Road King II sounding flabby - Possible Causes??

[ianvomsaal]

I bought a Road King II (NEW) just over a year ago (Jan 2013).
Over the last 6 months I started noticing that my low end has really started sounding flabby and farty if I turn up over like 10'o'clock (I didn't notice this when I first got the amp) - What I mean by flabby is, it almost sounds like something's clipping; I had a Fender 4x10 Hot Rod Deville that sort of sounded like this because one of the tube sockets got so hot that it un-soldered itself, thus the amp was only running on one(1) 6L6 instead of two(2) and couldn't handle it; I had it re-soldered.

I'm running my RK2 with all tubes on (120-watts) through an oversized Port City 2x12 Cab with Vintage 30's (8-ohms, also 120-watts), so everything matches up fine - However it almost sounds like the speakers are farting, like the speakers can't handle the output on what would only be a volume of 3 on a number scale (instead of 10'o'clock on a clock face) - However, I've run many amps with Vintage 30's much louder than this without the speaker sounding like this, so I'm thinking it might be a tube issue - Thoughts??? Sadly I don't have the $$ to replace all the tubes right now, so I'm just looking for a few thoughts as to what others think might be causing the flabby farting low end??????

Thanks in advance for any thoughts or ideas - Cheers . . . Ian

 

[firmani99]

Ive noticed that my 3 channel dual rec started doing the same thing. New power tubes didn't fix it so im at a loss. I am going to take it apart and see if i can find anything visibly wrong. Did you ever solve yours?

Another thing that is odd is that it sounds fairly good with a 16 ohm cab. Terrible with an 8 ohm. And horrendous with a four ohm. same problem that you described but it gets worse and worse depending on the ohm rating of the cab. And it was always plugged into the proper respective output on the amp. Even with a marshall cab at 16 ohm vs the same cab run at 4 ohm. sounds decent one way and terrible the other.

Could it possibly be the transformer?

 

[ianvomsaal]

NO I still haven't figured it out yet - What I did do that helped a little was bring my watts down from 120 to 100 (by switching to just the four 6L6's instead of the two EL34s combined with four 6L6's); That seemed to help a little, but it's still NOT as good as when I first got the amp - The next thing I'm going to do is replace the V-1 tube with a SPAX7 (since the V-1 is the tube that gets the brunt of the blow, thus compounds through all the other tubes); a good friend/recording engineer agreed that I should replace V-1 tube first, then try the other 12AX7's since the pre-amp is usually the first stop with issues - The next step is to scroll down in my phone to M and give Mesa a call - I don't really think it would be an ohm issue, especially since Mesa on makes 4ohm & 8ohm cabs for both the Road King and Rectifier amps - I surely hope that there's not a transformer issue (input or output) as my amp is only a year old - Please let me know if you figure anything out after you take it apart - Cheers . . . Ian

 

[firmani99]

I definitely will.