Need Tubes? Afraid Guitar Amp Will Explode? Easy Chart!

...your guitar amplifier:

Then:

Has tubes with a rating

Replace them with a matched set of tubes of the same rating or an equivalent from the Tube Rating Conversion Chart

Has no way to adjust the bias

Replace them with a matched set of tubes rated Sovtek Medium or an equivalent.

Unrated Tubes and bias test points

Replace them with a matched set of tubes rated Sovtek Medium or an equivalent. Set the bias according to the directions on the Schematic or in the owner’s manual.

Unrated Tubes, a bias adjust, and you have a bias probe

Replace them with a matched set of tubes rated Sovtek Medium or an equivalent. Set the bias to the suggested figure on the Schematic or in the owner’s manual.

Is rated 40-50 watts

Buy a matched pair.

Is rated 85-100 watts

Buy a matched quad. Don’t settle for 2 matched pairs unless your amp has a balance adjust. Even then a matched quad (all 4 the same) is much better!