Tube Amplifier Buzz! Please help!!

[wilde_jono]

Hi all, sorry if this isn't posted correctly, it's my first time posting.

I'm using an OR15H tube amp head, just a 15 watt amp. It's buzzing like crazy even when the volume's of the amp/guitar are turned down. Using a clean sound, the buzz is noticeable and get's a lot worse as the pre-amp is turned up. I think it's either the tube's in the amplifier (which are about a year old) or the speaker cable from head to cab.
I'm not running any pedals in the line, just a guitar to amp.

Does anyone have any advice as to how to find the cause of the buzz? It'd be appreciated.

- Jonathan

 

[FuseG4]

Re: Tube Amplifier Buzz! Please help!!

tubes are a common cause but it could be other things.
I used to be a DIY guy but found out that a good amp repair guy is a faster, easier way to get it done. He can tell you which tube is failing (if that's what it is) and replace it with a good, known-to-be-working tube, or work on whatever it is, and that for me beats waiting for tubes to get shipped to me via mail. Could be a bad filter cap which is not easily user-serviceable and he'd be able to find out and fix it.

If you wanna try everything you can first, get a 12ax7 you know is working and try it in each preamp slot until the problem goes away. Visually inspect the power tubes. They have big plates in them, and look and see if any of those are glowing red or orange (like the coils on an electric stove). Normally they should just have the filament on the inside of the plates glowing (like a lightbulb). If any of the power tubes are glowing on the plates, shut the amp off and replace your power tubes.
Most of the time it's tubes causing issues but I had a Deluxe Reverb that hummed bad no matter what I did and it turned out to be a filter cap (which one should NOT attempt to replace unless you know what you're doing. Potentially lethal voltages etc).

I also have an OR15, great amp. Hope you get yours running again soon.

 

[Chickenwings]

Re: Tube Amplifier Buzz! Please help!!

Always start with a tube swap before looking for other less likely culprits.

 

[jackson111]

Re: Tube Amplifier Buzz! Please help!!

have you used the amp in your house / apartment before. the reason i am asking is i had a really loud buzz on all my amps and just figured it was something i had to live with. then i found out my house has a poor ground, so i ran a bare #8 from my copper water pipe main to the receptacle ground post and now everything is nice and quite no more buzz. if the tube swap doesnt work check your ground. also if your voltage is to low it can cause a buzz. you can also try to take it to a friends house and try it to see if it gets better, if it does it aint the amp