5763 = El84?

[sorenj07]

The basic question. Saw 5 on the 'Bay for $11 or so including shipping. Can I use these as EL84's? The information on these is sketchy at best. Here's a nice picture showing the similar-sized plate structure, though that of the 5763's is nearly continuous. P.S. those blue blurs in the background of the macro shot are a nice shiny pair of 7600 ohm 25W Edcors. I'm building an amp for a friend's family and at the moment have some 6P14P's that might or might not be working, and now this "sleeve" of 6 (the seller threw an extra one in) that could hopefully work.

The amp will have a B+ of 385 or so, and my cathode resistors are 182 ohms and half of a 100-ohm pot per PP pair. My bias point using an EL84 UL datasheet is ~240V plate, 35mA. Dissipation is 8.4W. I imagine that to use the 5763's I'd want some healthy grid stoppers to the inputs. Would I also want to put big screen resistors? One PDF I read suggested that for a 300V screen grid voltage in RF use, a 12.5K resistor ought to be used. Finally, I'd probably strap pins 3 and 7 together, namely the 3rd grid from the cathode and the cathode, right?

Thanks!

As promised:

[coresta]

Hello, yes , i asked myself the same question and have just done a test on my Metrix toobz tester . The 5763 seems to be a perfect sub of the EL84 . One caveat : It's a real TETRODE, not a pentode but, as you previously said , original RF. So the G1 might be a reinforced one , against secondary emission in C class . I've sold myself 50 pieces on epay in the last months as i have a huge stock of them ... So it is worth a try . ON AA , a guy claimed he tried it in an AF amp without any problem. I have the project to build an OTL amp with 24 5763 / channel Yes 48 5763 in STEREO

[sorenj07]

Originally posted by coresta
Hello, yes , i asked myself the same question and have just done a test on my Metrix toobz tester . The 5763 seems to be a perfect sub of the EL84 . One caveat : It's a real TETRODE, not a pentode but, as you previously said , original RF. So the G1 might be a reinforced one , against secondary emission in C class . I've sold myself 50 pieces on epay in the last months as i have a huge stock of them ... So it is worth a try . ON AA , a guy claimed he tried it in an AF amp without any problem. I have the project to build an OTL amp with 24 5763 / channel Yes 48 5763 in STEREO

Sounds great! Also, I found this in a PDF:

tp://www.vacuum-tube-shop.com/vacuum-tube-shop.pdf

"
We are made amps whits can pull out 20W audio power whit one
pair. Transformer designed for EL84 can be applied to quartet
of 5763. Matched quartets should be no problem.
"

Aside from the Engrish, looks promising! I'll definitely give them a shot.

[SY]

Dumb question: since you can get excellent quality real EL84 for about the same price, why do this at all? Or was that $11 for all five rather than $11 each?

[sorenj07]

$11 for six, the guy threw in a sixth one on top of the sleeve I bought. that's really the only reason... I saw an EL84-ish power tube, checked and saw its 13.5W plate dissipation, and BING! ordered it.

[SY]

Got it!

[Poindexter]

Who's your icon, SY? He looks like a Gilbert Shelton character.

Poinz

[SY]

Exactly. Phineas Freak of the eponymous Brothers.

I'm a major Wonder Warthog fan. Philo T. Desenex, the Hog of Steel.