RH300G3/R412CXM Hum?

Has anyone experienced a low HUM after turning on the amp?

Not a buzz, just a Hum. The hum is present whether the master volume is turned all the way down or all the way up and never changes in volume.

This is also with no guitar or guitar chord plugged in.

I assumed this solid state amp would be pretty quiet.

Curious before sending it in for repair... Thanks.

I have the same problem as you, but i'm also having a problem with too much bass, even when it's turned all down

Thanks for the post reply.

I took the amp and cabinet in for warranty repair this past Friday.

The guy there plugged the entire amp/cab in and fired it up. He agreed that there was excessive hum but not sure exactly where it would be coming from by simply listening.

He also ran the cabinet thru a series of tests on the spot which apparantly checked out ok. He said it would be a few days before he can diagnose the amp but he let us take the cabinet back home right away.

I will post another reply after they diagnose/repair the head. I hope they can actually repair it...

The only thing we're experiencing regarding the bass issue you mention is if it's up too high (even at 5), it really rings thru (kind of a volume swell) after you hit a chord or note. But, we were able to back it off enough to stop it.

I hope others chime in if they are experiencing this and hopefully benefit/share their experiences...

I have the same problem as you,but i have rh150g3.hum, when is all knobs turns down...and guitar unplugged...
anyone help?

Hey All,

Though you may not like this reply...

My patience wore too thin after a month and a half of waiting for repair on the RH300G3.

Paraphrasing as much as possible as I made way many phone calls prior to any resolution... US Music (owner of Randall) doesn't appear to have too great of a tech support staff with regards to helping their remote repair shops. US Music recommended the shop I took mine to as "the best in Michigan". This repair shop (Art's Audio) had trouble talking to anyone each time they called US Music. They couldn't get the proper schematic for the amp. It also appears they've made modifications to the original design as once they did receive the proper one, it didn't include the mod's so it was still too difficult for the repair shop to trace the problem. US Music recommended they send it to them for another 3 to 6 weeks to repair.

Art's Audio asked me to be patient but I felt it was taking too long. Luckily, I called the store I purchased it from and they worked with me to replace the amp with one from their store and they will take the one in for repair back once rectified.

I went and played thru the "in store replacement" before taking it home and it doesn't have the hum problem.

Sounds hit or miss to me. I got lucky, eventually. Not sure everyone else will enjoy the same outcome. I will keep the amp but not recommend it to anyone else. I will recommend Motor City Guitar in White Lake, MI to anyone withing driving range for anything guitar related!

PS - Yes, the bass issue can rear it's ugly head but somehow on this amp, with it turned most of the way down, it's manageable. Good luck to all in this mess. I hope much is learned for those already owning as well as considering purchasing.