Spike in B+

[EETStudent]

Im working on old Univox chassis that I converted to a 5F11. I just changed out the electrolytics in the power supply with Sprauge Atoms. With the old caps(1x20uF Mallory, and 2x10uF original Elons), the B+ was running about 305V with a pair of 6AQ5s. After the swap, the B+ is around 420V with 3x16uF!! I know the caps were a little old, but there is no way the original design called for such voltage with a pair of 6AQ5. I changed out the resistor string and the cathode resistor, but all with equal value replacements. My tubes are sure to burn up soon! Why the spike?

[Steve Conner]

I'd guess you broke something while you were in there, causing the power tubes to stop drawing current. Or, you're measuring it with the tubes removed.

[Jazz P Bass]

Measure the Vac windings & take it from there.