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.

R
rapogee

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.