@hilde45 More tubes are used for the power supply in my preamps, being both tube rectified and tube regulated- the two 12A_7 tubes do the stage amplification and buffer job. A tube rectifier is smoother than diodes as there's no diode switching occurring, and instead of using an IC-based "chip" regulator, I use gas-charged neon tubes which were used in lab equipment before solid state was invented. The 5U4GB rectifier will last a good long time (up to 5 years for the NOS tubes) as they're only being used at about 5% of their capacity. The same goes for the regulators, but regulators are a cheaper tube, so they may fail after a couple of years respectively. All of this helps provide a very organic and smooth sounding power supply, and in tube-based gear, all of this is audible as the signal rides on the high voltage supply. Typically good NOS rectifiers run $10-$15 and the OD3 regulators are about the same per pair. Best regards, Aric
