I replaced the power section of my Ashdown CTM30 with these. Love the tone it gave the bass – very full midrange, clear attacking highs, and more than enough clean low end for my needs.
They've lasted for a seriously long time – I'm talking years on end. I've been using tube amps for bass for about 10yrs, and this is the first time I've had no reliability concerns, which might be a combination of the amp, the tubes, how I treat my amps nowadays... Whatever it is, I'm really happy with these tubes and will buy again in a heartbeat when they finally stop performing.