jsteiger

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #320 on: February 23, 2015, 01:36:08 PM »
Bad solder joint somewhere is my guess.
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Tschem

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #321 on: February 24, 2015, 04:40:06 PM »
tripple-checked everything now, every resistor, diode, capacitor, the transformer, DVFs, DOAs, every solder joint...even put more solder on the DOA sockets...measured possible connections of solder joints, re-calibrated CMRR...can't find nothing.

any more ideas?

jsteiger

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #322 on: February 24, 2015, 09:25:20 PM »
If the level keeps changing, there must be some intermittent problem somewhere on the build.
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PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #323 on: March 01, 2015, 05:50:33 PM »
Grayhill stop pins - yes, I lost one, arg.  Can I use a very stout piece of wire lead from a component in place of the stop pin?
« Last Edit: March 01, 2015, 06:05:00 PM by PeteJE »

jsteiger

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #324 on: March 01, 2015, 05:55:54 PM »
Grayhill stop pins - yes, I lost one, arg.  Can I use a very stout piece of wire lead from a component it place of the stop pin?
Yes indeed. A short piece of resistor lead will work a treat.
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PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #325 on: March 03, 2015, 04:26:32 PM »
Silly newbie question....  I got to the first unity gain test before final assembly.  When first put up, the output was loaded down and the unit was humming.  I swapped out the A2 (output?)  gar 1731 op amp to a different one (ML2520) and all was fine - simple, bad op amp (both kit built).

Now, just for grins,  I put back that first op amp again (gar 1731) and the original issue cleared up and unity gain good with no hum.   

Why would this happen - it seemed seated fully first time - maybe components touching, seating exercised??  not sure.  Hoping not another coincidental issues or really just some A2 op amp issue on that first try?

jsteiger

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PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #327 on: March 03, 2015, 10:29:28 PM »
Are they fully seated? http://classicapi.com/catalog/DOA_Install.php
Thanks for the link, Jeff.  That is all I can imagine, maybe not fully seated at first, then swapping back and forth fixed this issue and brought it to working condition.   

I guess I ask because, if not fully seated A2 are possible symptoms a loaded down or reduced output and hum (not clean, more like harmonics - a humming buzz)?     


PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #328 on: March 04, 2015, 12:32:45 AM »
Oh boy, oh boy, oh boy......  chunger, TY for the excellent build pictorial, getting to those two sweet words is awesome - humans win!
Final test tomorrow.....

« Last Edit: March 04, 2015, 01:55:46 PM by PeteJE »

PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #329 on: March 05, 2015, 12:15:05 PM »
It works!  Sounds incredible,  so smooth, musical, no odd nodes or resonances,  just perfect!  Thanks Jeff for your help along the way and Chunger for making this possible for me to do (I call it adult legos - because your guide is so good).   I currently have gar2520 in A1 and gar1731 in A2 - I would be curious to know any differences to be expected with both 2520 or both 1731 or any other op amp preferences/experiences.

I have one BIG problem.... I need a second one ASAP, and the store is out for now, ;) - I'll keep checking stock.  (also kind of excited for the FC526 too).


« Last Edit: March 05, 2015, 12:21:25 PM by PeteJE »


kante1603

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #330 on: March 05, 2015, 03:46:25 PM »
I have one BIG problem.... I need a second one ASAP, and the store is out for now, ;) - I'll keep checking stock.  (also kind of excited for the FC526 too).
Congrats,you can sell your 480 or 300 to gain a lot of money for several lovechildren (that's a LARC on the right side in the pic,no?) ;D .......but only if you have a spare one,hahaha!
Did you experience that the LC53 adds fantastic "sound" even when in bypass ;) ?
I have them inserted just for that in a lot of scenarios (on a stereobus to get rid of "digital sound" we have to deal with nowadays)!


Have fun,


Udo.


(Edited typo)
« Last Edit: March 07, 2015, 05:33:14 PM by kante1603 »

PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #331 on: March 05, 2015, 04:48:33 PM »
I have one BIG problem.... I need a second one ASAP, and the store is out for now, ;) - I'll keep checking stock.  (also kind of excited for the FC526 too).
Congrats,you can sell your 480 or 300 to gain a lot of money for several lovechildren (that's a LARC on the right side in the pic,no?) ;D .......but only if you have a spare one,hahaha!
Did you experience that the LC53 adds fantastic "sound" even when in bypass ;) ?
I have them inserted just for that in a lot of scenarios (on a stereobus to grid rid of "digital sound" we have to deal with nowadays)!


Have fun,


Udo.

Ha!  It is a 480L.  On that note, although I like them very much, the JLMs may get "traded in" for the FC526.........  we'll see. 

kante1603

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #332 on: March 05, 2015, 05:05:09 PM »
Ha!  It is a 480L.  On that note, although I like them very much, the JLMs may get "traded in" for the FC526.........  we'll see.
Don't do that!
Use them in a chain,I do it all the time to get the mostt "bombastic" Rock-Vocals ever:1176(F76 in my case) to catch just the transients,then into optocomp (LA500s in my case too) to make it "powerfull".Maybe do the slow-attack-mod.


Very curious for Jeff's take on the FC576 btw.!


Best,


Udo.

Tschem

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #333 on: March 07, 2015, 04:35:53 PM »
just wanted to add that the issue with different I/O levels is solved. the problem was a solder joint of a resistor leg, which looked perfectly soldered from the backside of the pcb but apperently wasn't. so no chance to see it, it was solved more or less incidentally. nonetheless, thx for the support!

jaminem

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #334 on: March 08, 2015, 11:01:29 AM »
Hi all, new to this forum - thanks for having me.

Big fan of Jeff's kits and have built several pre-amps now building this EQ.

The CMRR calibration has me stumped.
I got the test jig to make this easier, but to be fair I'm pretty clueless (I play bass)...

I'm out putting a 100hz sine wave from my DAW to my 500 rack.

have the card plugged in, to the rack and the main pcb, put a DMM on as chungers build suggested but got nothing from C to the negative of the large blue cap? I get something from V+?

Can I measure what ever it is i'm supposed to be measuring back at my DAW?

Totally no idea, and the CMRR doc and chungers build don't use the jig, so not even sure how this works?

help!

jsteiger

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #335 on: March 08, 2015, 11:08:47 AM »
You must engage the pushbutton switch on the Extension Jig's PCB to do the CMRR adjustment. You are trying to measure the output of the first amp stage. If you are using a DMM you must set the meter to ACV. Do you have an opamp in position A1?
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CAPI is not affiliated with, endorsed by, or sponsored by API.

jaminem

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #336 on: March 08, 2015, 11:33:39 AM »
Hi Jeff, switch engaged, multimeter on ACV - mine has options for 750 or 200? im using 200? pre built 2520 on opamp A1.

red DMM lead on c, black on - leg of big blue cap?

Got nothing?

oddly I get a reading when the switch is off?

jsteiger

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #337 on: March 08, 2015, 11:43:05 AM »
I would imagine that its a DMM thing. It may be better for you to try an monitor this level thru your DAW. You will need to rig up and unbalanced cable with the signal coming from the same cap location that you had the red probe hooked to.
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CAPI is not affiliated with, endorsed by, or sponsored by API.

PeteJE

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #338 on: March 09, 2015, 12:07:55 AM »
Hi all, new to this forum - thanks for having me.

Big fan of Jeff's kits and have built several pre-amps now building this EQ.

The CMRR calibration has me stumped.
I got the test jig to make this easier, but to be fair I'm pretty clueless (I play bass)...

I'm out putting a 100hz sine wave from my DAW to my 500 rack.

have the card plugged in, to the rack and the main pcb, put a DMM on as chungers build suggested but got nothing from C to the negative of the large blue cap? I get something from V+?

Can I measure what ever it is i'm supposed to be measuring back at my DAW?

Totally no idea, and the CMRR doc and chungers build don't use the jig, so not even sure how this works?

help!

Not sure if helpful but I can share how I did mine.  I used a protools channel on input, sent the unbalanced signal back to this input with some alligator clips using a TT to XLR (XLR back into protools from my snake, and using a tt to xlr because the tt is easy to clip onto with the clips from the unit).  I have a plug in that reads pretty sensitive and instantaneous dbu (avid pro limiter) and this made it easy to see and verify the low point of the trim pot.  I did use 400hz as in the instructions, not sure if 1k would be better (since I wasn't really dealing with a DMM), but my unit ended up quiet and clean.  This was using Jeff's extension jig for connection to the rack and input to the unit (with the button in and led lit on the extension jig). 
« Last Edit: March 09, 2015, 12:12:18 AM by PeteJE »

jaminem

Re: [BUILD] LC53A~500 Series~Love Child EQ Kit~Official Support Thread
« Reply #339 on: March 09, 2015, 04:18:36 AM »
Thanks guys, I'll knock up an unbalanced cable and see how it goes  :D


 

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