Question about power tubes... KT88



It looks like one of my KT 88's in my ASL Hurricanes is not working properly. I noticed this when I went to bias the tubes and this one tube came up as 0.0. I changed tubes (V2 for V3) and the "bad tube" read 0.0 in the new socket.
However, it still lights up and the sound is still fine? What's up??
rwd
Rwd,

I would guess that the pin for the plate is burned out but the heater elements are lighting up. Note that each pin on a tube provides a different function. This tube is most likely not drawing any amperage.

I would recommend getting a reasonably priced tube tester that checks for shorts and transconductance.

Steve
Steve, I guess in this case it's enough just to check continuity with simple ohmmeter or DMM instead of breaking the bank through a dedicated tube tester.
Point well taken.

However, a decent tube tester can be had for under 200 on Ebay, if someone does some basic research. I picked up a nice unit that has allowed me to check the condition of the tubes in my ARC / BAT equipment. I also discovered a shorted 7308 tube that could have eventually caused a problem in my amp.

The ASL Hurricaine contains a total of 22 tubes (16 KT-88 & 6 6SN7's. I would want a way to check for the condition of these tubes periodically in a reasonable amount of time.

Nice amp, I just heard it over at Holme Audio (Chicago area) hooked to to a pair of Coincident Totals.

Anyhow, just my opinion - love this hobby - the opportunity for new stuff never ends. Sorry if I blabbed too much.

Steve