In this video we'll test out the tone and take a look at the guts of a 1965 Gregory Mark V amplifier. This is a series filament (widowmaker) type amp which I have just serviced with a new 3-prong cord, fuse, new caps, and a new tremolo pot. The amp also got a good cleaning while on the bench. Very nice tone - clear and punchy with good rock and roll overdrive when pushed hard. Speaker is a Quam 8" AlNiCo and is original. Tubes are 12AU6, 12AV6, 50C5, and a 35W4.
Here's a link to the schematic: http://2.bp.blogspot.com/_iQOTeAgvE8o/Sfis45jsCRI/AAAAAAAAAiE/hDEu_KarRs8/s1600/Gregory_Mark_V_Gemini_700.jpg
Based in New Jersey, with a sales office in NYC, Gregory are one of the oft forgotten makers of vintage guitars amps. Their literature claimed they were the first company to develop the tremolo circuit for use in guitar amps. They apparently made amps from the early 1940s thru the late 60s, possibly into the 70s. Their later amps are often British influenced circuits, incorporating EL-84 tubes into many of their designs. This design is a standard series filament amp design, a version of which was used by countless companies of the 50s and 60s, including Lectrolab in their Harmony H400 and Danelectro in their Cadet and Silvertone 1430. These companies were churning out small practice amps by the thousands for sale through various department store catalogs and wholesalers. Gregory amps were sold through Grossman wholesale catalogs, and they were known to make amps for other brands such as Stewart.