Bernard d'Uur's little lab; the docter is in!

 I love old amps! And this amp is pretty old!      Gibson, you know, that brand that produces a lot of great guitars and basses, also produced amps. In the 1940's they produced beautiful amps to suit their guitars. And as it was the 40's, amp designs were still pretty basic and new.  In 1947 the GA-25 was introduced; a single channel dual knobbed amp that uses two different speakers and has two 6V6 output tubes to give the player a staggering 12W of output power. In 1948 this amp was replaced by the GA-30: dual channel, three knobbed amp that used the same topology of the GA-25 but just added a couple of Watts extra out of the two 6V6 tubes. This amp also introduced the 'Tone Expander' switch, a switch in the negative feedback loop to regain your lows. This GA-30 was a winner and sold so well that it was reissued in a number of versions or was used as a bare essential in the design of other amps.      This 1950 Gibson GA-30 came in for some TLC bu...