mindcandyman
Member
- Joined
- Sep 4, 2008
- Messages
- 16
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Hey guys I was playing on stage and I noticed when a song ended that there was a buzzing or hissing in my amp that wasn't there before. Normally my amp is dead quiet compared to the other amps. At the beginning of the show my amp was functioning perfectly as well. I thought it was something with the lighting that was putting noise in my amp so I didn't think twice about it. Now when I come home I hear that same hissing and stuff.
Now if I turn the gain all the way up the noise is really really loud. The level of the noise seems to be associated with what gain level I set. I would normally, of course, get some noise when I turned the gain all the way up before but this is far in excess to what I normally hear. With the gain turned all the way up it's just a really loud buzzing.
I can play my guitar through the amp as well but it seems to have much more head room than normal. I am playing with a stock top boost module and it doesn't really get distorted till about 11 or 12 o clock which is not like the top boost module. Normally I can't really get clean tones at all with the top boost.
When I use my voltmeter on the back of the amp...test point #1 reads around 18 mv (normal for RM20B, 15-20 is the standard)...but the second test point only reads around 4 or 5 mv. Does that mean that my 2nd power tube is bad or is about to go bad. The reason I ask this is because I researched this online and I know this kind of noise and such can be caused by preamp tube failure on the module...and also the gain tube (nearest the input) on the amp as well. I don't have the money right now to replace all of the tubes in the amp so I wanted to see what you guys thought.
If it is the gain tube right by the input would I need a tech to replace that for me? I guess all the preamp tubes would need to be replaced by a tech. Thanks for your help I am new to tube amps.
Oh also both power tube lights are glowing in the back. Also I tapped them very lightly with a pencil to see if any strange noises came from them (saw that suggestion on this forum) and no strange noises were heard.
Now if I turn the gain all the way up the noise is really really loud. The level of the noise seems to be associated with what gain level I set. I would normally, of course, get some noise when I turned the gain all the way up before but this is far in excess to what I normally hear. With the gain turned all the way up it's just a really loud buzzing.
I can play my guitar through the amp as well but it seems to have much more head room than normal. I am playing with a stock top boost module and it doesn't really get distorted till about 11 or 12 o clock which is not like the top boost module. Normally I can't really get clean tones at all with the top boost.
When I use my voltmeter on the back of the amp...test point #1 reads around 18 mv (normal for RM20B, 15-20 is the standard)...but the second test point only reads around 4 or 5 mv. Does that mean that my 2nd power tube is bad or is about to go bad. The reason I ask this is because I researched this online and I know this kind of noise and such can be caused by preamp tube failure on the module...and also the gain tube (nearest the input) on the amp as well. I don't have the money right now to replace all of the tubes in the amp so I wanted to see what you guys thought.
If it is the gain tube right by the input would I need a tech to replace that for me? I guess all the preamp tubes would need to be replaced by a tech. Thanks for your help I am new to tube amps.
Oh also both power tube lights are glowing in the back. Also I tapped them very lightly with a pencil to see if any strange noises came from them (saw that suggestion on this forum) and no strange noises were heard.