Mesa: bias question

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Metal1977

Metal1977

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I would like to ask the experts around here. I bought a Dual Rectifier Rev G that sound insane around 9 o'clock and a little more but when i'm cranking it louder (band level) it start to compress and i don't like the sound it produce. It doesn't need that much to be perfect.

If i do a bias mod and i bias the amp a little colder will it help my situation? Will it allow me to crank it a little louder before that compression occur?

My power tubes are SED winged C 6l6 matched set for the Rectifier. Keep in mind that i want to keep this amp, not buying a Triple Rec.

Thanks!

Chris
 



Try dialing back the preamp gain and/or using a 5751 preamp tube in V-2 slot.
 
The sound you don't like is coming from the power tubes. I have the same problem with my triple when it gets loud and the power tube compression comes into play. I have to use the rectifier tube setting to get the bounce back.

Do you know what the bias is on the tubes you are using?
 
Yes, you know what i'm talking about. When i order those tubes i mention it was for a dual rectifier, it's written 18 on the boxes. Did i made a mistake, should i have ask for late breakup? I didn't mess with the rectifier tubes switch to much, it's on diode all the time, i thought it would be worst.
 
Are you using tube, or silicone rectfier? The Silicone rectifier problem should stay more controlled at higher volume. Also what mode are you on? If I remember right I think red mode has less feedback in the power section, maybe try to get your sound on the orange mode, and less gain, and less bass as the volume goes up
 
I play on the red channel modern bold and diode rectifier with a maxon od808. I don't like the orange that much. I tried backing up the gain and bass as i go into power amp saturation but it doesn't solve the problem. I will try the tube rectifier to see.
 
psychodave":k62wvspd said:
The sound you don't like is coming from the power tubes. I have the same problem with my triple when it gets loud and the power tube compression comes into play. I have to use the rectifier tube setting to get the bounce back.

Do you know what the bias is on the tubes you are using?

You where right, when i switch to rectifier tubes setting, the sound dropped a little but i was able to go higher with the master volume. The rectifier tubes smooths out the signal and make the power tube compression less drastic and blend easier with the sound. My bad, i should have tried it before posting about it.

Problem solved, thanks!
 
Metal1977":1qekl5qf said:
psychodave":1qekl5qf said:
The sound you don't like is coming from the power tubes. I have the same problem with my triple when it gets loud and the power tube compression comes into play. I have to use the rectifier tube setting to get the bounce back.

Do you know what the bias is on the tubes you are using?

You where right, when i switch to rectifier tubes setting, the sound dropped a little but i was able to go higher with the master volume. The rectifier tubes smooths out the signal and make the power tube compression less drastic and blend easier with the sound. My bad, i should have tried it before posting about it.

Problem solved, thanks!
Thats called "sag". Tube rectifiers create "sag".
 
Chester Nimitz":2mucv2w5 said:
Metal1977":2mucv2w5 said:
psychodave":2mucv2w5 said:
The sound you don't like is coming from the power tubes. I have the same problem with my triple when it gets loud and the power tube compression comes into play. I have to use the rectifier tube setting to get the bounce back.

Do you know what the bias is on the tubes you are using?

You where right, when i switch to rectifier tubes setting, the sound dropped a little but i was able to go higher with the master volume. The rectifier tubes smooths out the signal and make the power tube compression less drastic and blend easier with the sound. My bad, i should have tried it before posting about it.

Problem solved, thanks!
Thats called "sag". Tube rectifiers create "sag".

:thumbsup:
 
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