5814A in Foreplay 2

[Pfenning]

So I picked up some RCA Commando 5814A tubes thinking they were the same as a 12AU7. I installed them last night, and turned on my Foreplay. There was a loud hum from both speakers, I'm guessing in the 150hz range. Is the 5814A not the same as a 12au7, or did I get 2 bad tubes? Both channels have the same hum. I switched back to my cleartops and everything was fine.

Pfenning

[Jim R.]

Pfenning,

I've never had a problem dropping a 5814 in directly for a 12au7, so I'm guessing you've got bad tubes.

-- Jim

[Grainger49]

Your problem is not the 5814A.  I have used them often, they are a favorite.  Something else happened.  Post voltages.

I have a list of 12AU7 equivalents for FP 1 and 2 in this folder:

http://www.bottlehead.com/smf/index.php/topic,1027.0.html

These are all drop in for FP 1 & 2 so no problem in FP III.  Some that have higher heater current than the 1 & 2 can supply will work in the FP III since it has more heater current available.  Those are not on my list.

[najo49]

I agree the tube is the same as the 12au7,However I have noticed the same thing but it was a low level hum. In the end I decided as the facts were they are the same,that it was tube problem.