Quick cap drain on Hoffman Princeton Reverb build

[mopar39]

I have just finished the chassis build on a Hoffman Princeton Reverb build.  After a thorough pre fire-up inspection, I hooked it up to my variac and brought up voltage. All OK.  It sounds awesome with no hum, buzz or noise.  My question is related to shut down. The Cap voltages drop to a few volts within 10-15 seconds.  I thought that they should persist for longer time.  I did search the board for information but didn't find any similar. Any suggestions? 

[sluckey]

Very normal. As long as the tubes are still hot, they will continue to draw current which puts a load on the power supply caps and drains them. Some amps drain the caps more quickly than others.

[PRR]

The working bias condition is similar to a 7,000Ω resistor; you may have 20uFd+20uFd of main capacitor (before large B+ resistors). 7000Ω against 40uFd is a 0.28 second time constant. The voltage will lose 63% in that time, 37%. (Of 420V: 155V.) I do not know what "few" is, but it should be 5V in around 1 second. (Many meters don't drop that fast.)

The real problem is in a fault, tubes NOT sucking current. Then the charge tries to last "forever". (In most tube amps there is no path out of B+ except through tubes.) This can shock the technician.