.50 cal + hum

[rvschulz]

okay, here is the story - went to a new band practice last night and put the combo in the truck. did not really give enough oomph to get it high enough to put behind the seat and "bumped" it on the door frame a little.

go to practice, no more issues until i get the guitar out and i forgot my main guitar so i am playing my backup - a hwy1 strat. when we play, the other guitar is pretty loud through a twin reverb so i turn it up a little. can i blow him away, of course, but that's not the issue.

during some pauses, i hum. some pauses i don't really, but it's mostly there. some pauses he hums. i haven't tried the amp again since practice ended late. i will try again tonight. i usually play a humbucker guitar. however, the strat sounded sweet and really was a complimentary sound to the distortion shred thing the other player was doing.

where do i begin to track this down - cable ? noise suppressor ? amp ? if you have experienced this, please let me know. thanks in advance.

 

[Schmoog]

could be a messed up ground in the strat, could be dirty power at your practice spot. try it first with a guitar you know doesnt hum, and in a room with clean power

 

[Boogiebabies]

The lights and wall voltage may be causing the hum. If you do not have it at home, you may need a power conditioner.

 

[stomper]

Hi, my first post here, and I think I can help. The 50 cal. + has a Sus 4 mounting system which makes the chassis float on rubber cushions. This requires the shielding under the top of the cabinet to make contact with the chassis via two copper spring units on the underside of the cabinet. If you are skilled in electronic repair and understand the dangers of such work, proceed as directed. If not, seek someone who is. Tube amps contain lethal voltages inside which CAN kill you if you touch the wrong things. Still with me? Remove the chassis from the cab and inspect the two copper springs. They were likely crushed, or moved when you bumped the amp. Unscrew each copper spring and readjust the "fingers" so that they will make contact with the chassis again when you install it back into the cab. This should do it. If you want to go another step, install a wire that connects the chassis to one of the copper springs. Now, no matter what bumps your amp recieves, it will always be shielded. I made the wire on my amp in two parts with a screw nut holding each part together. It makes servicing much easier. FWIW, I had the same problem this week and did this mod. I just finished a recording session tonight with the amp and it performed flawlessly. Good luck with your amp. 8)

 

[rvschulz]

to remove the chassis ... some screws perhaps which attach the chassis to the cabinet ?? by the way, amp unplugged - i can still get electrocuted ? not to sound like a wise ***, i generally unplug electrical equipment when dealing with touching unshielded wiring.

thanks for the info and i will explore this later this evening.

 

[scottcrud]

Even with your amp unplugged, you can get shocked if you touch a filter cap in the right spot, cause they hold a charge for a long time.

 

[stomper]

The 50 cal. boogies use about 429 volts of dc on the plates of the tubes. The capacitors can hold this charge even with the amp off. Fortunately, your problem is likely mechanical and not electrical. So, you won't have to touch anything inside the chassis.

Unplug the amp and then turn it on and take it off standby while it is unplugged. This will drain the filter caps of their charge. Let the amp sit a few minutes before you do anything else. Do this with the amp cold too. Getting burned by hot tubes is no picnic either. The 4 screws on the top of the amp will let the chassis slide out. Unplug the speaker and place the chassis in a safe spot so the tubes don't have pressure on them. Proceed as I descibed before. Let us know how you make out.