Audio Research VS 55 power amp - tube question

Just received this amp, tubes are not labeled.
Could I just place the 6550EH randomly into each sockets?
V7 V5 V4 V6 are labeled on the plate where the tubes are inserted but none of my tubes have any labeling.


If the tubes are not marked on the bases you have little choice. Do you have a multi meter? After the amps have warmed up for about 15 minutes. I would test the bias of the power tubes. See how close the secondary tubes are to 65ma and if necessary move the tubes around.

I assume that you bought the amp used so you do not know how many hours are really on the power tubes. If it were me I would buy a new set of power tubes and keep the old ones as spares. You want to get either two matched pairs or a matched quad. I would also see if you could find a place to have the old tubes tested.