Because each KT150 consumes 2.0A of filament current (more than the KT88 and 6550), we recommend contacting your equipment manufacturer to ensure your power supply is capable of powering this tube.
Conclusion
While brighter sounding systems may expose the EL34’s as being a little too spicy in the upper mid and treble, they are articulate, open and expressive and given the modest power rating, they sound surprisingly powerful. With these tubes, the PrimaLuna amp is capable of injecting life and excitement into just about any speaker.
KT150’s are super-powerful tubes that really have incredible tube-untypical bass. Full-bodied and powerful but also articulate and well-controlled they build a foundation onto which a sonorous and timbrally full midrange remains powerful yet wholly neutral and natural. The treble is perfectly integrated and is not dull nor does it stand out. It is open and articulate but absolutely never bright or forward. Although neither the Wilsons nor the Franco Serblin Accordo’s are particularly power-hungry, I feel that both speakers perform better with the KT150’s than with the EL34’s. Although their extra power is certainly a benefit, it is their solidity and natural timbre that has really won me over.