The VAC Renaissance amps are quite finnicky when it comes to 300-B's for a couple of different reasons.
First, any 300-B put in the amp must be made to the standard Western Electric 300-B specification. "Super" 300-B's that run higher plate voltages, such as the KR Audio 300BXLS, will burn up the amp.
Second, the VAC Ren's run 300B's hard -- 95% of the WeCo spec maximum voltage. This means that tubes like the vast majority of meshplates cannot be run in the Renaissance amps for the opposite reason - they can't handle the voltage.
I've owned VAC Renaissance amps for nine years and they require carefully vetted output tubes. Sophia Electric used to market a special set of the Sophia tubes for VAC Renaissance amps, which were the basic Sophia tube, but carefully tested at plate voltages that resemble the voltage that 300B's see in the Renaissance circuit. Generally, as for transconductance, 300B's for the Renaissance amps should test in the 3,000-5,000 range. In addition, the plate-to-cathode voltage for 300B's in the Renaissance amps is approximately 430 volts dc, with idle current approximately 85 to 90 milliamperes in a self-bias (cathode bias) circuit. Again, this is approximately 5% below the maximum rating for the WeCo spec 300B. The milliamp and transconductance testing for purposes of matching must be done at these voltage levels, or you will find out the hard way that your 300B's didn't make the cut.
Call Kevin Hayes at VAC and ask him whether this tube is a "super tube". From looking at the Emission Labs site, it is not entirely clear, but it is clear that it is not a standard WeCo spec 300B.
The Sophia Electric, Full Music and E.A.T. 300B's are premium tubes to run with the Renaissance amps, but they have to be carefully tested at the plate voltages they will see in the Renaisaance amps in order to ensure that they can handle the circuit.
