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PostPosted: Sun Mar 29, 2009 7:48 pm 
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Bottle Rocket

Joined: Sun Mar 29, 2009 7:41 pm
Posts: 5
I have a DC-5 that has a continuous loud hum on the clean channel only. The hum is there even without a guitar plugged in. The lead channel is fine. I started to notice some distortion on my clean channel and then realized how much louder the hum was on the clean channel as opposed to the lead channel.

anyone have any ideas ?


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PostPosted: Mon Mar 30, 2009 8:08 am 
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Mark IV

Joined: Tue Oct 30, 2007 10:34 am
Posts: 594
Location: Dallas, TX
Have you changed your tubes lately? I had a similar problem which turned out to be a noisy 12ax7 in V1 which is the first lead and rhythm stage. Some of the quietest preamp tubes seem to be JJs. To verify the suspect tube was bad I put it in another amp that is always very quite and could detect a little noise. Do you know if the amp has ever been recapped?

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DC-5 head, 2x12 Stagecraft w/EVM12Ls, 1x12 Stagecraft w/EVM12L, Digitech GSP1101/Control 2, GT-100


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PostPosted: Mon Mar 30, 2009 8:14 am 
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Joined: Mon Jun 04, 2007 7:58 am
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Location: Greenville. SC
This is another case where the clean channel is the offending channel and the Lead channel is fine. That to me is strange. Another user had the same problem and ended up changing their settings to cope. If you don't have JJs in there already then definitely give that a try! They are the quietest tubes for a DC and sound excellent.

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Mark V:25 | Mini Rectifier 25 | Mini Rec 1x12 | Fractal Audio FX-8
'06 EBMM JP6 (Mystic Dream) | '15 Epi ES-339 PRO (Cherry) | '11 PRS SE245 (Tobacco Sunburst)
'05 PRS SE Soapbar II (Vintage Cherry) | '92 Peavey Predator USA (Custom)


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PostPosted: Mon Mar 30, 2009 10:00 am 
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Bottle Rocket

Joined: Sun Mar 29, 2009 7:41 pm
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The amp has not been recapped. I was considering getting new tubes but was not sure if this would help since my problem was with only the clean channel...I am pretty ignorant when it comes to this stuff.

I will probably order some tubes and see if that helps. Thanks !


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PostPosted: Mon Mar 30, 2009 10:10 am 
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rbtodd wrote:
The amp has not been recapped. I was considering getting new tubes but was not sure if this would help since my problem was with only the clean channel...I am pretty ignorant when it comes to this stuff.

I will probably order some tubes and see if that helps. Thanks !


It's almost always the first step in troubleshooting noise issues with a tube amp.

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Mark V:25 | Mini Rectifier 25 | Mini Rec 1x12 | Fractal Audio FX-8
'06 EBMM JP6 (Mystic Dream) | '15 Epi ES-339 PRO (Cherry) | '11 PRS SE245 (Tobacco Sunburst)
'05 PRS SE Soapbar II (Vintage Cherry) | '92 Peavey Predator USA (Custom)


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PostPosted: Tue Mar 31, 2009 5:06 pm 
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Bottle Rocket

Joined: Sun Mar 29, 2009 7:41 pm
Posts: 5
well, got new tubes (JJ's) and still have the noise problem on the clean channel. Not really sure where to go from here. If anyone has any ideas, please let me know. Thanks !


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PostPosted: Tue Mar 31, 2009 7:52 pm 
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rbtodd wrote:
well, got new tubes (JJ's) and still have the noise problem on the clean channel. Not really sure where to go from here. If anyone has any ideas, please let me know. Thanks !


What are your settings?

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Mark V:25 | Mini Rectifier 25 | Mini Rec 1x12 | Fractal Audio FX-8
'06 EBMM JP6 (Mystic Dream) | '15 Epi ES-339 PRO (Cherry) | '11 PRS SE245 (Tobacco Sunburst)
'05 PRS SE Soapbar II (Vintage Cherry) | '92 Peavey Predator USA (Custom)


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PostPosted: Tue Mar 31, 2009 8:55 pm 
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Bottle Rocket

Joined: Sun Mar 29, 2009 7:41 pm
Posts: 5
The only settings that are not at 0 are the gain, master for the channel, and the overall volume control. the EQ is disabled and the reverb unit is not connected. The noise is present even at the lowest gain and volume settings.

Hope that answers your question. Thanks !


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PostPosted: Wed Apr 01, 2009 6:55 am 
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Mark IV

Joined: Tue Oct 30, 2007 10:34 am
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Location: Dallas, TX
If I was in your position, and I have been, I would just take it to a good tech and be done with it.

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PostPosted: Wed Apr 01, 2009 7:02 am 
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MJ Slaughter wrote:
If I was in your position, and I have been, I would just take it to a good tech and be done with it.


It sounds like it may have come to this if nothing else has worked. Would certainly save you some time and frustration.

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Mark V:25 | Mini Rectifier 25 | Mini Rec 1x12 | Fractal Audio FX-8
'06 EBMM JP6 (Mystic Dream) | '15 Epi ES-339 PRO (Cherry) | '11 PRS SE245 (Tobacco Sunburst)
'05 PRS SE Soapbar II (Vintage Cherry) | '92 Peavey Predator USA (Custom)


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PostPosted: Wed Apr 01, 2009 8:38 pm 
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Bottle Rocket

Joined: Sun Mar 29, 2009 7:41 pm
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That's what I am going to do. thanks for everyone's response!


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PostPosted: Mon Apr 06, 2009 5:19 am 
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Mark II

Joined: Wed Mar 11, 2009 6:12 am
Posts: 56
Tell us how it goes!!

mine has the same issue. Not really a big deal for me because it's not very noticeable playing


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PostPosted: Sun Apr 12, 2009 7:05 am 
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Joined: Sat Oct 01, 2005 2:27 pm
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Location: Maui Wowee!
Damn! Usually swapping V1 or V4 will do the trick!

It sounds like a bad resistor or a cap job to me.

Make sure you take it to a good tech. I hate those guys who 'Bench Test' the amp instead of simply plugging in a guitar and wailing on it for a while.

Just the same, you might try swapping V1 with V2.
Then, try swapping V4 with V5.
I know it seems silly, but I have had bad tubes right out of the box and even put them in the exact same spot that had a bad tube in it to start with.

Hope this helps!

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