Tube amp service question

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Thurgood

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Hello All! I have a Fender DRRi that has started to emit a low level scratchy noise when no input present (or input present) and also regardless of volume setting. It is not loud just a background noise. Kinda like a noise you make when you toch the open end of a cable. Ya know hissy scratch. Tube issue? Cap issue. the amp is only two years old (and is due for a new set of power tubes as one is getting a bit microphonic) (note these are the original tubes). Also you hear the normal noise floor of the amp but this rides on top and is intermittent. Any suggestions appreciated. I am in a position to return some unused el 84's for two 6v6's so new power tubes not a problem.
 
I myself if you dont play much then re tube once a year (power and pre) if you play a lot every 6 months. i follow this just to be on the safe side.
 
Thurgood said:
Hello All! I have a Fender DRRi that has started to emit a low level scratchy noise when no input present (or input present) and also regardless of volume setting. It is not loud just a background noise. Kinda like a noise you make when you toch the open end of a cable. Ya know hissy scratch. Tube issue? Cap issue. the amp is only two years old (and is due for a new set of power tubes as one is getting a bit microphonic) (note these are the original tubes). Also you hear the normal noise floor of the amp but this rides on top and is intermittent. Any suggestions appreciated. I am in a position to return some unused el 84's for two 6v6's so new power tubes not a problem.
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Your problem may be coming from a poor connection in the amp, a cold solder joint, a bad tube. To isolate the problem, you can troubleshoot. WHile the amp is turned on, carefully rock the tubes. Does this cause your intermittent noise? If yes, you can try removing the offending tube and cleaning the pins with denatured alcohol on a q tip. If this doesn't help, try replacing that tube or, if it is a power tube, replace the pair. If this doesn't help, try banging the top of the amp. Does this make the noise happen or stop? If yes, you may have a bad solder joint in the amp that will need to be replaced. Unless you are familiar with tube amps and the lethal voltages inside, bring it to a tech.

If it is not a tube issue, your amp may be under warrantly and it would be worth it to have it looked at by an authorized warranty repair place.

Good luck with your amp.

Paul
 
Thanks guys. I have had other amps with "grumbling amp" syndrome. I'll try the tubes first. PS I do own a Mesa Boogie. When it is in use my neighbors grumble. The amp on the other hand........sings.
 
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