Lamp and transistors.
gain + drive lamp, 48v power supply, phase reverse, 80Hz filter, attenuator.
6.35 + XLR jack.
half-rack format

UTILIZATION

Simple and direct not need manual (English).

SOUND QUALITY

Its transparent and clear (except when the lamp has done its job, saturation guaranteed)

OVERALL OPINION

3 weeks of use and always satisfied.
quality and interesting prices
What a difference with my old preamp art!