Mark Baier of Victoria Amps told me that these were safe to use as a low-output alternative in my Victoria Regal guitar amp. They sound great at low levels and offer a lot of compression prior to distorting, which makes them fun to use in a practice amp. Their distortion characteristics are somewhere between and el84 and a 6V6, but with more compression. I would imagine a push-pull amplifier designed around these would be great for recording or playing at home.