No prob. You'll have to figure out which tubes are for the low gain. Generally in those pre sections there is a pair of 12AX7 for low ouput like phono and a pair for high output. Then you might have another single tube as a final output stage, sometimes combined with a rectifier. The larger tubes will be for output power for the amp section. Plug into the phono input and remove one pair, if it plays those are your low output, if it doesn't play anything you've removed them.