Gibson GA40RVT

[Jack Dotson]

Hello all. Just found this forum while trying to find some info on my new amp.

I just bought this yesterday from Sweetwater without ever having heard it. On paper it just looked too good to pass up. Anyhow, it does sound great except for one thing. When holding some single notes, especially an E, I get a high pitch fizzing sound as the signal sustains. It's faint, but I can easily reproduce it every time.

Kind of sounds like a little bit of tube rattle? Anyhow, it's annoying and I was curious to see if anyone else owns one of these and has a similar issue.

The amp sounds really great, but I'm not sure I'm going to be able to live with this issue as I only play at home and now that I know it's there I've started to listen for it.

Also, does anyone have the tube chart for these. I tried rolling in some of my Tung-Sol pre-amp tube, but believe it or not, I actually preferred the sound of the stock Solvtech's in this amp. And the fizzing issue was also present with the Tung-Sol's. Power tubes maybe?

Thanks.

[tubeswell]

Try replacing the output tubes with new ones and see if the problem persists. You are going to need new output tubes eventually anyway, so might as well splash out for them now. JM2CW

[Jack Dotson]

Try replacing the output tubes with new ones and see if the problem persists. You are going to need new output tubes eventually anyway, so might as well splash out for them now. JM2CW

I've got a couple of spare Mesa Boogie 6L6's. I'll roll them out today. Thanks for the suggestion.

BTW, do all of you have to pull the back off the amp to change tubes?

[tubeswell]

do all of you have to pull the back off the amp to change tubes?

You have to get at the tubes somehow

[Jack Dotson]

You have to get at the tubes somehow

I realize this, but I thought maybe someone had tried replacing them through the top vent, but after looking a little closer I see there's just not enough room.

BTW, I rolled in my other set of power tubes today and it cleared the issue.

Thanks for the suggestion.

It's a pity that we have to change tubes in a brand new amp.

[tubeswell]

Oh I missed the bit about new amp - sorry - I suggest that you put the dud tubes back in, take it back to the store and demand warranty satisfaction! (Hopefully you are likely to get a new set of replacement tubes)