4S Universal Preamplifier for 12A*7 Tubes
The basis for this tube preamplifier started out as a post in the Super simple single stage tube preamp thread on the website Forum. One of the members (see Mark’s 4S Universal Valve Preamps) had suggested building a Super Simple Single Stage Preamp (“4S” Preamp for short) and there was much discussion concerning various tubes, […]
4S Universal Preamplifier for 12A*7 Tubes Continue Reading