Reissue of the famous Mullard CV4004, it is a tube of the 12AX7 family, which can be used as a replacement for any tube electronics, be it HiFi or instrument. This is a high gain, short plate tube to reduce miking, making it ideal for use in high gain combo amps. The sound is similar to that of the 12AX7 Mullard reissue with a long, linear plate and with excellent detail, having a little less gain, but the noise rate is as we say much lower. Selected for minimum noise and microphones.