Choosing the right tube

What brand of tubes are the worst? This shows defective tubes that where pulled out of tube amps over the course of one year. They are mostly out of guitar amps.

6L6 Power Tube Types

Brand Qty Percent
Ruby 6L6GCM-STR 13 48%
Groove Tubes GT-6L6B 7 26%
Mesa-Boogie 6L6GC 3 11%
Electro-Harmonix 6L6 EH 2 7%
Sovtek 5881/6L6WGC 2 7%

We found that the Groove Tubes were mostly out of Fender amps and the tubes themselves had many more years than the other brands. These were typically the tubes that the guitarist had in their amp since they bought it. The Groove Tubes GT6L6B are Sovtek 5881WXT.

EL34 Power Tube Types

Brand Qty Percent
Winged C EL34 6 55%
Ruby EL34B-STR 3 27%
Groove Tubes GT-EL34-M 2 18%

The Winged C tubes were all labeled Marshall and were the original tubes that came with the Marshall amps.

6550 Power Tube Types

Brand Qty Percent
Ruby 6550ASTR 2 40%
Sovtek 6550WE 2 40%
GE 6550 1 20%

These are mostly from Ampeg SVT bass amps. Winged C 6550 tubs were a very popular choice for replacement tubes. Note that there aren’t any defective Winged C tubes in the list. Electro-Harmonix was also a popular choice.

Sovtek, Groove Tubes, Fender, or Mesa-Boogie?

Notice the white debris, that’s from the plate. It’s time to change your tubes when you see this.