I’ve been trying/using an Audio Research Reference 150SE stereo amplifier that uses eight (four per channel) of the (relatively new designed) KT-150 power tubes (150W pc) and the input tubes are four 6H30s. The tubes are new and matched from Audio Research. It has tubes (two 6550s) in the power supply regulation. Power supply energy storage: 1040 joules for two channels.
The SL A3PX speakers sound excellent when driven by it.
Surprisingly or not, it is not “better” (whatever that means) than the two Audio Research VT-150SE mono amplifiers I’ve been using for the past twenty-five years on SoundLab speakers.
The VT-150SEs also are rated at 150W pc but uses eight (four per channel/amplifier) of the 6550 power tubes and four (two per amplifier) 6922 input tubes. It also use tubes (two 6550s) in the power supply regulation. Power supply energy storage: 420 joules for each channel/amplifier.
When comparing the VT-150SEs on SoundLab A3PX ELS, the Reference 150SE tonal balance is slightly leaner (taut) upper bass and slightly more forward upper mid-range, using the 8 ohm taps on the amplifiers. Speakers are set flat (0) with treble at 1-2 o’clock.
It has only been a few days of comparison listening and switching so I’ll continue…
