[BUILD] CAPI FC526~500 Series~FET Limiter Kit~Official Support Thread

[ChristianFrentzen]

Okay, another afternoon and some measurements later - they are finally matched. I made sure to check TP7 to see if my FET Bias DC Voltage was just like written on my PCB. So I re-calibrated both units. Now they are very very close and I like them so much. That compression is extremely versatile. Man, I'm really happy. Cheers everybody!

 

[rhythmbeard]

Hi all,
Is there a change in the new rev replacing CR3? or is it packed somewhere other than in the bags for the Main PCB?
I thought I was an idiot and had maybe lost the diode(I am an idiot, this is very possible) however, I ordered two compressor kits together and it appears they both came with the same number of diodes, with no CR3. Did I do something goofy??

 

[jsteiger]

Hi all,
Is there a change in the new rev replacing CR3? or is it packed somewhere other than in the bags for the Main PCB?
I thought I was an idiot and had maybe lost the diode(I am an idiot, this is very possible) however, I ordered two compressor kits together and it appears they both came with the same number of diodes, with no CR3. Did I do something goofy??

Send me an email thru the store with your order number. We missed the 4V3 zener in a handful of kits. I'll mail you one.

 

[Yannis]

Hello !
I take my chance 10 months after again
What can be the issue between TP3 and TP4 ?

 

[jsteiger]

Hello !
I take my chance 10 months after again
What can be the issue between TP3 and TP4 ?

TP3 and 4 are not exactly related to each other. TP3 is just before the final output transformer. TP4 is in the sidechain signal path.

 

[Yannis]

Thanks OK ! Actually the most of TP are OK except the Sidechain Audio Path is not feed properly.

Would you have advices, i never found the issue ?

 

[Toobme]

Ok, I posted this a few days ago, but some things are cleared up, and I wanted to pose a clearer question.
I'm getting -15.9v at TP9. If it's supposed to be -10v, can I proceed and make adjustment during calibration, or am I basically hooped?

Note that the unit functions as a compressor, LEDs work, gain reduction, etc. all working. Just not calibrated, due to the above question.
Does anyone have an idea as to that extra voltage?

Thanks very much for any suggestions!

 

[Toobme]

It turns out I need a better DMM!

I borrowed one and ran everything on the calibration sheet to the specified levels.
It's perfect!

My old meter was just way off and wasn't one that could be calibrated.
Any suggestions on a good one that does true RMS and VU under $300?
Or is that too low to get good enough resolution for these kinds of builds.

Thanks!

 

[achase4u]

Hey ladies and gents...

My wonderful FC526, has died. Ish.

Worked famously for a while, then when I went to use it tonight, things sounded thin. Traced it to just the FC526. Swapped op amps in case, no dice. Basically when in bypass, it passes fine(hard bypass) but nothing I do changes the sound in active mode. It's very thin and bright, like an EQ has been applied.

Any clue as to what this might be and where to start checking? Thanks...

 

[jsteiger]

Classic symptoms of bad solder joint(s).

 

[achase4u]

Classic symptoms of bad solder joint(s).

Ah ha, thank you. I will go on the hunt for them. Appreciate it!

 

[rhythmbeard]

Ooooooooo do I have a mystery for you Mr. Steiger!!
So I just finished calibrating my FC526 XFMR - and everything has been going great, got to the final stages of calibration and got TP10 right in the sweet spot! Everything is working great, sounding great. Play some keyboards through it, sounds amazing. Now, I've been doing all my testing, and thus far all my playing with the module inserted into my CAPI 11 space rack - I pulled the compressor out of the 11 space so I could install the rack else where, and pop the compressor into the last slot of my RND R6 500 rack. And now the compressor goes all "me want honeycomb" on me and starts acting completely nuts - I'm seeing LEDs light up even in bypass mode, nothing is making any sense. Got any clues? I put it right back in the CAPI rack and it worked like a charm.....?

 

[RandyBeast]

jsteiger or anyone who has experienced this situation with the XFMR

TP9 = -10.05

TP10 my Voltage is all over the place and slowly drops. My LEDs will flicker on and off as the voltage bounces up and down. after adjusting RV1. my voltage will bounce around and eventually go from 2.48V back down to 1.68V any Idea which component went bad on me?

I also notice my reference voltages for my comparators are .03V higher than suggested.

11=2.53V
10=2.48V
and so on.

Any help would be great. I have a good Meter on another build and the voltage does the same even when swapped. so I know the problem is on the main PCB.

Thanks

 

[jsteiger]

jsteiger or anyone who has experienced this situation with the XFMR

TP9 = -10.05

TP10 my Voltage is all over the place and slowly drops. My LEDs will flicker on and off as the voltage bounces up and down. after adjusting RV1. my voltage will bounce around and eventually go from 2.48V back down to 1.68V any Idea which component went bad on me?

I also notice my reference voltages for my comparators are .03V higher than suggested.

11=2.53V
10=2.48V
and so on.

Any help would be great. I have a good Meter on another build and the voltage does the same even when swapped. so I know the problem is on the main PCB.

Thanks

I'd start by replacing the transistor that you had backwards before with a fresh one. Could also be a cold solder joint(s) somewhere.

 

[RandyBeast]

I'd start by replacing the transistor that you had backwards before with a fresh one. Could also be a cold solder joint(s) somewhere.

I thought that too, however, I replaced the meter board with a good meter board and no change. so I know it's not the transistor

 

[jsteiger]

I thought that too, however, I replaced the meter board with a good meter board and no change. so I know it's not the transistor

If it was fine and is now intermittent...most likely = bad solder joint(s) somewhere.

 

[rasalrew]

Hey guys.

I was in a session recently and my FC526-XFMR started acting strangely. Before then it was used very often.

When the incoming signal reaches a certain volume, the device cuts out with a loud clipping *BLIP*, and then the signal gets very quiet and distorted. I believe bypass works fine, at least the few times I tried it. I've noticed if I flip the GR switch back and forth a few times I can repeat the process, and get the same results of clipping followed by a low distorted signal, The issue happens whether or not GR is activated. I left for holiday a day after so haven't investigated much beyond what's mentioned above. hoping to do some testing when I'm back.

I'm going to re-flow some solder joints, I have a feeling maybe an IC is burnt/damaged on the GR circuit. I've checked the opamps by replacing one at a time with a spare I have & they all seem fine. Anyone ever come across a similar issue?

 

[jsteiger]

Hey guys.

I was in a session recently and my FC526-XFMR started acting strangely. Before then it was used very often.

When the incoming signal reaches a certain volume, the device cuts out with a loud clipping *BLIP*, and then the signal gets very quiet and distorted. I believe bypass works fine, at least the few times I tried it. I've noticed if I flip the GR switch back and forth a few times I can repeat the process, and get the same results of clipping followed by a low distorted signal, The issue happens whether or not GR is activated. I left for holiday a day after so haven't investigated much beyond what's mentioned above. hoping to do some testing when I'm back.

I'm going to re-flow some solder joints, I have a feeling maybe an IC is burnt/damaged on the GR circuit. I've checked the opamps by replacing one at a time with a spare I have & they all seem fine. Anyone ever come across a similar issue?

Possibly bad solder joints. I would also look at the DTO5. Maybe misplace resistors on there that have created problems. Could be solder joints on the DTO5. Not likely an IC opamp.

 

[Dr.Weezil]

Please disregard my previous post; I was a bonehead and figured out how to properly get the correct levels for calibration into my two FC526s. Took me a while, eh? Of the two, the first went fine and is working as it should. The second is giving me trouble. It appears I have an issue with the audio path per the calibration guide and test point guide. TP1 is measuring at 5.0mV, with TP2 and TP3 measuring at 62mV and 772mV, respectively. I have swapped out the 2520 for the one from the other module and I get the same results. Looks to be about 1.2dB lower than it should be.

I saw that another poster had an issue with his interface; however, I was able to successfully calibrate the other module. Where should I be looking for problems in the build and are there any other things I should look out for? I'm assuming the follower after the input transformer?

Thanks again.

EDIT: I see earlier responses about testing TP1. I will check and report back.

The other issue is that the bias trimmer is not having any effect on output. Again, I’ll check to verify. Looks like I’m going through all the resistors.

 

[SKJGProject]

Soundwise what‘s the difference between the old and the new xfmr version?