Very clean mid-'60s Guild Thunderbird amp on eBay. The version 1 with the kitchen dinette side banding and stick-'em-on faux wood-grain paper on the sides (I know, I know ... you're thinking: "What were they thinking?" :? ) This was the 'big-boy' of the Guild amp line immediately following the Guild-Peg era; twin 7591s, fixed-bias, tremolo and reverb; 1X12" and 1X8" CTS speakers stock.
Different copy of the same model:
Two-channel but not foot-switchable; trem on one channel only but reverb on both. Bright switches plus treble and bass in both channels. The Thunderbird, like it's little bro the T1 RVT, also uses speaker-coupled reverb where the yellow is the feed from the 12" speaker directly to the reverb can through a series capacitor/resistor but no transformer or capacitor-coupling like Ampeg. In the T1 RVT when the reverb was off, the reverb amp (shown in the dotted green box below) amplified the dry signal. When the reverb was on, the wet signal amplified through the 8" speaker. In the Thunderbird, the 8" reverb speaker only 'on' when the reverb was on ... didn't handle the dry signal.
The amps are prized by several LTG members however the cabinets are particle board; extreme care needed in shipping.
Different copy of the same model:
Two-channel but not foot-switchable; trem on one channel only but reverb on both. Bright switches plus treble and bass in both channels. The Thunderbird, like it's little bro the T1 RVT, also uses speaker-coupled reverb where the yellow is the feed from the 12" speaker directly to the reverb can through a series capacitor/resistor but no transformer or capacitor-coupling like Ampeg. In the T1 RVT when the reverb was off, the reverb amp (shown in the dotted green box below) amplified the dry signal. When the reverb was on, the wet signal amplified through the 8" speaker. In the Thunderbird, the 8" reverb speaker only 'on' when the reverb was on ... didn't handle the dry signal.
The amps are prized by several LTG members however the cabinets are particle board; extreme care needed in shipping.