crackly knobs

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Kwote
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crackly knobs

Post by Kwote » Mon Nov 26, 2007 12:43 am

i've noticed lately that i get some crackly kinda sounds when i turn the pot A up on my dual linear VCA. i'm guessing there's a simple way to clean it right?
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Post by consumed » Mon Nov 26, 2007 11:55 am

does the crackly happen even if you have nothing plugged into the input?
or does it happen only with some input?

if its a pot problem, i think (but not sure) that the panasonic pots blacet uses are sealed, meaning you'd have to replace the pot. someone correct me if im wrong.

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Post by Kwote » Mon Nov 26, 2007 12:07 pm

nope just when i had something plugged in. but it's kinda funny cuz last night i patched it up and there wasn't a bit of an issue. guess it depends on the patch. if i isolate it somehow i'll see if it's worth trippin on.
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Post by consumed » Mon Nov 26, 2007 2:18 pm

test it with a sin wave (no high freq content).
its also possible that working it out cleaned it up--sometimes that happens.
or you could have been overloading your input device that was eating the modular output...dunno.

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Post by Kwote » Mon Nov 26, 2007 2:51 pm

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Last edited by Kwote on Thu Jan 10, 2008 1:48 pm, edited 1 time in total.
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Post by Kwote » Thu Nov 29, 2007 11:50 am

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Last edited by Kwote on Thu Jan 10, 2008 1:48 pm, edited 1 time in total.
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Post by Kwote » Thu Jan 10, 2008 1:47 pm

okay it appears i was too faithful. pot A on the linear VCA is still having crackly issues. this time i know it's not an overload because i only had one signal going into the vca. Pot B is 100% clean even when fully open. Pot A is a mess crackles every few millimeters and even cuts the sound out sometimes.

what do i do? :?
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Post by consumed » Thu Jan 10, 2008 2:07 pm

contact blacet directly.

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Post by Muff Wiggler » Thu Jan 10, 2008 3:28 pm

- first make SURE it's not a bad cable or a bad jack - which could easily cause this (yes even just presenting when you turn the knob)

- if you can eliminate the above, there's most likely something up. but i have like 80 Blacet modules, and over half of them are used, and a lot are many years old - and I don't have scratchy pots. the panasonic pots are ALMOST completely sealed, there's just the tip of the axis that protrudes through the back, you can see it. the gap around that is too small even for any considerable dust, these pots shouldn't be a problem.

- although all my pots are good, when the pot is unused for a long time, it can be scratchy at first. a good few of my used modules arrived with pots that were scratchy at first. after turning the pot completely back and forth a couple hundred times, they were no longer scratchy at all

- believe it or not, it could be a bad IC causing this. This happened to an EG1 of mine, because I fried an IC while modding it :oops: If you have another Dual Lin VCA, swap the ICs between them. Luckily John sockets all his ICs, so they are easy to swap.

(Actually, full story, i thought I friend an IC and replaced it, but i never friend an IC - instead a little 'splash' of flux from my soldering contaminated the board, causing a short, which presented as scratching when I turned a pot. When the replacement IC failed to solved the problem, I freaked, inspected the board, saw the flux, picked it off with my finger, and the module was 100% again. So another point - you could have something contaminating the board and causing a short, so inspect your board as well)

- worst case, contact John and he will set you up for a repair. I've had two modules sent to him for repair in the past, both were returned with INCREDIBLE speed, one was free and the other was $25 (or $29 perhaps, no matter). I believe that is the going rate for ANY repair job from Blacet, however don't quote me on that. In any case John will take EXCELLENT and FAST care of you as a repair customer.

- good luck!

- i'm sure you know this, and I know its disappointing when a module doesn't work right, it's happened to me too. but it's always good to remember that 'it's just a module' and they can swap out of your system so easily, and it WILL get fixed, and it's really not the end of the world in any respect at all :D

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Post by Kwote » Thu Jan 10, 2008 4:23 pm

i don't think it's a bad cable as i've done many patches since the problem first arrived with many different cables. the jack is a possibility but i wouldn't have any clue what to do about that.

i use it pretty regularly so i'd imagine the knob has been turned back forth plenty but i'll put it under rigorous scrutiny tonight.

i'm still very lame at understanding the whole IC thing. honestly i don't even know what an IC is. lol.

i know i'm way overdue for learning all these things but i guess having a problem is all that has prompted me so far. i'd do diy if i didn't live in a small ass apartment though. so i'm sure at some point everything will make a lot more sense.

i spoke with John. he set me up for a free repair since the module is less than a year old. i'll probably send it out monday if i still can't troubleshoot it.

thanks Muff. and thanks for the afterthought as well. i'm just a little bummed because i only have the one vca. so no proper volume envelopes for the time being if i ship it out. it's not a big deal to me but i am in the middle of working on an EP as well as a little bit of soundtrack work so it's sort of something to slow me down. hopefully i can complete the EP and soundtrack stuff by the end of the weekend so getting it repaired won't be a thorn in my side.

right on!!!
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Post by Chuck E. Jesus » Thu Jan 10, 2008 5:26 pm

i don't know much about sealed pots, but it won't hurt to spray a little Radio Shack contact cleaner and twist the knob back and forth a few times...just make sure it's powered down and let it dry a few minutes (says how long on the can)...i've had very good luck with the stuff...

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Post by Muff Wiggler » Thu Jan 10, 2008 6:28 pm

ICs are the black chip components (in the black chip socket components) on the circuit board, they look like little computer chips, or little alien centipede robots with their little grey legs

it stands for Integrated Circuit

and John will be really fast with your repair, i'm sure

bummer though

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Post by Kwote » Thu Jan 10, 2008 6:28 pm

i've got something similar to the contact cleaner called caig de-oxit or something like that. might have to give that a shot if muff's suggestions don't work out.

i sorta passed through your idea in my head as i used to have to deal with this kinda stuff on my mixer's fader(being a dj and all).
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Post by consumed » Thu Jan 10, 2008 6:39 pm

since the pots are almost sealed, there will probably be no benefit in spraying de-oxit on it, except to make some mess. deoxit is great in sliders on mixers or sometimes on jack contacts that might be a bit dirty, or in open-frame pots.

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Post by Kwote » Thu Jan 10, 2008 7:00 pm

consumed wrote:since the pots are almost sealed, there will probably be no benefit in spraying de-oxit on it, except to make some mess. deoxit is great in sliders on mixers or sometimes on jack contacts that might be a bit dirty, or in open-frame pots.
i sorta had a feeling that's what someone would say. i was actually waiting just for a post like yours. haha.

but yeah i think just the fact that blacet was so quick to respond and all he said was send it over makes me think it wouldn't hurt to just go ahead and push it on through. i got a couple days to sort it out before it heads over to Blacet Country.
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Post by Chuck E. Jesus » Fri Jan 11, 2008 7:29 am

consumed wrote:since the pots are almost sealed, there will probably be no benefit in spraying de-oxit on it, except to make some mess. deoxit is great in sliders on mixers or sometimes on jack contacts that might be a bit dirty, or in open-frame pots.
like i said, i know little about sealed pots...but Muff mention a small opening, i'm just saying it might be worth a shot...

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Post by Kwote » Fri Jan 11, 2008 12:11 pm

okay! after an hour of constant twisting and multiple patches utilizing the VCA i've determined it's most likely a bad patch cable(s). i haven't determined which one yet as everything i tested last night was extremely clean. i mean impeccably. looks like i wrote john for nothing.

now i just gotta keep my ears wide open for which cables are the culprits. those little bastards :evil:

but yeah i have a pretty strong feeling that's what's wrong. god this has been weird. hehe. but a cool sidenote is upon doing this all i learned some really great ways to attenuate my cv's. that's what i love about modulars. i'm not even trying to do anything but isolate my problem and yet i still manage to learn and have fun in the process.
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Post by Muff Wiggler » Fri Jan 11, 2008 12:54 pm

hehehe modulars are ALWAYS fun 8)

that's good news. Honestly, my first thought was "cables or jacks". cables can be really sneaky!

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