Thin Sound on all Channels

[FrankS]

My Mark V combo sounded horrible at my last band practice. It sounded thin and weak with little or no bass. I have since swapped the 6L6's out for a new set of EL34's that I keep as a spare set of tubes. It sounds better but maybe still a little thin. When I checked to make sure I had switched the bias switch to EL34 and to make sure the speaker cable hadn't been unplugged by mistake that the send level knob on the effects loop was turned all the way down. I must have have turned it down by mistake while reaching behind the amp to adjust a reverb knob. Has anyone else had the same thing happen?

Also, is a thin, weak sound possibly a symptom of a bad speaker?

 

[Adambomb]

Im not understanding.. So you put effects loop back to noon and everything is all better right?

 

[Scary]

Keep the FX send level around 11 and up otherwise you'll lose your tone. You have to keep the signal hot all the way through the line.

 

[Vavoom]

My Mark V combo sounded horrible at my last band practice. It sounded thin and weak with little or no bass. I have since swapped the 6L6's out for a new set of EL34's that I keep as a spare set of tubes. It sounds better but maybe still a little thin. When I checked to make sure I had switched the bias switch to EL34 and to make sure the speaker cable hadn't been unplugged by mistake that the send level knob on the effects loop was turned all the way down. I must have have turned it down by mistake while reaching behind the amp to adjust a reverb knob. Has anyone else had the same thing happen?

Also, is a thin, weak sound possibly a symptom of a bad speaker?

I had the same thing happen last gig I played. It was a patch cable. (that I made) Thin and volume was drastically reduced. Maybe a patch cable?