| Year: | before '73 |
| Model: | GRO50 |
| Model Number: | GRO50 |
| Serial Number: | 151 |
| Config: | Head |
| Control Panel: | Plexi panel |
| Control Panel Layout: | Input - F.A.C. - Bass - Treble - H.F.Boost - Gain - Reverb Send - Reverb Return - Pilot Light - Power |
| Rear Panel Layout: | Mains chord - Voltage selector - 2 fuse holders - Slave output - Impedance selector - 2 speakers outs |
| Cabinet: | size? |
| Weight: | |
| Speakers/Load: | 3.75/7.5/15 Ohm or 100V line |
| Speaker model: | N/A |
| Effects: | N/A |
| Output: | 50 Watts |
| Preamp tubes: | 1.5 x 12AX7 ??? |
| Power tubes: | 2 x EL34 |
| Bias: | Fixed bias |
| Rectifier: | solid state |
| Phase Inverter: | Cathodyne type: 1/2 x 12ax7 |
| Circuit: | '72 type schematic??? |
| Chassis layout: | preamp tubes are chassis mounted! |
| Comments: | This amp has older impedance values. Preamp tubes arechassis mounted. |