New Tubes then a loud Hum!?

Talk about tubes and their effect on your tone

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TremoJem
Mark III
Posts: 421
Joined: Wed Mar 02, 2011 11:42 am

New Tubes then a loud Hum!?

Post by TremoJem » Mon May 23, 2011 6:00 am

I replaced the output tubes with vintage good tubes and preamp tubes with all new ones.

As soon as I switched the standby on I got a Loud Hum or short that sounded kinda like an unplugged guitar jack that was shorted.

This noise was not affected by any changes to the amp controls and so I immediately switched it off and made adjustments while in standby and continued to troubleshoot.

I gave up and the next morning it was gone.

Any suggestions?

Also: I have a ringing when playing. I think that is a "micro phonic" preamp tube, so I will start the swapping procedure to move that tube to a less sensitive spot in the chain.

All suggestions are appreciated and thanks for reading.
Ibanez Jem 7VWH > Bad Horsie II Wah > Radial JX-2 ABY Switch > Two Tremoverb Combos
Mesa Channel Switch DTDP & Mesa FXLoop Switch DTDP
TC Electronic G-Major & Ernie Ball Volume Pedal & Behringer FCB 1010
Assorted Tubes
Series FXLoop

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Rampage
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Location: Phoenix, AZ

Re: New Tubes then a loud Hum!?

Post by Rampage » Mon May 23, 2011 4:21 pm

Excessive humming can definitely be the sign of a bad tube, and the ringing definitely sounds like something is microphonic. Try the old pencil eraser trick: With the amp powered up and in play mode, gently tap each tube with the eraser. If one causes ringing, it is likely microphonic and should be replaced.

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stokes
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Re: New Tubes then a loud Hum!?

Post by stokes » Mon May 23, 2011 10:13 pm

The ringing is most likely a preamp tube,check as described.Anytime you get noise that is not affected by the controls,it is from the output section,the controls are all in the preamp.You say you "replaced the output tubes with vintage good tubes".Are you sure they are matched and in the proper bias range?Tubes that are too far out of "match" can cause hum.Tubes that are biased too hot will cause a loud hum as well.

TremoJem
Mark III
Posts: 421
Joined: Wed Mar 02, 2011 11:42 am

Re: New Tubes then a loud Hum!?

Post by TremoJem » Tue May 24, 2011 5:38 am

The tubes are correct, as I got them from Mesa for the amp specifically.

I rolled them years ago and saved them for spares.

The hum is gone and has not returned.

Thanks all.
Ibanez Jem 7VWH > Bad Horsie II Wah > Radial JX-2 ABY Switch > Two Tremoverb Combos
Mesa Channel Switch DTDP & Mesa FXLoop Switch DTDP
TC Electronic G-Major & Ernie Ball Volume Pedal & Behringer FCB 1010
Assorted Tubes
Series FXLoop

TremoJem
Mark III
Posts: 421
Joined: Wed Mar 02, 2011 11:42 am

Re: New Tubes then a loud Hum!?

Post by TremoJem » Tue May 24, 2011 5:43 am

I will post results from my findings.
Ibanez Jem 7VWH > Bad Horsie II Wah > Radial JX-2 ABY Switch > Two Tremoverb Combos
Mesa Channel Switch DTDP & Mesa FXLoop Switch DTDP
TC Electronic G-Major & Ernie Ball Volume Pedal & Behringer FCB 1010
Assorted Tubes
Series FXLoop

TremoJem
Mark III
Posts: 421
Joined: Wed Mar 02, 2011 11:42 am

Re: New Tubes then a loud Hum!?

Post by TremoJem » Wed Aug 31, 2011 9:13 am

Left this one hanging...really sorry.

It was a bad preamp tube.

Replaced and no more problems.
Ibanez Jem 7VWH > Bad Horsie II Wah > Radial JX-2 ABY Switch > Two Tremoverb Combos
Mesa Channel Switch DTDP & Mesa FXLoop Switch DTDP
TC Electronic G-Major & Ernie Ball Volume Pedal & Behringer FCB 1010
Assorted Tubes
Series FXLoop

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