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Project Specific Discussions => Filters/Equalizers => Topic started by: jsteiger on October 03, 2016, 07:32:45 PM

Title: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 03, 2016, 07:32:45 PM
Hey folks

I have  finally just released my 2 new rotary graphic equalizer kits, the LC25 and the LC40.

Details and automated checkout can be had here:
http://capi-gear.com/catalog/index.php?cPath=22_117_119_212

I have changed the way the support docs and build pics are presented. Instead of cluttering up this thread with a zillion pics, I have them posted at my site along with detailed instructions. Chunger has just become too busy so he graciously advised me on photography equipment and technique so the pics are by yours truly. They will never compare but hopefully will be good enough! The build pictorial can be found here:
http://capi-gear.com/catalog/Build_LC25-40_Rev_A.php

Since this is the official support thread, please post all questions, components and/or build problems here. I will do my best to help you get things sorted.

And heres a pic of the lovelies:
(http://www.capi-gear.com/catalog/images/gallery/LC25-LC40/both-front.jpg)

Cheers, Jeff
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: brewbacca on October 04, 2016, 04:46:21 PM
Yay! They're out!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on October 07, 2016, 08:05:27 PM
Awesome looking  eq's congrats Jeff!

Well I suppose I'll kick this beast off. Took my time installing and upon firing up ( with a red dot op amp) I'm getting a loud  humming. Passing audio, no pk led lighting however, it appears as though the Eq filter's seems to function as I adjust frequency control with the knobs.

Puzzled, I turned it off shortly there after as to no damage anything.

Taking it back apart- I've double checked to make sure no leads are touching eachother or the metal on both the switch PCB and the main Pcb.

EDIT: TURNS OUT IT WAS THE 3 SLOT SNACK BOX.

Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 08, 2016, 09:43:39 AM
.....I have  noticed a discrepancy in the photo layout of the BTo5 photo guide as the arrows for the diodes go in the opposite directions, however it looks like  that's a different "prototype" pcb as the silkscreen shows it going that way too.
Not sure what this means exactly. The DTO5 board shown in the photos is a Rev B and that is what is shipped with the kits. These have been used for sometime in the LC53A kits and are not proto's. The diodes must be installed the way the silk on the board shows. The DTO5 boards are still Rev B and no changes have been made.

None of the boards shown in the pics are proto's but the same production boards that are shipped with the kits.

I would try it with the switch PCB plugged into the main PCB but NOT assembled into the L-bracket. In the pics it appears that some of the bent R's on the switch PCB are high and may be shorting to the L-bracket.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on October 08, 2016, 10:20:55 AM
Well I've doubled through, cleaned up the boards a little bit, .....
Hello,


doesn't look cleaned,a lot of solder flux on at least the main board.Also several leads are not cut propperly.
Maybe just cosmetic,but who knows.....


I second Jeff's comment on the leads of the bent resistors,some of them look like they have a full contact to the metal.


Best regards,


Udo.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on October 08, 2016, 04:17:33 PM
If this is all good then could it be the hum is created by the wiring outside the box?
I mean is there a patchbay and other gear the signal runs through?
Do you have other modules working propperly in your lunchbox?
Any unbalanced gear or cables in between?

Can you explain your listening chain?


Best regards,


Udo.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Johnkenn on October 08, 2016, 04:28:48 PM
Evening, gents. So...finished the build on a LC25...passes audio but no EQ works. Someone mentioned the relays? I'm nubistic, so be gentle...that's the blue Panasonic thingy's right? Maybe I'l try and touch up solder...Could it be the bypass?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on October 08, 2016, 04:35:11 PM
Evening, gents. So...finished the build on a LC25...passes audio but no EQ works. Someone mentioned the relays? I'm nubistic, so be gentle...that's the blue Panasonic thingy's right? Maybe I'l try and touch up solder...Could it be the bypass?

Bummer John, looks like we're both having problems!!! Yes those are the relays,I initially suspected a shotty solder job on two particular relay contacts myself... touched em up but I'm still having issues, hopefully yours gets sorted out as well! I hate not being able to see the solder job from the top but so is life depending on the components haha. Why not upload some pics if that doesn't sort it out and we can compare!

Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Johnkenn on October 08, 2016, 04:36:46 PM
Thanks man...I knew what I was getting into...this math and all. But it's part of the experience. We shall overcome.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on October 09, 2016, 12:44:50 AM


@geardude,


this was to rule out wether the hum issue is coming from the outside or the module itself,the way you describe it it looks like a ground loop.
Or is it the 60 Hz plus noise on top?
The signal chain looks good so far,although I don´t know your chinese box.In case all cables are balanced it should be o.k.
I have similar chains here (VP28s/Lovechild eqs/FF800),all good.
Listening to the vp28 without the eq added works correct,yes?(vp28 output directly patched to a ff802 line input).
You monitor directly the output of the ff802?
Does the box have grounding options like switches ,jumpers or solder pads?
Just questions to finally rule out things,but since you say the issue is there with the eq active and not in bypass then it looks like a module related thing.Best will be Jeff answers from now on because I don´t know these modules (yet).


Best,


Udo.

Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 09, 2016, 10:25:32 AM
I would confirm that all of the IC opamps are located/orientated properly especially the TL081 since its a single and the rest are duals. My next thing was to ask about the DT05.

I just yesterday got back my 2 built units from Paul Wolff that he had for AES. I am also in the midst of building a pair of LC25's for an engineer buddy who is tracking Joe Walsh tomorrow at House Of Blues here in Nashville. My back is a bit against the wall to get these done but can hopefully get the Test Points doc together to help pinpoint where things go south for you.

Is your bypass working properly?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: maq3396 on October 09, 2016, 10:51:21 AM
Hi Jeff,

Excuse the lack of knowledge here but I have not come across an explanation...

The frequencies of the two were obviously chosen for a reason.

What applications would you say each one is best suited for?

Thanks
Mac
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 09, 2016, 03:11:48 PM
Well, I just finished this pair of LC25's and they are working perfectly. I will collect some Test Point data to try and narrow down where your build goes south. It can be tricky trying to troubleshoot an odd problem that I have not encountered hands-on.

Something tells me its an opamp issue. If A6 and A7 are correct and A9 has been confirmed elsewhere, I would suspect A8 the DTO5. This can be confirmed by passing signal and measuring at the Test Points. Tips coming soon.

You can pass signal without the switch PCB inserted. This will put the relays into active mode and can remove possible issues on the switch PCB from the equation.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 09, 2016, 07:01:18 PM
Its not the official document but the results are the same.

I injected a 400Hz sine wave @ 0dBu with a HiZ load following the LC25.

TP1. -9.49dBu, 260mV AC
TP2. -9.5dBu, 259.7mV AC
TP3. -9.53dBu, 259mV AC
TP4. -9.53dBu, 259mV AC
Module's output, +0.03dBu

TP1 is after the DTO5 and before the 1st half of A6 (LME49720).
TP2 is between the two halves of A6 (LME49720)
TP3 is after A6 and before A9 (2520 style output amp)
TP4 is after A9 and before the 2503.

If you have the means, you can monitor or "listen" at any of the Test Points.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 09, 2016, 09:33:15 PM
I am not a DAW guy but know you can generate sine waves from the PC.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 10, 2016, 10:13:58 AM
The module needs to be powered up to run signal thru it.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 10, 2016, 02:50:31 PM
Alright sounds good thanks, I'll try my best and give it a go in the tight quarters. The module needs to be in active mode for this measurement I presume
Yes it does. Bypass is hard wire that simply connects the module's input directly to its output.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Johnkenn on October 10, 2016, 10:10:43 PM
So I had some of the diodes - first - in the wrong place. Got those switched to the right place. Still no luck. Found out I had the CR1 diode backwards. Got that fixed and the relays finally started working. But then started hearing crapping out which Jeff mentioned was probably a cold solder somewhere. So I touched up the entire switch pcb and boom - it's working. But - I do hear a drop in volume when it's in active mode. And it seems to change the tone a good bit even with EQ points zero'd out. Makes me wonder if I've futzed something else up.  I'm missing a small Allen tool (of course the one time I need it, it's the only one missing) so I haven't been able to really twist the knobs to see how it's effecting the sound...but painfully twisting the shafts seems to do what they're supposed to. I might try and touch up the main pcb tonight. Maybe that will cure my volume issue.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 11, 2016, 10:52:38 AM
By HiZ load, I mean the device following the LC EQ is not 600Ω but something much higher as in greater than 10kΩ. I would imagine most converters are 10kΩ or higher.

What level did you send out?

You may need to "listen" to the signal at those test points to find out where the buzzing is introduced.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 11, 2016, 04:52:14 PM
I sent out a 400hz sine at oDB where 0dbu=0dbfs
Again, I am no DAW guy but I know that 0dBfs will be more like +16dBu depending on how your rig is cal'ed. If you want to send a 0dBu tone your output level would be more like -16dBfs.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on October 11, 2016, 05:04:28 PM
thanks for clarifying, had a feeling that's what you meant when applied to the gainstaging.

Per the specs of my RME FF802 from the site/manual:

For my line out Output level at 0 dBFS @ +4 dBu: +13 dBu

I usually gun for around -18dbfs when recording so I'll repeat the test again and dial it in at the proper level which I guess according to the data above should be -13dbfs!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 11, 2016, 06:24:47 PM
You can easily measure it with your DMM. Touch your probes between the RME's output cable's XLR pin 2 and 3.

0dBu = 775mV AC

From what you posted my guess is -17dBfs will be 0dBu which is 775mV AC.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on October 14, 2016, 12:26:05 AM
Hi,


do you have a link to this snackbox?Built in psu or external?
The more I follow your posts the more I don't trust it.
You might also want to update your profile and add your location.
Maybe someone in your area has a "good" 500 or 51x rack to test them in?
This way you could at least get your rack out of the equation.


Just an idea,


Udo.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 14, 2016, 12:50:12 AM
I am with Udo at this point. I wonder about the rack. Unless oddly the exact same error was made maybe on the DTO5 board or something.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 18, 2016, 06:12:53 PM
Do you have a way to "listen" to the audio at the Test Points to see if the hum or buzz is present from the start? TP1 is right after the DTO5 amp.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 18, 2016, 09:47:18 PM
I think that will work. Just watch the volume so you don't blow a speaker.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 19, 2016, 02:35:33 PM
Alright so using the probe method described above and I do get the hum at Tp1 & throughout the rest of them
OK next try the same probe listening method at either end of RR2 which is 1k. Then try both ends of RR4 which is 160Ω.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on October 19, 2016, 03:03:32 PM
OK next try the same probe listening method at either end of RR2 which is 1k. Then try both ends of RR4 which is 160Ω.

RR2 and the hum is there, can't reach RR4 at the moment; trying to get creative with alligator clips but they bridge  to RR5 when connected...with the tiny space and the fact that it's hiding behind the 2622 its tricky to say the least ;) Let me fiddle around and see if I can pull it off
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on October 19, 2016, 03:53:39 PM
Ok so I added on some whisker's to both sides of RR4 and probing I'm getting the noise as well.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 19, 2016, 05:09:20 PM
OK. RR2 is between the 2622 and the DTO5 so problems here tell me its likely not the DTO5.

RR4 is before the 2622 and basically right at the card's input so problems here tell me it is not even on the EQ card.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 19, 2016, 06:59:07 PM
Thanks Jeff for the long winding troubleshooting! The box was indeed a suspicion. I'll be upgrading my box and testing this out in the meantime to fully confirm this as well!
Well, the LC25-LC40 cards are 100% fully VPR compatible. I will be interested to see what you find. It should be not much different than passing line signal thru a VP28 though.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on October 19, 2016, 07:02:48 PM
Thanks Jeff for the long winding troubleshooting! The box was indeed a suspicion. I'll be upgrading my box and testing this out in the meantime to fully confirm this as well!
Now I'm really curious how this works out.....
What do you mean by "upgrading my box"?
I still recommend to test the eq in a "trustworthy" rack,preferably from a well-known brand or the ones around here.Have never had any problems like this over all the years,I run eight racks with around 50 modules here.
Still looks to me like the problem is outside of your eq.


Best,


Udo.


Addendum:I tried to open the link on a mac running safari,did not work.Then on my ipad,worked but I can't seem to zoom in deep enough.
At least a "psu" is visible,looks like it is ac!
I wouldn't trust it,,maybe there's a supercheap smps board inside the rack.
The mains plug doesn't seem to have a safety gnd,right?
Also seems to have various link switches and insert points on (unbalanced?) jacks.
From this point on I seriously doubt the complete grounding scheme of your snackbox.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: 3nity on October 21, 2016, 12:55:02 PM
Just about to start my LC eq...really looking forward to!
By the way Jeff...what an awesome job you doing|! everything is topnotch!

By the way im using a Collective case 1U rack 3 space module...hope it meets all the requirements!
Thanks.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 21, 2016, 01:27:07 PM
Just about to start my LC eq...really looking forward to!
By the way Jeff...what an awesome job you doing|! everything is topnotch!

By the way im using a Collective case 1U rack 3 space module...hope it meets all the requirements!
Thanks.
Thanks 3nity  ;)  Dan's rack will work perfectly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on November 01, 2016, 03:57:42 PM
Now I'm really curious how this works out.....
What do you mean by "upgrading my box"?
I still recommend to test the eq in a "trustworthy" rack,preferably from a well-known brand or the ones around here.Have never had any problems like this over all the years,I run eight racks with around 50 modules here.
Still looks to me like the problem is outside of your eq.


Best,


Udo.

Well, the LC25-LC40 cards are 100% fully VPR compatible. I will be interested to see what you find. It should be not much different than passing line signal thru a VP28 though.
Addendum:I tried to open the link on a mac running safari,did not work.Then on my ipad,worked but I can't seem to zoom in deep enough.
At least a "psu" is visible,looks like it is ac!
I wouldn't trust it,,maybe there's a supercheap smps board inside the rack.
The mains plug doesn't seem to have a safety gnd,right?
Also seems to have various link switches and insert points on (unbalanced?) jacks.
From this point on I seriously doubt the complete grounding scheme of your snackbox.

Well it the problem was indeed the 3 slot "NoS snackbox" . Hooked both units into an API HC 6 slot and no problems. Talk about chasing your tail in circles when you got it right :o >:(

Thanks for the patience and help! I'm going to delete some of my posts as to not clog up this help forum. But lesson learned, don't skimp out on a cheap lunchbox alternative. 
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: kante1603 on November 01, 2016, 04:10:45 PM
Hi,


glad it's solved now.....and I can still trust my stomach,hahaha!


Now have fun (and get yourself a good rack.....or build one,it's easy!).


Cheers,


Udo.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: geardude on November 01, 2016, 04:19:15 PM
Hi,


glad it's solved now.....and I can still trust my stomach,hahaha!


Now have fun (and get yourself a good rack.....or build one,it's easy!).
Thanks brother, Indeed I shall. I scooped up this high current 6 rack used but down the line plan to build out a CAPI PSU & Rack. Till then this will do!  8)
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 02, 2016, 01:10:54 PM
Well it the problem was indeed the 3 slot "NoS snackbox" . Hooked both units into an API HC 6 slot and no problems. Talk about chasing your tail in circles when you got it right :o >:(
Excellent news! Glad you got it sorted. Congrats on nailing the builds out of the gate after all  ;)
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Wiz on November 08, 2016, 04:31:51 PM
I have a LC25 that I finished.... I could have sworn I checked everything was working by running sweeps.... but maybe I missed one.

My 12.8Khz band doesn't boost or cut.

Everything else works...

I have been over the board.. I am pretty sure everything is where it should be.

Any thoughts... 

cheers

Wiz
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 10, 2016, 10:24:51 AM
Hey Wiz, if all other bands are working fine then it must be the wiper/gyrator of the 12.8k switch.

So, on the switch PCB, it starts at the wiper of SW11 and goes to the pin JP2-5.

From there onto the Main PCB entering JP2-5.

Thru the series resistor GR30. The rest is the gyrator which is pins 1-3 of A5 as well as GR27 & 28 and caps GC19 & 20.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: 3nity on November 10, 2016, 05:56:08 PM
SO i just had a chance to pass some audio yesterday on my LC25 and im very proud to say that i works like a charm.
Is there no calibration needed i assume?

Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 10, 2016, 06:14:13 PM
SO i just had a chance to pass some audio yesterday on my LC25 and im very proud to say that i works like a charm.
Is there no calibration needed i assume?
No sir, no cal needed for these  ;D

Congrats! Humans win!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Fachjeremy on November 12, 2016, 06:42:20 PM
Hello guys, i've just finished my new lc40, but when i put it in the lunchbox,  the resistor PR2 has burn... Someone have an idea? I can send pictures...

Best regards

Jeremy
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 12, 2016, 10:26:31 PM
All eight "PR's" are damping R's on the power rails. If one or more smoke look for issues below.

PR1 = +V for IC's A1-5 and then onto SW PCB so look for a short near R1 or D3.
PR2 = -V for IC's A1-5
PR3 = +V for DTO5
PR4 = -V for DTO5
PR5 = +V for A9
PR6 = -V for A9
PR7 = +V for A6-7
PR8 = -V for A6-7
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Fachjeremy on November 13, 2016, 02:34:29 AM
All eight "PR's" are damping R's on the power rails. If one or more smoke look for issues below.

PR1 = +V for IC's A1-5 and then onto SW PCB so look for a short near R1 or D3.
PR2 = -V for IC's A1-5
PR3 = +V for DTO5
PR4 = -V for DTO5
PR5 = +V for A9
PR6 = -V for A9
PR7 = +V for A6-7
PR8 = -V for A6-7




For now, i've just PR2 who has smoke.  Have you an idea? I have placed the opamps on pcb socket, it is ok?
Have you some value  who can i Check? Can i put in the lunchbox for test, less PR2?

Sorry but i don't really understand your answer above.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 13, 2016, 09:41:09 AM
If PR2 smoked you have a short or problem on the -V rail that supplies the IC opamps A1 thru A5. Or maybe one of them is installed backwards? Or you have shorted the pins for C2. If not that you have a solder bridge that touches one of the #4 pins on one of the A1 thru A5 opamps.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Fachjeremy on November 13, 2016, 11:29:25 AM
If PR2 smoked you have a short or problem on the -V rail that supplies the IC opamps A1 thru A5. Or maybe one of them is installed backwards? Or you have shorted the pins for C2. If not that you have a solder bridge that touches one of the #4 pins on one of the A1 thru A5 opamps.

Ok, thanks you, i will check all of this. I will keep you informed.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Fachjeremy on November 13, 2016, 12:24:12 PM
Just one thing again. The Jumper JP3-3 is in the good way?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 13, 2016, 02:37:33 PM
JP3 is the DC link. It will connect other LC25 or LC40's Bypass controls. If you have 2 units side by side and the rack supports DC linking on pin #6, set both jumpers to "Y" for Yes. With both units in Active mode, flipping either one to Bypass with make both (or more) units also Bypass. This can be done with a rack full of 11 units if so desired.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Wiz on November 14, 2016, 03:52:33 PM
I have a LC25 that I finished.... I could have sworn I checked everything was working by running sweeps.... but maybe I missed one.

My 12.8Khz band doesn't boost or cut.

Everything else works...

I have been over the board.. I am pretty sure everything is where it should be.

Any thoughts... 

cheers

Wiz

Thanks Jeff...

turns out poor solder joint on the Gyrator.

all good now...

thanks again

Cheers

Wiz
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Fachjeremy on November 17, 2016, 03:32:33 AM
Sound Great!!! Thanks a lot Jeff, now it's time to built a second... For stereo configuration.
https://www.youtube.com/watch?v=nTKqTsQJJgA
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on November 17, 2016, 10:27:08 AM
Sound Great!!! Thanks a lot Jeff, now it's time to built a second... For stereo configuration.
https://www.youtube.com/watch?v=nTKqTsQJJgA
Awesome Jeremy! Thanks for sharing!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: deadpoet on December 02, 2016, 05:41:21 AM
Just a quick thumbs up for all things CAPI.

My first endeavor was a pair of VP28's, a pair of LC40's and 10x 2520 kit (with a pair of BT50's in the mail).

Building and testing went very well although the DOA's (just under 30minutes each) and 10 greyhills on the LC40 (about 4 hours in total for a single LC40) aren't *that* much fun to build  ;D


Good to know that you can install a DTO5 upside down and apply power for about 2 minutes (while wondering why it passes no audio  ::) ) WITHOUT it burning up or getting harmed in any way.


Thanks!
Herwig
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on December 02, 2016, 10:17:42 AM
Good to know that you can install a DTO5 upside down and apply power for about 2 minutes (while wondering why it passes no audio  ::) ) WITHOUT it burning up or getting harmed in any way.
Yikes! Glad no harm was done.  :o
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: muffy1975 on February 20, 2017, 06:08:57 PM
Hi guys,

if anyone can be bothered,

can someone post a picture of the underside of their LC eq pcbs? Just want to connect the dots wit the mxr 108 eq which looks identical?

Michael
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: mysticmerlin on April 11, 2017, 02:45:02 PM

Hi, just built 2 LC25's. One is working fine but the second one is like 10db down and none of the left hand switches work, the right hand column switches seem to work fine. Any ideas welcome. Thanks
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on April 11, 2017, 06:11:49 PM
Hi, just built 2 LC25's. One is working fine but the second one is like 10db down and none of the left hand switches work, the right hand column switches seem to work fine. Any ideas welcome. Thanks
Possibly a bad solder joint on the headers or could be on one or more of the vertical R's on the switch PCB.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: mysticmerlin on April 12, 2017, 04:30:36 AM
Thanks Jeff, I'll check that and get back.
Great gear by the way. The lc25 is just the ticket for shaping drums.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: mysticmerlin on May 08, 2017, 06:57:17 AM
As usual you were right. I had a header that had a bad connection.  Working fine now. Sounds great.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on May 08, 2017, 09:34:05 AM
As usual you were right. I had a header that had a bad connection.  Working fine now. Sounds great.
Excellent!!  :)
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jchudyk on June 10, 2017, 11:19:15 AM
Hey Jeff!

Any known issue of compatibility with older API consoles of lunchboxes?

My LC25 works great in newer API boxes but in some older boxes, like the custom API console I have (the one I sent you a picture of) the LC25 does not pass audio when active. It bypasses audio just fine.

Any thoughts? Might have to do with the relay?

The build is done as it should be, just wondering if there is something I can do to have it work in that console. Bypass the bypass?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on June 10, 2017, 11:45:13 AM
Hey Jeff!

Any known issue of compatibility with older API consoles of lunchboxes?

My LC25 works great in newer API boxes but in some older boxes, like the custom API console I have (the one I sent you a picture of) the LC25 does not pass audio when active. It bypasses audio just fine.

Any thoughts? Might have to do with the relay?

The build is done as it should be, just wondering if there is something I can do to have it work in that console. Bypass the bypass?
Hey Joe, sounds to me like that console is not 500 series compatible. All of my VPR style modules will work properly in any true VPR style rack. I would further investigate the pinouts on that thing.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jchudyk on June 10, 2017, 12:07:10 PM
Thanks Jeff,

All my other modules work great in it, including the BT50s and FC526s. The LC25 also seems to have an issue in the old 10 slot API rack, the one with the optional 48v.

Audio comes in to the edge connector on pins 8+10 then pins 2+4 go to the API fader and those return to the bus cards.

Pins 12,13 ,14 get power correctly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on June 10, 2017, 12:47:58 PM
Thanks Jeff,

All my other modules work great in it, including the BT50s and FC526s. The LC25 also seems to have an issue in the old 10 slot API rack, the one with the optional 48v.

Audio comes in to the edge connector on pins 8+10 then pins 2+4 go to the API fader and those return to the bus cards.

Pins 12,13 ,14 get power correctly.
Make sure the DC-link shunt jumper is set to "N". There is no gold finger for the 48V pin on the card edge. There is really nothing different about this card compared to the others you have.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: mdmitch2 on June 10, 2017, 01:18:00 PM
I built one of the LC25s and  tried it on a horribly recorded kick, which I had previously sample replaced. Within 20 seconds, I had a great sounding track... pretty unbelievable.

Also I thought the 25hz band might only be useful for cutting, but was surprised to find that it's  very useful for boosting, and adding some major heft.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Potato Cakes on June 21, 2017, 03:26:48 AM
Does anyone know what the signal level is needed to activate the peak light? I tried pounding it with signal till my converters clipped and it still doesn't light up. I jumped the - side of the LED to ground and it lights up, so I know it's working. I know it probably has more headroom than my converters, I was just trying to find a way to check to see if it was working properly.

Everything else works properly right out of the gate.


Thanks!

Paul
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on June 21, 2017, 09:46:12 AM
Does anyone know what the signal level is needed to activate the peak light? I tried pounding it with signal till my converters clipped and it still doesn't light up. I jumped the - side of the LED to ground and it lights up, so I know it's working. I know it probably has more headroom than my converters, I was just trying to find a way to check to see if it was working properly.

Everything else works properly right out of the gate.


Thanks!

Paul
It should fire off at around +28dBu. Try sending it a high level and cranking a few EQ bands.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Potato Cakes on June 21, 2017, 11:09:00 AM
I did try cranking some of the bands. I think +28 is quite a bit more than what I can output. I'm not going to worry about it. If I ever need it that hot I'm doing something wrong.

As always,  excellent work!

Thanks!


Paul
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: AndyKolp on October 01, 2017, 04:27:28 PM
First time poster, 3rd piece of CAPI gear (2-vVP28's - awesome) I just finished my first LC40 EQ. As far as the Grayhill switches go, if I happen to install 5 of them backwards (which I did) such that the stop pin is at the 6 o'clock position, would that cause the eq not to function properly?  When I turn switch from bypass to on, and all rotary switches at 0 position, the db level drops slightly and bottom 4 knobs only change the sound when turned one click counter-clockwise. The 11 o'clock position causes an INCREASE in db for those bands. I think I really hosed this up. My plan is to use the desoldering vacuum at work and try to salvage the switches so I can install them correctly.  I was just wondering if the lack of function is due to incorrect installation of the rotary switches, or if I need to look at other things as well.

Also, I may have exposed Q3 and Q5 on the DTO5 to too much heat as I swapped them accidentally and needed to solder wick them out. Not sure if this could also be the problem. Good times..

Thanks for any help
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 01, 2017, 05:01:57 PM
Yeah those switches need to be seated correctly or their 0 position will be somewhere other than 0 on the panel. If you have the knob pointing to 0 then you will have some boost or cut happening at those positions.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: duantro on October 24, 2017, 06:35:32 PM
Finished an lc25 and it sounds great. The switches don’t turn smoothly though. I used a spacer to get the knobs off of the nuts, but some positions don’t have a clean “click” feel. Almost feels like the knob is spinning, but it’s not. Any thoughts?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 25, 2017, 12:04:06 PM
Finished an lc25 and it sounds great. The switches don’t turn smoothly though. I used a spacer to get the knobs off of the nuts, but some positions don’t have a clean “click” feel. Almost feels like the knob is spinning, but it’s not. Any thoughts?
Hmm, not sure I am familiar with this although I do recall someone early on who didn't have the switches properly seated when soldering. Once he tightened them down thru the bracket and faceplate it must have but a strain on the innards and some did not turn smooth. Not sure what else it could be.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Studio Mollan on August 20, 2018, 06:53:28 PM
Hi,
I've kust built a pair of LC25s and im having trouble with one of them. When engaged with all switches in "0" position im getting about 6db level boost.  Its flat, a +6db copy of the bypass signal. the bands work as they should however the 100Hz band is acting as a HI pass from -6 to -15 and something similar in the 6200hz band.
Ive tested different DOAs, all confirmed working in other gear. Ive confirmed that the slot in my 500 rack is wired, and working, properly. Ive reheated all solder joints on the entire pcb, including the Switch PCB. Cant find anything wrong by looking at the pcb. All components are seated and they match the working unit.
could it be a bad rotary switch?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on August 20, 2018, 09:30:05 PM
Hi,
I've kust built a pair of LC25s and im having trouble with one of them. When engaged with all switches in "0" position im getting about 6db level boost.  Its flat, a +6db copy of the bypass signal. the bands work as they should however the 100Hz band is acting as a HI pass from -6 to -15 and something similar in the 6200hz band.
Ive tested different DOAs, all confirmed working in other gear. Ive confirmed that the slot in my 500 rack is wired, and working, properly. Ive reheated all solder joints on the entire pcb, including the Switch PCB. Cant find anything wrong by looking at the pcb. All components are seated and they match the working unit.
could it be a bad rotary switch?
I doubt its a bad switch. My guess is an error in the vertical resistor placement on the switch PCB. It would be a pain to test with all of the knobs but you could swap the switch PCB assembly between the units and see if the problem follows or stays. That will help narrow things down. Also, make 100% sure that no R's are too tall and making contact with the back of the L-bracket.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Studio Mollan on August 21, 2018, 02:58:02 PM
I doubt its a bad switch. My guess is an error in the vertical resistor placement on the switch PCB. It would be a pain to test with all of the knobs but you could swap the switch PCB assembly between the units and see if the problem follows or stays. That will help narrow things down. Also, make 100% sure that no R's are too tall and making contact with the back of the L-bracket.
Found the problem. A broken trace between R15-R16. Worksfine now. Thanks!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: myers1st on September 10, 2018, 04:20:57 PM
Hi all-

I've just finished an LC25 and have the 'pass audio but no EQ' problem.  I do tidy builds and all solder joints are double-checked and  good.  I've also checked:

- 1731 op amp is good, works fine in my VP28.
- Transformers are good
- Chip placement and orientation is correct (I socketed them).
- Diode polarity is correct
- 90 degree pin headers and sockets to the switch PCB have clean joints and are seated well
- DC link shunt is in place "N"

Seems like it could be a relay?  I retouched all the pins to be safe but still nothing.  Ideas of where to look?

Thanks.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on September 13, 2018, 12:08:21 PM
Hi all-

I've just finished an LC25 and have the 'pass audio but no EQ' problem.  I do tidy builds and all solder joints are double-checked and  good.  I've also checked:

- 1731 op amp is good, works fine in my VP28.
- Transformers are good
- Chip placement and orientation is correct (I socketed them).
- Diode polarity is correct
- 90 degree pin headers and sockets to the switch PCB have clean joints and are seated well
- DC link shunt is in place "N"

Seems like it could be a relay?  I retouched all the pins to be safe but still nothing.  Ideas of where to look?

Thanks.
You can check continuity between the rack's input and output XLRs. There should be basically a direct connection via the relays when the unit is bypassed and no DCR continuity when active. Check both pins 2 to 2 and 3 to 3. That should give an indication if the relay bypass is working properly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: myers1st on September 13, 2018, 01:59:48 PM
Indeed there is direct connectivity on pins 2 and 3, when bypass switch is in either position.  The green/red LEDs work by the way.  I tested the switch and it is working like it should.  Does this confirm that the problem is the relays?

Thanks Jeff!

You can check continuity between the rack's input and output XLRs. There should be basically a direct connection via the relays when the unit is bypassed and no DCR continuity when active. Check both pins 2 to 2 and 3 to 3. That should give an indication if the relay bypass is working properly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on September 13, 2018, 02:33:55 PM
Indeed there is direct connectivity on pins 2 and 3, when bypass switch is in either position.  The green/red LEDs work by the way.  I tested the switch and it is working like it should.  Does this confirm that the problem is the relays?

Thanks Jeff!
It confirms a problem with the relay circuit. Likely not the relays themselves. The LEDs are part of the control circuit but not exactly telling you if the relays have flipped their state or not.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: myers1st on September 13, 2018, 02:36:37 PM
Ok, will try to trace through the relay circuit and see if I can find anything, thanks.

It confirms a problem with the relay circuit. Likely not the relays themselves. The LEDs are part of the control circuit but not exactly telling you if the relays have flipped their state or not.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on September 13, 2018, 07:07:23 PM
Ok, will try to trace through the relay circuit and see if I can find anything, thanks.
Are you 100% sure the zeners and 914s were not mixed up?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: myers1st on September 13, 2018, 11:38:49 PM
110% sure!  I always double and triple check every component before I... er... hang on a minute... man these are hard to read... okay maaaaaybe CR1 and CR2 were swapped.  Wow, this sounds a lot better when it's not bypassed!

Thanks Jeff!  Amazing stuff as always.

Are you 100% sure the zeners and 914s were not mixed up?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on December 10, 2018, 06:28:08 AM
Hi all,
I just finished my first of 2 LC25 yesterday but when i put in a DOA (Prebuilt JE-990 by Haibrall) PR5 and PR6 went up in smoke.
PR5&6 connect to the supply voltages of the DOA (+15, -15V) which I measured before. The DOA worked well in a Haibrall Lola and a CAPI VP28 before. Additionally to the burnt resistors the  the Output transistors of the DOA got really hot. I also measured that TP4 connects to ground, is that ok (via 2503?)?
I also checked the DOA on it's own ie connected it to a supply where each (+ and -) consumed about 2mAmps. I don't know where to look.

Greetings from Graz
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on December 10, 2018, 10:03:44 AM
Hi all,
I just finished my first of 2 LC25 yesterday but when i put in a DOA (Prebuilt JE-990 by Haibrall) PR5 and PR6 went up in smoke.
PR5&6 connect to the supply voltages of the DOA (+15, -15V) which I measured before. The DOA worked well in a Haibrall Lola and a CAPI VP28 before. Additionally to the burnt resistors the  the Output transistors of the DOA got really hot. I also measured that TP4 connects to ground, is that ok (via 2503?)?
I also checked the DOA on it's own ie connected it to a supply where each (+ and -) consumed about 2mAmps. I don't know where to look.

Greetings from Graz
Can you check again the resistance from the DOA output pin to ground? This should be a very low resistance so set your DMM accordingly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on December 10, 2018, 04:22:07 PM
I fixed it. Your first instinct was right. One of the 99ers has gone bad.  The other one  of the pair i got works (for now, for a 99er).  Now I gotta find a cold solder somewhere in the relais-switching path. Those get triggered by the slightest vibrations. The gyrator switches seem fine but i suspect there will be another cold spot or two. Any idea how to spot them correctly?

The output pin resistance to ground was something like 10 to 50 Ohms if I remember correctly.

Thank you
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on December 12, 2018, 07:21:59 PM
So I checked all the solder joints on the switches and relais circuit. AFAICT The Unstable relais switch was caused by a cold solder joint at Q1. All the bands are working fine. My Problem now is that the unit emits a high-pitched hum. The hum is gone when I turn down the 1.6kHz band 4 dB. Jeffrey do you have any clue for me how to fix this? Also the unit seems a little bit noisy (even  with no source connected).

Best regards and Thank You for your help
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on December 12, 2018, 08:41:06 PM
Sorry Jeff, I got that too. Turns out testing a unit alone in the middle of a 6 slot rack can lead to weird radio interferences. That included the ringing noise and low humming every time my hand entered the inside of the rack.

I love the LC25 by the way. Such a powerful shaping tool. I had a lot of fun testing it out with my electric guitar. Can't wait to tweak some drums. Great job and a great kit. Cheers and good night.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on December 12, 2018, 09:13:01 PM
Sorry Jeff, I got that too. Turns out testing a unit alone in the middle of a 6 slot rack can lead to weird radio interferences. That included the ringing noise and low humming every time my hand entered the inside of the rack.
What rack are you using? When we build them and test, they are wide open laying on a bench with a test jig. No enclosure. No noise or hum at all. That is why I am questioning the rack you are using.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on December 14, 2018, 10:40:37 AM
What rack are you using? When we build them and test, they are wide open laying on a bench with a test jig. No enclosure. No noise or hum at all. That is why I am questioning the rack you are using.

I have 2 racks by Rupert Neve Designs. I used a empty rnd r6 where i had the issues, Then i put it in a almost full rnd R10. I like them but they have no linear power supply afaik.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Blackdawg on January 31, 2019, 01:33:30 AM
Hey Jeff,

I am eyeing a pair of LC25 and LC40 and am curious about a modification.

Which resistors effect the gain of the grayhills? Would it be possible to modify them for smaller steps?

As in possibly these gain steps:

-9
-6
-3
-2
-1
-0.5
0
+0.5
+1
+2
+3
+6
+9

Could make for a cool mastering eq I think.

Normally this would be simple but looking at how you have the switches on the PCB it looks like they are actually sharing resistors? Is that true?

And if this is possible....can some custom faceplates be ordered? :)

Thanks Jeff!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on January 31, 2019, 10:18:26 AM
Yes that's possible but not sure its something I would have the time for. There are 2 resistor ladders for cut/boost. Each has 5 switches. You would need to rework those R's All on the switch PCB that the Grayhill's mount to. My screen shop is not really conducive to small runs or custom orders. They do fabulous work but it would cost $380 for new films and then a minimum dollar amount per run. They only make sense for large runs.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Blackdawg on January 31, 2019, 11:28:35 AM
Yes that's possible but not sure its something I would have the time for. There are 2 resistor ladders for cut/boost. Each has 5 switches. You would need to rework those R's All on the switch PCB that the Grayhill's mount to. My screen shop is not really conducive to small runs or custom orders. They do fabulous work but it would cost $380 for new films and then a minimum dollar amount per run. They only make sense for large runs.

Gotcha.

Well I could always attempt my own panel which sounds like a terrible idea..haha

Is it possible to get the schematic of the ladder at least to wrap my head around it to help figure out what I'd need to make that happen? I can of course shoot you an email about this if that would be better.

Thanks Jeff!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on January 31, 2019, 01:38:28 PM
Gotcha.

Well I could always attempt my own panel which sounds like a terrible idea..haha

Is it possible to get the schematic of the ladder at least to wrap my head around it to help figure out what I'd need to make that happen? I can of course shoot you an email about this if that would be better.

Thanks Jeff!
Yes send me an email. I prepared this info for a guy before but once he realized what was actually involved he never followed thru with the build.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Blackdawg on January 31, 2019, 05:19:13 PM
Yes send me an email. I prepared this info for a guy before but once he realized what was actually involved he never followed thru with the build.

Pff. Lame.

I am motivated  8)

Email sent!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on February 01, 2019, 04:38:36 PM
Hey Jeff,

I finally got around building my second one. It sounds and works really great with one caveat: The status LEDs don't work/ Do you have any ideas what to check (beside Diode direction)?

Have a nice weekend
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on February 01, 2019, 09:02:06 PM
Hey Jeff,

I finally got around building my second one. It sounds and works really great with one caveat: The status LEDs don't work/ Do you have any ideas what to check (beside Diode direction)?

Have a nice weekend
LED direction as well as the 1N914s on the switch PCB.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Thekahn on February 24, 2019, 10:16:21 PM
Hi Jeff,
Thought everything was good on my LC40 build, but upon closer examination, the 5khz knob only moves in maybe .5 dB increments.  I checked using a plugin called “plugin doctor” to check the curves of everything. Any areas specifically I should check for cold solder joints etc?  Thanks in advance,
Chris
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: saturnjayzero on February 25, 2019, 04:10:32 PM
LED direction as well as the 1N914s on the switch PCB.

I found the error.  A small chip/tear of the pcp on the bottom edge has stopped the voltage from reaching R1. It's the lane layouted along the outmost edge of the pcb. Any suggestions from where to start a wire bridge?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on March 09, 2019, 04:49:00 PM
Hi Jeff,
Thought everything was good on my LC40 build, but upon closer examination, the 5khz knob only moves in maybe .5 dB increments.  I checked using a plugin called “plugin doctor” to check the curves of everything. Any areas specifically I should check for cold solder joints etc?  Thanks in advance,
Chris
The 5kHz gyrator is comprised of GR21, GR22, GR24, GC15 and GC16. Also half of A4 which is shared with 2.5kHz. If that is fine I would ASSume the chip is fine.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: adam.schw on March 16, 2019, 05:22:51 PM
Hello,

I built my LC25 a month back or so. Haven't turned it on in a little while because i've been busy with vacation and life.  It was working totally normal last time I used it, but for some reason the unit is not passing any audio anymore. When I bypass the unit, audio goes through, but once I switch it to active, nothing. I've tried different slots in my box to no avail. I do not have a spare DOA sitting around, should building another DOA and tossing it in be the first step?

Thanks,
Adam
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on March 16, 2019, 05:54:02 PM
Hello,

I built my LC25 a month back or so. Haven't turned it on in a little while because i've been busy with vacation and life.  It was working totally normal last time I used it, but for some reason the unit is not passing any audio anymore. When I bypass the unit, audio goes through, but once I switch it to active, nothing. I've tried different slots in my box to no avail. I do not have a spare DOA sitting around, should building another DOA and tossing it in be the first step?

Thanks,
Adam
Is your opamp fully seated?
http://capi-gear.com/catalog/DOA_Install.php
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: adam.schw on March 17, 2019, 07:13:18 PM
Is your opamp fully seated?
http://capi-gear.com/catalog/DOA_Install.php

Yeah, she's snapped into place.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on March 17, 2019, 07:52:39 PM
Well, if its not the opamp it could be a bad/cold solder joint somewhere. If things were working fine and then stopped, that's usually the case.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: adam.schw on March 19, 2019, 10:59:41 AM
Well, if its not the opamp it could be a bad/cold solder joint somewhere. If things were working fine and then stopped, that's usually the case.

 I mean I had it on and working for probably 20 or so hours  so it wasn’t just a brief thing.  I’ll order up an op amp today and see if that doesn’t sort it out if not I guess I’ll have to start searching the board for other issues 😐
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: adam.schw on March 30, 2019, 06:23:17 PM
Hey Jeff,

Ordered a new 2520 and 1731 to see if the op amp helped. My unit is now working, but the 1731 has a very considerable amount less of headroom (something like 8db) before noticeable saturation. Is the normal or do you think I botched something on the 1731? Either way, I'm happy that the unit is working again!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on March 31, 2019, 01:40:37 AM
Hey Jeff,

Ordered a new 2520 and 1731 to see if the op amp helped. My unit is now working, but the 1731 has a very considerable amount less of headroom (something like 8db) before noticeable saturation. Is the normal or do you think I botched something on the 1731? Either way, I'm happy that the unit is working again!
This is way not normal. There should be zero difference in headroom between properly built discrete opamps.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: adam.schw on March 31, 2019, 01:39:21 PM
This is way not normal. There should be zero difference in headroom between properly built discrete opamps.

Oops! Reversed the Q7 and Q8. Thanks Jeff!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Thekahn on April 08, 2019, 09:40:30 AM
The 5kHz gyrator is comprised of GR21, GR22, GR24, GC15 and GC16. Also half of A4 which is shared with 2.5kHz. If that is fine I would ASSume the chip is fine.

Hi Jeff,
I resoldered all of the resistors and caps listed above, as well as each point on the 5k knob, and the problem still exists... i might get a dB or two boost or cut at 5k with the knob FULLY cranked. I’m wondering if I should replace the two caps GC15 and GC16? Thoughts?
Thanks again for your time!
Chris
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on April 08, 2019, 09:56:42 AM
Hi Jeff,
I resoldered all of the resistors and caps listed above, as well as each point on the 5k knob, and the problem still exists... i might get a dB or two boost or cut at 5k with the knob FULLY cranked. I’m wondering if I should replace the two caps GC15 and GC16? Thoughts?
Thanks again for your time!
Chris
Post a pic of that section of the PCB. I wanna check and see that the R's are placed correctly.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Thekahn on April 14, 2019, 04:54:44 PM
Post a pic of that section of the PCB. I wanna check and see that the R's are placed correctly.

see the photo below.
Thanks Jeff.
- Chris
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on April 15, 2019, 09:46:09 AM
see the photo below.
Thanks Jeff.
- Chris
Looks like you have GR14 and GR22 mixed up.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Thekahn on April 18, 2019, 11:50:52 PM
Looks like you have GR14 and GR22 mixed up.
That did the trick! Thanks so much Jeff, I’ve said it many times... but you are “the man”! Cheers,
Chris
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: staylor200 on May 01, 2019, 02:06:39 PM
Hi. Just completed an LC25. At first power up, PR6 started to smoke, then the green active LED stopped working. Thanks in advance for any help!

Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Potato Cakes on May 01, 2019, 02:14:58 PM
Hi. Just completed an LC25. At first power up, PR6 started to smoke, then the green active LED stopped working. Thanks in advance for any help!

Read through this thread. You'll find things to check like op amp, solder joints, etc. Did you build the op amp? Did you power it up with no op amps installed? Are all of the ICs oriented correctly? Do you have an extension jig to test voltages?

Thanks!

Paul
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: duantro on May 10, 2019, 08:00:12 PM
I've built a LC25 and it works, but is distorted and the peak light is on. I'll check for bridges and placement of parts.

edit: I pulled 2520 out and powered up, to see if it was maybe an opamp issue. no clip light, but r17/ 10r  went up in flames!
I inspected gar 2520 and it looks like I misread the "do not bridge/ bridge these pins for support" I must be going colorblind. maybe these circles should be yellow and red, instead of maroon and red! I had bridged the input + pin to c1 on the 2520. I've removed the bridge and will look for another 10r resistor and try it again tomorrow.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: Leon on June 20, 2019, 03:13:36 PM
Hey Jeff,

I am eyeing a pair of LC25 and LC40 and am curious about a modification.

Which resistors effect the gain of the grayhills? Would it be possible to modify them for smaller steps?

As in possibly these gain steps:

-9
-6
-3
-2
-1
-0.5
0
+0.5
+1
+2
+3
+6
+9

Could make for a cool mastering eq I think.

Normally this would be simple but looking at how you have the switches on the PCB it looks like they are actually sharing resistors? Is that true?

And if this is possible....can some custom faceplates be ordered? :)

Thanks Jeff!

Hello there. How is the mod going?

I would be interested in the mod also. The large gain step is the only thing that prevents me from ordering a pair of LC25. 

Thanks,
Leon
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: IanB on October 29, 2019, 07:12:03 PM
Just finished an LC 40 & a 25.
25 = perfect.
40: 40hz & 2.5k are inactive. I re-flowed those parts of the pot board and main pcb  today & just retested; still no dice.
I’m assuming the chips are fine as 80 & 5 work fine.
I’ll swap the pot board with the LC25 tomorrow and see if that works (my a keys are at work! Numpty!).
It also looks (in Q Clone) that 5, 10 & 20 are shelving, not bell curving which is weird, right?
Ian
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 29, 2019, 10:06:40 PM
Just finished an LC 40 & a 25.
25 = perfect.
40: 40hz & 2.5k are inactive. I re-flowed those parts of the pot board and main pcb  today & just retested; still no dice.
I’m assuming the chips are fine as 80 & 5 work fine.
I’ll swap the pot board with the LC25 tomorrow and see if that works (my a keys are at work! Numpty!).
It also looks (in Q Clone) that 5, 10 & 20 are shelving, not bell curving which is weird, right?
Ian
One or 2 things at a time...first like you said swap the switch sub assembly and see about 40Hz and 2k5. If that doesn't do it, post a pica of the gyrator caps and R's for those sections. Its super easy to mix up some R's that are 10x different.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: IanB on October 30, 2019, 06:08:15 AM
A1 section
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: IanB on October 30, 2019, 06:08:54 AM
A4....
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: IanB on October 31, 2019, 11:25:28 AM
Right. Swapped over the pot PCB’s. It’s not that. Have I screwed up the gyro circuits x 2?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on October 31, 2019, 12:07:35 PM
Right. Swapped over the pot PCB’s. It’s not that. Have I screwed up the gyro circuits x 2?
I am thinking you have 4 gyrator sections messed up.

GR4 should be 1k87 and you have it 187k.

GR19 should be 2k05 and you have it 205k.

Find where you put the 1k87 and 2k05 and swap those parts and I'm betting your weird shelving action with the upper bands will be correct.
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: IanB on October 31, 2019, 08:19:45 PM
And of course you are right!!
Working on all freq’s!
Thank you so much for your time & help!
So stoked!
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: iamnotacowboy on August 27, 2020, 02:14:26 AM
I finished my pair of LC40s. Upon applying power, both units smoked. (I did test them one at a time) When I looked at the circuit, PR4 and PR5 are the items that look cooked on each unit. Did I follow the directions wrong in the exact spot on two different units a couple days apart?! I s’pose that’s possible. These are the 10 ohm power damping resistors. Any ideas?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: jsteiger on August 27, 2020, 10:45:03 AM
I finished my pair of LC40s. Upon applying power, both units smoked. (I did test them one at a time) When I looked at the circuit, PR4 and PR5 are the items that look cooked on each unit. Did I follow the directions wrong in the exact spot on two different units a couple days apart?! I s’pose that’s possible. These are the 10 ohm power damping resistors. Any ideas?
https://groupdiy.com/index.php?topic=63983.msg814157#msg814157
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: iamnotacowboy on September 06, 2020, 01:35:59 AM
So I did some inspecting, trying to figure out the issue. Replacing the resistors and using a different opamp got the eqs working perfectly and they sound great. So the issue seems to be with the opamps. I was able to visually inspect the solder joints, but that's about the limit of my knowledge. Any hint for my steps?
Title: Re: [Build] CAPI LC25-LC40, 500 Series Rotary Graphic EQ's, Official Support Thread
Post by: iamnotacowboy on September 09, 2020, 01:15:50 AM
Inspecting the board doesn’t show any funny solder connections. The two units failed in the exact same way, but I don’t know what to look for beyond solder issues. Anybody got a tip?