James, searching at eBay for "RCA shorting plugs" (without the quotes) will lead you to a number of sellers offering them at low cost.
Good point by Ralph (Atmasphere) re the possibility that the amp doesn't provide grid stopper resistors in its design. If that proves to be the case, James, I would think that if you explained the situation to Vladimir he could have them installed at modest cost. It would just involve the addition of a physically small low power resistor in series with the grid of each tube.
Good luck. Best regards,
-- Al
Good point by Ralph (Atmasphere) re the possibility that the amp doesn't provide grid stopper resistors in its design. If that proves to be the case, James, I would think that if you explained the situation to Vladimir he could have them installed at modest cost. It would just involve the addition of a physically small low power resistor in series with the grid of each tube.
Good luck. Best regards,
-- Al