12au7 preamp

In this build I employed a single stage tube preamp to provide gain and volume control to my 3W 6AS7 SET amp. This preamp uses a 24VAC wall wart and by configuring a 24/240V step down tranni to work backwards I can gain 280VDC across the 12AU7. No hook-up wire is used in the amp cct. only component-2-component wiring. The preamp produces no hum or buzz. It extends to a deep rich bass and very natural mids and highs. The frequency response is flat from 10hz to 130KHz and square way performance is exceptional. There is more information in the Super simple single stage tube preamp thread on the forum.

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