EZ80 or EZ81? What's the difference?

[Chiba]

I ask this question of you, oh gurus, as I recently got a box of EZ81 tubes from a friend of mine Out West and mixed in with them is a sole, lonely old Mullard EZ80.

I dug up a spec sheet (from Philips) on the EZ80 and it looks like the pin-outs are the same as the EZ81. Where the differences lie are in the voltage/current capabilities.

Where the EZ80 shows being able to handle a max of 2x350Vrms from the transformer (w/the current being 90mA), the EZ81 can handle a max of 2x450, with the current being 100mA. The spec sheets say that both require an 'Input capacitor of smoothing filter' in the value of 50uF.

Furthermore, the EZ81 sheet has a table for using a choke (valued at 10H), while the EZ80 does not.

So it looks to me like the EZ81 can handle more voltage and higher current than the EZ80, as well as being 'OK' to use with a choke, while the EZ80 can't.

Am I missing something? Is the EZ80 safe to use in an amp or should I toss it in the trash?

--chiba

[markh]

I think it'd work OK as long as you keep within the ratings. Might be a trifle lightweight for an 18watt with a max of 90 mA, but it'd work fine on a 6 watt.


--mark h

[Chiba]

Thanks Mark!

[cloudhopper]

Hey Chiba,

Mark is right on that. I'm using an EZ80 in a 12W build using ECL82's and it works fine but I wouldn't use it in an 18W. Some old Precision Electronics EL84 PA amps used that tube but they were running the EL84's very conservatively for long life.

Carl