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Re: Don't make my mistake

3/19/2005 12:20 AM
Dr. Photon
Re: Don't make my mistake
Annother pitfall is that some equipment expects pin 1 to be tied to the grid. I believe there was some amplifier for audio mixers or studio monitors or something like that that only connected pin 1. quite bad considering it was fixed biased!  
Unfortunately, i have an amp just like this. I was building a single ended amplifier in the Style of the Fender Champ. I had a 9 pin socket and an octal socket wired up in parallel (there was also a 7 pin socket, but that wasn't useful, especially since I gave my collection of 6AR5 and 6AQ5's to a friend when i built him an amp with those tubes) with a selector switch that allows you to select 130, 270, or 470 ohm cathode resistors. I had initially connected pin 2 to the grid, but an accident broke pin 2 on the socket! I thought I had to completely redo the thing, but then I realized that all of my EL84's had pins 1 and 2 connected internally. I still need to check all my tubes when I want to run EL84's