Original tube type for Philly 7a preamp?

Hello, I inherited a Philly Audio 7a (I believe) and all it had with it was a 6x4 rectifier tube..What went in the other three slots? 12ax7 between two 6922 or 6DJ8..or? I'd like to gut the components and replace all caps, wiring, input selector and toss the pot for a stepped attenuator..etc Anyone have any info on these? info is scare next to none...
Thanks and happy listening!