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1966 Gibson GA-45RVT

Year: 1966
Brand: Gibson
Model: GA-45RVT
Class: Tube
Owner: Jeff Hewitt
Status: in the process of being repaired.

Output Power: 25w Inputs: 2 per Ch
Channels: 2
Controls: volume, Bass, treble
Features: Reverb, Tremolo, Presence Switch
Tubes: OA2, 4x6EU7, 1x12AU7, 1x6CG7, 2x6L6
Speaker: 2- 10''

2016-01-30: All new capacitors were installed, while this cleaned up channel 1 there was still a lot of feedback and interference from channel 2. After going over the schematic it the twin t filter on the second channel has been bypassed and wired straight with no resistor. This can create a lot of gain and in this case feedback so I installed a 1m resistor to control the gain. Channel 1 still goes through it's twin t filter, and I dig the sound on that channel so it will be staying stock. The reverb still causes a lot of feed back, after a bit of modification I was able to clean it up and find the main cause of the feed back, an incorrect reverb pan. While it's the wrong pan it gets super lush. I was able to use a resistor on the reverb input line on the amp to gate the controls from feedback. The original speakers were missing, so a new pair of Celestion 10s were installed and wired in series. A new set of Sovtek 6l6 power tubes were installed. The original tremolo opticoupler assembly had died and want not repairable. With a bit of work and testing I was able to build a new unit using a good sized LDR and a neon bulb. The new unit is serviceable not sealed like the original.