.50 Caliber + Question

[Thicks88]

Hey there everyone,
I am new to the forum, and also the proud new owner of a 50 Cal+. This is my first mesa, and I am loving it so far. The only problem I have with it is that there is a very slight hum (almost like a static sound) that is present whenever the amp is turned on, and increases as I turn up the master. The hum is present when there is no guitar plugged into the amp also, and I have tried many different outlets in 2 different buildings.

I have already checked all of the tubes, and it doesn't seem to be a tube problem. I have searched some other threads on here, and it seems that nothing that I have read (and already tried) has been a solution. My question is...
Could this possibly have to do with the Filter caps? possibly need to be replaced? I really don't know all that much about the innards of the amp, so I figured I would ask around here.

Thanks for you help

 

[scottcrud]

Welcome aboard. You've just picked up a great amp, especially for High gain, rock and metal applications. If you want to use it for jazz and cleaner applications it works great there as well, it just doesn't do both great due to the shared EQ on both channels. Run your treble at at least 6-8 and bass 1-3 and compensate with the 5 band Graphic EQ.
And as far as Boogies go, the .50Cal+ is one of their easiest amps to use. I recently picked up my second one, and it had a similar hum going on. I sent mine to fellow forumite "MonstaTone". He went through the entire amp, fixed broken solder joints, replaced the filtercaps, gave it an over all tune up. And did another mod for me, my amp sounds like a brand new amp and should outlast me!
Remember, filter caps are designed to last 15-20 years, I'm guessing your amp is at least 20 years old. Turn your amp over and look at the chassis, somewhere there will be a year and month written in black marker. i.e. 8/89. Hope this helps. Also, you might want to pm MonstaTone, he can help you out for sure.

Scott

 

[stratele52]

If you turn the volume and the hum is louder; this is not a filter caps problem. Filter caps problem give the same amout of hum at "0" volume or at max volume.

You said you check the tube. how do you do that ? put new tubes in or use tubes tester ?

What I suggest you should do;

Remove the first preamp tube ,( the one closer to guitar input jack) if no hum , the tube is noisy or problem in this tube circuit. If hum is still there, this tube or is circuit is not your hum problem. Do that with all preamp tubes.

If hum is there with all preamp tube remove , this could be a bad output tube and/wrong bias .

Is your 3 prong power wire are ok and wall outlet grounded ?

 

[scottcrud]

Not necessarily, my lead channel had no hum, but my clean channel was noisy as hell, brand new tubes, swapped out for brand new tubes as well as NOS tubes that DO not hum on my other .50Cal+...My Caps were all bloated and turning color.
Is his problem caps? Who knows until he takes it to a good amp tech.
All I said was that it could be caps.