Advice Regarding Mark V Problem

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?

Power tubes

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.

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.

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

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.

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)