215127405-4.jpg


p28048649-4.jpg


p177247580-4.jpg


p298172507-4.jpg


p245736386-4.jpg


p199154614-4.jpg


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

p534656703-4.jpg


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.

p769505055-4.jpg


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.

p76511216-4.jpg


p86133225-4.jpg


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

p402289108-4.jpg


p215602644-4.jpg


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

p487932866-4.jpg


p179785986-4.jpg


and the other end of the cable wired as normal

p529547005-4.jpg


My test cable complete.

p239449084-4.jpg


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. 

p924575928-4.jpg


p715567189-4.jpg


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 :p

p705744795-4.jpg


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.

p985281497-4.jpg


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.

p788110310-4.jpg


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.




 
OK. . . next we start in on the cut/boost PCB.

p635628880-4.jpg


First step is to locate and install the sockets for the CT05 and DF.2 opamps and discrete voltage followers.

p660213436-4.jpg


p784878447-4.jpg


These are installed and soldered from the TOP SIDE of the PCB.

p1008525867-4.jpg


It cannot be emphasized enough on this step.  Use sufficient heat to smoothly solder these sockets and most importantly. . . USE ONLY THE ABSOLUTE MINIMUM AMOUNT OF SOLDER TO SET THE PART!!! Remove heat and solder IMMEDIATELY when when the solder liquifies and the socket settles into the PCB.

p941819436-4.jpg


After soldering in these sockets, insert one of the cut-off leads from a large capacitor to break it in as it can be quite difficult the first time a pin is inserted into the socket. 

p1042197866-4.jpg


You may discover as I did on this step that solder can migrate very quickly under this socket and seize up the contact fingers making it impossible to seat a pin.  I fancy myself a rather smooth soldering iron pilot and seldom muck things up, but I managed to mangle 3 of these sockets (3 extras are luckily provided in the kit) by keeping heat on the joint too long and/or using too much solder.  The "C" or common terminals that are connected to the ground plane can be EXTREMELY difficult to remove if they are mucked up.  I found the only way I could remove them was to go from the back side of the PCB and fill the socket with hot solder and push it out the front side w/ the soldering iron.  I almost destroyed one of the pads, but eventually cleared the solder from the pad by using Hakko 808 de-soldering tool on the front side while simultaneously sticking my soldering iron into the pad from the back side.

p665679930-4.jpg


Rather exciting. . . the 2nd LC53A kit went together without any issues because I remembered to use the absolute minimum necessary amount of solder and keep the heat on only long enough to set the part.

p702701244-4.jpg


Next, I sort the resistors for the CB board.  There are a few :)

p248309516-5.jpg


And, place them on the PCB.

p204859590-4.jpg


Bend leads to hold the components in place, and solder from the back side.

p185512630-4.jpg


As recommended by jsteiger in the build manual, I purchased a CHP-170 cutter on Ebay for ~$6.00  It really does allow you to cut close to the PCB as required on this board to provide clearance for the metal frame.

p172541979-4.jpg


p282563083-4.jpg


resistors are populated.

p241357292-4.jpg


p315388504-4.jpg


One more view of closely-cut leads on the back side of the PCB using the CHP-170 cutters.

p363549862-4.jpg


Ok . . . resistors are done.  Now for capacitors.

p751037809-5.jpg


Note the marking conventions on the yellow polyester film caps.

p775250541-5.jpg


and, we're populating.  Ceramic caps first.

p987887904-4.jpg


Mind the polarity on the electrolytic caps.  Solid line indicates negative side.

p778650302-4.jpg


p721298170-4.jpg


p665494373-4.jpg


Next, locate the baggie with headers.

p616646718-4.jpg


And locate these parts.

p1001365093-4.jpg


And install J3 and J4

p916992307-4.jpg


p797683466-4.jpg


Use the 3M jumpers to set output load to "HiZ"

p1043244701-4.jpg


Next, locate the baggie with switches.

p905839254-4.jpg


And pull out SW1 which looks like this.

p720356956-4.jpg


and install. . .

p584746227-4.jpg


and trim leads tight to the PCB.

p997216596-4.jpg


Next, pull out 2 of the grayhill switches.  Make sure to pull the ones with single front pin (some have 2).

p764694457-4.jpg


And install SW4 and SW6

p910880397-4.jpg


I solder 1 pin only on each.

p977542702-4.jpg


p811501114-4.jpg


and verify that the grayhill is sitting flush to the PCB and the front face is perpendicular.

p1015471894-4.jpg


p956763559-4.jpg


Once everything is lined up, solder the remaining leads in and trim the leads tight to the PCB.

p721764093-4.jpg


 
Next, locate the baggie with stand-offs and mounting hardware.

p1019533399-4.jpg


and pull  3/8" screws and 1/8" standoffs.

p980823007-4.jpg


Intall screws on the back side of the CB PCB.

p1009879810-4.jpg


And standoffs on the front side.

p1055681260-4.jpg


Center these screws to the best of your ability in the solder pad on the PCB and tighten fully.

p742586320-5.jpg


Next, dig out the 7 pin header.

p1008479615-4.jpg


And place on the CB PCB.  important: DO NOT SOLDER THIS HEADER AT THIS TIME.

p883294867-4.jpg


Locate these bits:

p942494689-4.jpg


And assemble the main PCB to the CB PCB.

p750455333-4.jpg


Loosely install the long standoffs on the outside locations.

p772248990-4.jpg


p813947663-4.jpg


And the crush washer and nut in the middle location.

p977291409-4.jpg


Place the assembly on a flat, straight surface and set the length from the front of the PCB to the end of the connector pins at 5.87 inches.  I use my trusty dial calipers to make the measurement.

p696161996-4.jpg


It may take a few tries to get everything square and correct on the length, but when you have everything lined up, tighten down all of the nuts and standoffs to final torque which is as tight as you can go without breaking anything.

p322041775-4.jpg


Flip the assembly over, press the 7 pin header towards the main PCB and solder.  Pushing the header this direction makes it so you do not have to cut the pins after soldering as they will sit low enough to clear the metal chassis.

p324760576-4.jpg


And solder the 7 pin header on the main PCB side as well.

p342942352-4.jpg


Next find the baggie with pushbuttons and stickers.

p513328611-4.jpg


and pull the cap for SW1

p71003211-4.jpg


p186474999-4.jpg


Next we insert our assembled unit into the metal chassis.

p75025956-4.jpg


locate these 2 1/4" screws.

p396662626-4.jpg


and fasten the back side of the main PCB to the chassis after aligning and possibly tweaking the chassis to fit.

p530414049-5.jpg


temporarily place the faceplate.

p86937391-5.jpg


Align the faceplate with SW1

p534391347-4.jpg


and loosely secure the grayhill switches to the faceplate.  Here I am using some console tape over my socket to protect the faceplate from scratches.

p270083930-4.jpg


Align the faceplate center and dead parallel to the metal chassis so the gaps are even on both sides.

p501942741-4.jpg


p476320034-4.jpg


and tighten down the grayhill switches just firmly enough to temporarily hold.

Next, install the LED.  Note:  The short lead on the LED goes into the PCB hole that the arrow is pointing towards.

p527714405-4.jpg


The leads must be bent to align with the holes.  I also had to sand the ends of the LED with some 220 grit sandpaper because they were slightly too wide to fit into the PCB's holes.

p357643991-4.jpg


The LED will look something like this with a few 45 degree bends.

p63004196-4.jpg


Position the 1/2" clear pieces of shrink tubing on the LED's leads.

p220016770-4.jpg



And position the LED.

p512855102-4.jpg


Before soldering, grab an available Grayhill switch and insert.

p151618179-4.jpg


check to make sure the LED leads clear the grayhill switch and will not short to the switch's chassis.

p48054763-5.jpg


Once confirmed, solder the LED and cut the leads tight to the PCB.

p124250710-4.jpg


Next, I install the 2 toggle switches.  build manual says to solder only 1 leg of the switch at this time, but since the switch remains in position quite well from friction, I decided not to solder and wait until everything is installed in the chassis.

p497734691-4.jpg


p91652005-4.jpg


Next up is SW3 (grayhill switch).  Now that the LED has been installed and positioned, we can place this switch.

p343337051-4.jpg


Solder 1 pin to hold in place but still allow room for re-positioning.

p675669038-4.jpg


and make sure everything is tight to the PCB and straight.

p595644340-4.jpg


Solder the remaining pins and trim tight to the PCB.

p860530756-4.jpg


Next, locate these header sockets.  It's important to install these on the CB PCB and not the other way around.  If installed on the wrong PCB, they will not fit into the chassis.

p788602099-4.jpg


p1015818686-4.jpg


p895918286-4.jpg


Make sure these sockets are vertical and tight to the PCB.

p904826392-4.jpg


 
Next, install the output transformer.  Locate the baggie with the transformer mounting hardware.

p605518516-4.jpg


and locate these parts.

p898828763-4.jpg


p710320315-4.jpg


Install flat washers to the 2 long screws.

p719587901-4.jpg


And insert into the transformer from the top side.

p678657628-4.jpg


While holding the 2 screws in place with your fingers, install 2 additional flat washers on the bottom side of the transformer.

p1053170150-4.jpg


And place the assembly onto the PCB maintaining the flat washer between the transformer and the PCB.

p817819571-4.jpg


Add lock washers on the bottom of the PCB.

p708875560-4.jpg


Install nuts.

p785305817-4.jpg


Tighten with a screwdriver on the front side after verifying the transformer is aligned with the marked box on the PCB.

p590505272-5.jpg


Cut, strip and tin the leads 1 or two at a time making sure not to cut too short.

p888160678-4.jpg


I use small pieces of head shrink tubing to organize the wires as I install them into the PCB according to the marked colors.

p554358973-4.jpg


p742447526-4.jpg


And, transformer is installed.

p599164857-4.jpg


Next, refer to the provided document for CB PCB Grayhill switch stop pin positions and insert the appropriate pins into the 3 grayhill switches.

p226664026-4.jpg


They should look something like this.  Careful with these.  Drop one on the floor and it may just dissipate into the ether and never be found again.

p467403515-4.jpg


And install the silver stickers to retain the pins.

p299382269-4.jpg


Next, I move to the DF.2 discrete follower boards.

p268443878-4.jpg


p516473304-4.jpg


Sort the electronic components.

p285374901-5.jpg


This is my chosen method for installing the pins into the PCB.  (NOTE: This procedure deviates from the recommended build order in the assembly manual)  This is just he way I've grown accustomed to installing opamp pins and I did not feel comfortable risking a solder leak onto the side of the pin that would contact the socket on the PCB for fear of sticking everything together inadvertently.  Jsteiger may very well have much steadier hands and perhaps a finer soldering tip than I am using.

At any rate, I insert pins into the PCB first.

p500766973-4.jpg


Then, place the discrete follower PCB onto the pins and solder.

p143201968-4.jpg


p155458277-4.jpg


p246694981-4.jpg


I am using the recommended component bending method in the build manual using my smallest screwdriver as a bending tool.

p431619405-4.jpg


Populating. . . (Note: I deviated from the instructions again in the following sequence because I usually don't like shoving the resistors all the way into the PCB because I like to have a little solder flow onto the top side of the PCB if possible.  Due to clearance issues, I recommend putting theses resistors as low as possible into the PCB as described in the assembly aid document.  The clearances are VERY tight and the final height of the large, yellow capacitors on the LC-EP PCB are unpredictable.  Every thousandth of an inch here helps, so please push the resistors all the way into the PCB.  The build was successful, but I believe I had contact between a capacitor and one of my opamp resistors and had to go back in and jam the capacitor in further to clear.)

p454537242-4.jpg


p346241468-4.jpg


p230228276-4.jpg


Discrete followers complete.

p508539272-4.jpg


p469805017-4.jpg


Next, I buid the 2 DTO5 discrete opamps.

p303950084-4.jpg


Components sorted:

p67985451-5.jpg


I use the same method to install the opamp pins.

p336915836-4.jpg


p98665565-4.jpg


And populate. . .

p417730190-4.jpg


careful with the diodes.  Make sure the end with the line corresponds to the direction of the printed arrow on the PCB.

p288653219-4.jpg


p108099149-4.jpg


p110733393-4.jpg


Again, watch out for the orientation of the diodes.

p519633034-4.jpg


And the opamp is complete.

p72396267-4.jpg


p14408886-4.jpg


Next, build one more DTO5 discrete opamp.  I did them one at a time because they have a pair of matched transistors that I did not want to get mixed up between the baggies.  If building together, just remember to keep these HFE matched transistors paired together.

Both DTO5's complete.

p117358598-4.jpg


All CB PCB amps ready to install.

p386985698-4.jpg


p241061330-4.jpg


Main PCB and CB PCB complete. . . except for soldering a couple of switches to be complete with faceplate installed.

p139742049-4.jpg




 
Next, we do what will hopefully be the final installation of the PCB assembly into the metal chassis.

p539606970-4.jpg


We will use lock washers now to secure the back of the PCB.  Make sure to push the PCB assemble all the way against the front of the metal bracket.

p908143714-4.jpg


p897884735-4.jpg


Next, re-install the faceplate.

p642522021-4.jpg


and install the supplied nuts.  Do not use the lock washers that came with the Grayhill switches.

p1053418044-4.jpg


This is a temporary placement, so we do not need to crank these down, but we want to align the faceplate so that the gaps on the top and bottom are dead even again.

p780811807-4.jpg


At this point, solder in the remaining switches on the CB PCB.

p601737322-4.jpg


And trim the leads tight to the PCB.

p818393130-4.jpg


Voila!

p710724197-4.jpg


p844457996-4.jpg


At this point, we are ready to test and see if the unit passes signal.  Here's I'm setting up to input 1K sine at 4dBu.

p640821063-4.jpg


p615750798-4.jpg


And, the output waveform looks good and the level matches at least as far as my meter can tell, so everything appears to be working on this build!

p569456308-4.jpg


Onward to the LC-EP PCB.

p636907073-4.jpg


First sort resistors and transistors.

p1039145167-5.jpg


And populate the flat-lying resistors first.

p560377144-5.jpg


Then move to the free-standing resistors around the grayhill switch.  This is how I set up to solder these in.

p1057562536-4.jpg


p676609890-4.jpg


And resistors are populated.

p976594192-4.jpg


Next, install the 5 transistors.

p77939573-4.jpg


And, we're sorting capacitors.

p442494690-4.jpg


And, populating capacitors. . .metalized polymer ones here.

p533568081-4.jpg


p16383471-4.jpg


Polystyrene caps go in.

p231226253-4.jpg


And polyester film caps next.  Some of these may need to be jammed pretty hard into the PCB as here is very little clearance available in the sandwich.  Check and adjust as needed.

p190772144-4.jpg


p508522394-4.jpg


One lonely electrolytic cap.  Watch the polarity on this one.

p296412119-4.jpg


Next, install the inductors.

p210910143-4.jpg


Note the dot on the sticker as well as the diagonal corner at the base indicating the "COM" pin which is labeled and has a square-shaped pad on the PCB.

p27454991-5.jpg


p226813349-4.jpg


Solder in the inductors and cut the leads tight to the PCB.

p533587719-4.jpg


Inductors populated.

p177341368-4.jpg


Next we install grayhill switches.

p272753006-4.jpg


p96304078-4.jpg


Solder one pin and check alignment.

p473850002-4.jpg


p446751552-4.jpg


p245940127-4.jpg


After confirming perpendicular to the PCB as well as sitting tight to the PCB, solder and trim the leads tight.

p127038420-4.jpg


Next, install toggle switches.

p468645766-4.jpg


p105276487-4.jpg


Only solder the middle rear pin on these at this time.  We need a little wiggle room to place the faceplate later.

p410662106-4.jpg


Next, locate these long jumpers and install.

p9924404-4.jpg


p415742291-4.jpg


p62321377-4.jpg


I solder one pin and then adjust to get them as straight as possible.

p28364168-4.jpg


 
Install stop pins on the Grayhill switches next (refer to the proper document and confirm 12:00 and 5:00 placement.

p156900234-4.jpg


They should look something like this when installed.

p291913271-4.jpg


And, apply stickers to retain the stop pins.

p344256643-4.jpg


LC-EP PCB complete.

p501446411-4.jpg


p365509062-5.jpg


Next, remove the faceplate from the chassis and insert the LC-EP PCB straight down into the chassis while aligning the 2 long jumpers.  Verify proper seating from the strategically placed vent holes in the chassis.

p359774232-4.jpg


And install the faceplate.

p19614295-4.jpg


Carefully align the faceplate so the gaps are equal on the top and bottom sides of the chassis and parallel to the chassis.  Then,  install and tighten down the all of the grayhill switch nuts.

p323103368-4.jpg


p439003302-4.jpg


p152217202-4.jpg


With the faceplate aligned, solder in the 2 remaining toggle switches.

p35584278-4.jpg


And trim the leads tight to the PCB.

p58955183-4.jpg


Locate these 2 flat head screws.

p514131147-4.jpg


And secure the EP-LP PCB to the chassis.

p310319174-5.jpg


The EQ is now electronically complete.

p2038010-5.jpg


p438880886-4.jpg


Verify with a straight edge that there are no component leads or solder blobs protruding above the chassis on both sides of the unit.

p274472368-4.jpg


Locate the remaining small screws.

p446175346-4.jpg


And install the metal covers.

p7075175-5.jpg


p98351416-5.jpg


p123455887-4.jpg


using pliers, rotate all of the grayhill switches to the 3:00 position.

p345877561-5.jpg


And locate the knobs.

p312262468-4.jpg


frequency selection knobs should be installed first because of this clearance issue.

p151553607-5.jpg


p247554430-5.jpg


Install the cut/boost knobs and locate color coded stickers.

p73469162-4.jpg


Install blue stickers on the frequency select knobs and grey stickers on the cut/boost knobs.

p72668499-4.jpg


and the build is complete!

p442542238-5.jpg


Humans win!
 
anyone having trouble soldering the milmax recepticals into the main board? specifically the "C" one? in both DOA positions i had one hell of a time trying to get solder in there... almost like a giant heatsink on there. Tips?

-pete

(adding)...
same deal with the super little ones for the DVF and the other DTO5s .. the "c" is impossible to solder... is this because these pads are part of the ground plane which takes up a lot of metal on the pcb, sinking most of the iron's heat? should i jack up the heat for these pads? something > 600deg F?
 
Yes indeed that is why. A special note for these is in my nearly finished Assembly Aid document. The C is the hardest to solder and it is because they connect to the ground plane. What temp are you running? I am usually around 740F or so. I have done numerous builds and while not easy, they are always doable. Maybe try tinning the top of the pad without the socket in place. After it cools, drop the socket in and reheat while applying a little bit of solder. One thing to also watch for is the socket sticking to your iron tip when you remove the iron. I try to pull away horizontally, never vertically.

While we are on the subject, one can only solder from the top with these little sockets, never the bottom.
 
ahh... yes- i'm doing EVERYTHING at 550ish... too low? are you saying you solder everything in this build up in the 700 range? or just the "c" pads?

another question...

in my other builds (vp25s) i inserted the DOA mil max sockets on the top of the PCB and soldered them from the top (the same way you do these little sockets...) this worked fine and the units are all good (and sounding wonderful)... i did the same for the main board of the lc53a here.. and a DOA fits fine, but i'm realizing that there's a lot less room in the enclosure and these may "stand" too high off the pcb... so  jeff... do you think this will be a problem ??

thanks!!

-pete
 
I am always at that temp and never change it.

You should be fine with the sockets for the 2520's the way you have them. The opamps should still sit far below the 2503 right? I would guess yes so no worries.
 
quick update: bumping up to 700-ish deg. makes the ground plane related soldering much much easier. thanks jeff!

-pete
 
I have added the just completed LC53A Assembly Aid link to the first post of this thread. Please check it out and let me know if anyone finds any silly errors.

BOM's for the larger PCB's are coming in a few minutes.

Thanks for being patient guys!  ;)
 
Links for all of the BOM's and build docs have been added to the first post of this thread. Currently, the only thing I am missing are the docs for the DF.2 and DTO5 PCB's. Will try to get those completed ASAP. I think the above will buy me 16-20 working hours though! :D
 
For the Milmax DOA sockets I first use a flux pen on the pads, top and bottom.  Then I pre-cut six pieces of solder to the same length, then I solder each pin with one piece of solder each, at 750º.  Be sure to heat the pad and socket and not pull out the socket when you remove your iron.  The length of your solder pieces will vary, I use a piece long enough to give me a nice concave volcano, by using the same amount of solder on each one you get a nice consistent look from the top.

I solder the sockets first and use non-noclean solder, clean the board thoroughly, then stuff the rest.
 
Alrighty folks, the DF.2 and DTO5 build guides and BOM's have been added to the first post. That should cover it for build docs. Everything is now complete.

Happy soldering!  8)
 
jsteiger said:
Alrighty folks, the DF.2 and DTO5 build guides and BOM's have been added to the first post. That should cover it for build docs. Everything is now complete.

Happy soldering!  8)
Awesome support,a great work you´re doing,I owe you one in advance.
Looking forward to receive my ordered (and paid ;D) pair,I´m sure I´ll love them.

Best regards from munich,germany,

Udo.
 
Hey guys

I added a few pics to the 2nd post of this thread. They point out a few important things.

I forgot to do the board overlays so guess I am not finished after all!

Cheers, Jeff
 
Can't find my precision resistors, so can I complete the build and then do the CMRR alignment once its all assembled?
 

Latest posts

Back
Top