Advice Regarding Mark V Problem

[RMosack]

In the last two days, I’ve noticed something off about my Mark V. Yesterday, I heard a harsh ghost note on the G string mostly of my Tele. Made me switch to the Les Paul. But it seemed weird. That Tele sounds fine through other amps.

Today, I grabbed a Strat and it was worse. My guitar just sounded oddly harsh and awful. Thought I was losing my marbles. Then I realized, it’s not my guitars all of a sudden going south. It’s the amp.

I realized that I’d ever changed a single tube in this amp. In fact, I haven’t changed a tube in any amp in years - flip them all too soon. Any ideas on where I should look first? Harsh, thin, grating sound on all channels, all modes. V1?

 

[Markedman]

Power tubes

 

[RMosack]

Thanks. Oddly enough, it happens in all three power modes. So it looks like I’m replacing all four tubes.

It’s especially prevalent on a C on the G string and the G above it up on the B string. You can really hear it in that range. Like a weird, sharp secondary edge. Like it’s farting out in a harsh way.

 

[RMosack]

Definitely a bad V8. I have two matched pairs of Groove Tubes 6L6 in the house. Debating whether I should change just the inner pair (V8 and V9), or all four.

 

[mace]

Should be ok just replacing the pair. Do you have a recording of that sound of the amp sounding funky with the G string?

 

[RMosack]

The V8 was dead. I replaced the inner pair (V8 and V9) and it’s back to normal.

The sound with the bad tube was like a slightly reduced volume with a harsh, gated attack. Almost like when you ping on a high fret. I’m actually surprised it worked as well as it did with a bad V8.

 

[Jeronimo]

Happy that you resolved the issue quickly! Same thing happened to me after I bought a used mkV. Replacing the inner pair solved the issue, my amp came with 2 matched pairs of Mesa 6L6 tubes, but the 2 pairs were different from eachother. I replaced the pair by the type that was the standard at the time (and matching the outer pair)