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Nibbles
Copper Member
USA
31 Posts |
 Posted - 11/13/2009 : 09:19:29
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I just sold one of these on ebay. The buyer says the volume pot is scratchy and the volume cuts in/out when the control is moved.
I tested all controls before I shipped it and they were fine. Is this just a matter of cleaning the pot or possibly a symptom of something more serious?
I'm wondering if it took a hit during shipping. |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 11/13/2009 : 09:57:35
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Tell them to check the 12ax7 tube inside...it's could be the tube is loose,on the way out or got a knock during shipping ..the symptoms my Musicman amp had were the same and it needed a cap jop but can't understand how the Blackstar could be like that already as the musicman is over 30 years old,when the caps go bad they leak DC voltage onto the pots and you get the 'scratchy' sound and the effect the volume isn't working properly...did you sell it within the US...?..just in case the adapter you sold with it was for 110v and they plugged into a 220v supply like we have in europe they might of blown something inside..... |
Edited by - FRANZONI on 11/13/2009 09:59:33 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/13/2009 : 10:16:58
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I bought a Big muff on ebay about a year ago and had the same problem... seller swears no problem before shipping.
Turned out to be a metal shard had somehow got into the tone pot... probably there all along but the shipping dislodged it.
Contact cleaner shifted it and it was fine. I know what it actually was because I dismantled the pot to see (for no reason other than my curiosity).
MIGHT be something similar?
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 11/13/2009 : 10:26:11
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I had a new Blackstar HT-Drive a month or so, it scratched on the drive pot. Maybe they don�t use quality pots???
Edit:It could have been the volume pot, not sure  |
Edited by - Goran on 11/13/2009 13:02:11 |
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Ollie
Gold Member
United Kingdom
729 Posts |
Posted - 11/13/2009 : 10:58:10
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| I use a DISTX (and love it) and if i adjust the volume it crackles slightly now and again. I don't adjust the volume much so it doesn't bother me much , but if anyone has a solution that would be nice |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 11/13/2009 : 11:13:37
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By the way, I have had 4-5 different Boss BD-2 and all of them crackled when the drive knob was/is used.
One of Zvex pedals has a knob called Crakle OK, or something like that.
So it�s in the construction in some cases.
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 11/13/2009 : 12:38:31
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| From the responses it looks like a sub standard pot or maybe the caps aren't as good as they could be ... |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/13/2009 : 16:02:49
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The "Crackle" pot mentioned illustrates an interesting "design feature".
In electroincs design, if a pot is put into a "DC signal path", it will crackle. Forever. It isn't a fault, it's an artifact of the "graininess" of the physical construction of the pot.
In nearly every design (maybe 99+%) the designer uses GREAT care to not put any DC through a pot to avoid this crackle (it's an ongoing design challenge). But sometimes you just can't get away from it like in the Krackle pot... this particular pot is placed in the circuit specifically to adjust the DC-bias so inherantly it must have DC in it. Hence the crackle.
Most times though, it's a fault - in 90% of the cases a squirt of Contact Cleaner will fix it (unless the pot is sealed in which case it may need replacement).
/<pontificate>
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zerksies
Double Platinum Member
USA
3406 Posts |
Posted - 11/14/2009 : 03:57:59
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| The pot really just needs to be cleaned |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 11/19/2009 : 18:46:54
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I wish people would post back and let us know how they fixed the problem.... .... |
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Nibbles
Copper Member
USA
31 Posts |
Posted - 11/28/2009 : 11:36:38
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| The guy that bought my pedal took it apart and sprayed some contact cleaner and that didn't resolve the problem. He planned to take it in for repairs and I haven't heard back from him. If the buyer lets me know how he resolved the issue, I will post back. |
Edited by - Nibbles on 11/28/2009 11:37:48 |
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Ollie
Gold Member
United Kingdom
729 Posts |
Posted - 12/13/2009 : 20:24:37
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Would like to know more about this, my blackstar htdistx volume pot is starting to piss me off now  |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 12/13/2009 : 21:36:58
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| starting to sound like a batch of them have some sort of manfacturing error or some bad parts inside.... |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/14/2009 : 15:58:11
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Hi Guys
Anyone here seen or have the schematics for these?
It would be interesting to see why they are staring to experience this noisy Crackly pot issue.
Are there similar comments/posts on any other forums?
Or has anyone actually contacted the manufactures & asked how/what they are doing to resolve this problem.
I would be keen to hear the official response.
Regards Dr. Bob  |
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Blackstar HTDISTX
