Very dumb mistake

[Bruce / Mission Amps]

I've refurbed a few of these over the years....cool amp.

10K... hmm which filter cap was it on?
That is more resistance the the output transformer has in impedance on these amps... so I suspect you just loaded down the PT more then normal but not enough to damage anything except the actual power tube or one of the SS diode rectifiers.
Does it still blow the fuse with the power tube out and everything hooked back up? If yes... I'd replace the two rectifier diodes now.

[Bob Opera]

I will try that tonight Bruce. I did test the two rectifier diodes with the diode testing function on my multimeter and got 0.55V drop on both one way and open the other way. Is this meaningful at all or about as meaningless as testing an electrolytic w/ a multimeter?

[Bob Opera]

Well, I rewired all the connections that I took apart and it is not blowing fuses with or without the power tube and the hum is gone. There is some weirdness with the pilot light.. it sometimes won't turn on unless i fiddle around with the leads of the LED. Easy fix. I'll give it a thorough cleaning and retensioning as suggested by Chuck. At this point I have no explanation for the popped fuses other than the aforementioned oxidation and gunk gremlins.

oh.. one thing that I left out is that the only speaker i had available while waiting for the replacement pair of 8"s to arrive is a 16 ohm. The OT wants to see 4 ohms.. while this may have been hard on it, it couldn't have caused the fuses to pop, could it?

PS: Bruce, the tolex on the amp cabinet in your avatar is very reminiscent of this Twin 8! Though the covering on this amp is probably bookcloth rather than tolex.

[g1]

The OT wants to see 4 ohms.. while this may have been hard on it, it couldn't have caused the fuses to pop, could it?

Schematic you supplied shows 8ohm load. You said it blew fuses with or without tubes, so the load wasn't an issue.

[Bob Opera]

Schematic you supplied shows 8ohm load. You said it blew fuses with or without tubes, so the load wasn't an issue.

indeed, that was dumb question. I did not notice that this schematic showed two 4 ohm speakers in series, thanks for the heads up! For some reason I was sure that it had two 8 ohms in parallel. That is the only schematic i found for a solid state rectified Twin 8. It also specifies 6L6/6V6 as the power tube, whereas mine is powered by a 7591.