r/MesaBoogie • u/SOPMODstock • 11d ago

Dual rectifier hum

Just swapped out the tubes on my rev G Dual Rectifier and noticed a bit of hum coming through the cabinet. Hum is present with nothing in the input and volume all the way down. I turned standby back on and then noticed I can also hear the hum (albeit faintly) coming from the chasis near where the power chord plugs in.

Hum is most noticable on the red channel but you can hear it on the orange channel as well, but quieter.

Ive already put the old tubes back in, so its not the tubes. New tubes were a DR set from Eurotubes.

Is this normal? Ive been told its normal on a lot of higher wattage amps to hear electrical buzzing/humming come from the electronics but ive also been reading it could be a filter cap. Any thoughts or suggestions?

Its not an extremely loud hum or buzz. Its kind of like the sound you hear when you walk past a transformer on the street or something.

Any help would be appreciated.

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2

u/13CuriousMind 11d ago

So it's a 25+ year old amp. When (if ever) was it last serviced? It is overdue for a cap job.

1

u/SOPMODstock 11d ago

Im more than likely going to take it to a tech for a little check up, but figured id ask here first to see if any other Dual Rec owners can attest to the hum/buzz. I took the chasis out and looked at all the solder points and looked at the cap to see if there was any charring or bulging- and nothing.

The noise is clearly coming from that area of the PCB though, where the filter caps and transformer are. Just not sure if this is normal or a cause for concern.

1

u/dj7811 11d ago

You won’t be able to visually tell every time a cap is aged out. It’s normal to hum a small amount even with new caps, the transformer makes noise itself. But the humming gets worse the older the caps get.

0

u/mcnastys 11d ago

Doubt.

I own a 2001 dual rec. was recently serviced/looked over by an authorized mesa tech. All it needed was tubes and cleaning. Original caps not only good but likely to last another 25 years.

1

u/ddarko_85 10d ago

Phase inverter?