Great compromise between tone and reliability. Nice mids, sparkling highs and solid bottom end. They can take the heat and vibration in stride without any negative tonal effects. Ruby's matching process is very exact and our tubes are matched within +/- 1 mA (mille amp) of each other.
A premium tube that produces more power, more tone, and higher fidelity with an extended dynamic range. All Ruby output tubes are labeled on the base with the exact matching measurements for plate current and transconductance. By matching these parameters, optimal performance and long life are ensured.