Hi all, I am new here and Thought I would get some help from the Boogie players here on the forum before wasting money. I have a mesa single rectifier and may have a problem , it has an awful noise with nothing going through it at all. The noise sounds like static noise like you would get from a TV channel that doesn't come in. The noise is there no matter what the settings are on the amp, but is not there with the output volume off. Today the amp started doing something new. Now after its been on a while it will start making a popping sound and if you knock on the front where it says rectifier it will make a helicopter noise and the power tubes flash like crazy. Tubes are all brand new Mesa EL34's and 12AX7's just put in 2 days ago. All help and advice is much appreciated. Thanks.
Single Rec Noises
- Thread starter srv3089
- Start date
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I am not 100% sure about this but I think the single rec does not have a el34/6l6 bias switch like dual recs, and it takes 6l6 power tubes stock so you may have the wrong tubes in there.
Are the tubes arcing or glowing super bright (not the usual orange glow)?
Are the tubes arcing or glowing super bright (not the usual orange glow)?
DISCLAIMER: If you are not comfortable working on a tube amp, there are voltages inside that can kill you. Take it to a professional. Just sayin.
Now, you said when you bump it, it makes noise, that leads me to believe you have a bad P/I tube (V5 plus the behavior of the power tubes has me concerned). Russian Mesa 12AX7s are not good in this position. A bad P/I tube will destroy a good set of Power Tubes.
With the tube guard removed, and the metal shield caps removed from the pre-amp tubes. Turn the amplifier on, and off of Standby. Be careful NOT to touch the power tubes when the amp is on, the get VERY hot. Then, with the end of a pencil (eraser equipped
) tap each pre-amp tube with the pencil. If it makes noise through the speaker, the tube is microphonic and should be replaced. You can also tap your power tubes, but be gentle, I have seen bad tubes pop with a slight tap on the glass envelope.
Try rolling a few of your pre-amp tubes from V5. This is the P/I stage that controls your power tubes, I would swap it with V4 (FX loop) and see if there is any change.
It is not uncommon for Mesa 12AX7s (or any tube) to go bad quickly in the P/I position. It is also not uncommon for them to be bad from the get go.
Make sure your bias switch is set correctly. Having it wrong will chew up a pair of EL34s really quick.
Now, you said when you bump it, it makes noise, that leads me to believe you have a bad P/I tube (V5 plus the behavior of the power tubes has me concerned). Russian Mesa 12AX7s are not good in this position. A bad P/I tube will destroy a good set of Power Tubes.
With the tube guard removed, and the metal shield caps removed from the pre-amp tubes. Turn the amplifier on, and off of Standby. Be careful NOT to touch the power tubes when the amp is on, the get VERY hot. Then, with the end of a pencil (eraser equipped
) tap each pre-amp tube with the pencil. If it makes noise through the speaker, the tube is microphonic and should be replaced. You can also tap your power tubes, but be gentle, I have seen bad tubes pop with a slight tap on the glass envelope.Try rolling a few of your pre-amp tubes from V5. This is the P/I stage that controls your power tubes, I would swap it with V4 (FX loop) and see if there is any change.
It is not uncommon for Mesa 12AX7s (or any tube) to go bad quickly in the P/I position. It is also not uncommon for them to be bad from the get go.
Make sure your bias switch is set correctly. Having it wrong will chew up a pair of EL34s really quick.
bendo said:DISCLAIMER: If you are not comfortable working on a tube amp, there are voltages inside that can kill you. Take it to a professional. Just sayin.
Now, you said when you bump it, it makes noise, that leads me to believe you have a bad P/I tube (V5 plus the behavior of the power tubes has me concerned). Russian Mesa 12AX7s are not good in this position. A bad P/I tube will destroy a good set of Power Tubes.
With the tube guard removed, and the metal shield caps removed from the pre-amp tubes. Turn the amplifier on, and off of Standby. Be careful NOT to touch the power tubes when the amp is on, the get VERY hot. Then, with the end of a pencil (eraser equipped
Try rolling a few of your pre-amp tubes from V5. This is the P/I stage that controls your power tubes, I would swap it with V4 (FX loop) and see if there is any change.
It is not uncommon for Mesa 12AX7s (or any tube) to go bad quickly in the P/I position. It is also not uncommon for them to be bad from the get go.
Make sure your bias switch is set correctly. Having it wrong will chew up a pair of EL34s really quick.
I have done all this and didn't make a diffierence. I can tap on the tubes all I want and it will not make any of the noises, all you hear is the tap itself. It will either helicopter on its own or just knock on the front of the amp where it says rectifier. This is the strangest acting amp I have ever had, its like its haunted or something. The way I found out about the helicopter noise was by knocking all over the amp to see if that would stop the static noise that I get but all I got was the helicopter noise, It will go away if you turn the output knob off but the minute you turn it back up and knock on it its back when it makes this noise is when the power tubes will flash, they flash right along with the noise. Like I said Haunted. Thanks. Any and all help is appreciated and welcome.
Thanks for all the help. It is going in to the shop next week. I hope its nothing too seriously wrong with it. I also love my single the best sounding amp I have ever owned. This is an off topic question but has anybody really noticed a difference in tone between tube rectifiers and diodes? Just wondering a friend of mine has a triple and sound wise I hear no difference but thought maybe some that does could let me know what to listen for. Thanks.
JonCurcio said:
Thanks for that link it kinda cleared things up a little, but if going by that article then having a mesa rectifier and using rectifier tubes is costly in tube replacement and doesn't sound as good as diode and apparently pointless. How does that make any sense? Does Mesa know this? I guess its all up to the player to decide. Very confusing one disagrees with the other, a never ending battle in guitar amp industry. Thanks for all the help.
srv3089 said:
Tube Rectifiers add a certain "sag" to the tone. It's hard to describe, but there is a noticeable difference between using the 2.
Tube rectifiers don't tend to do high gain we precisely as a silicon rectifier.
While the 50s and 60s were tones were all tube rectifiers for the most part. Silicon rectifiers started showing up in the late 60s.
When playing blues or jazz, tube rectifiers color the tone very nicely. Classic rock too.
Basically, there are many times when a tube rectifier is desirable. The bigger rectos have both, and are switchable.
deeman
Well-known member
I play at lower gain in an indie/alt-rock group and use the tube rectifier
Third Age Amps
Well-known member
I've never heard of a PI taking out power tubes before ... Where did you get that info? I'm always on the lookout for troubleshooting info!
