Ruby Tube's most popular and highest quality 12AX7A tube.
All Ruby Preamp Tubes are tested by Magic Parts™ for quality assurance and selected for low microphonics and hum. This ensures that even the highest gain tubes will be quiet and dependable. Ruby Tubes come with a 6-month manufacturer's warranty.
The 12AX7AC5 is known for clear highs and mids with a slightly subdued low end that make some amps feel tighter. A great tube for high gain amps or lower gain amps that are looking for a little more "bite".
HG is great in any stage of low and mid gain amps, and all but the first stage of high gain amps. HG+ has extremely low microphonics and intended for use in the first stage of high gain amps.