El/pl 519
 

Hi.

I'm looking for ideas how to best make use of PL 519 in PP arrangements. ( not interesded in OTL's )
I'w been trying to find information regarding recomended B+, Ia and plate load.
I'm thinking triode strapped but maybe UL is the way to go...
Anyone got any ideas or schematics ???


// Niclas

If you're really, really ambitious, you might consider using these in a screen drive arrangement. In this topology, you tie the control grid directly to the cathode, then drive the screen. The tube acts like a zero-bias triode. Downside is that you need a driver that can source current, like a cathode or source follower. Upside is that you can run very close to class B without sacrificing linearity. With 2000 ohms plate to plate impedance and a 700V B+, you can get 150 watts out of a pair of 519s.

Go over to David Berning's website and take a look at the schematics for some of his older amps like the BA-150, EA-2100, and EA-230 to see a few implementations. In my amps, I use a source follower to drive the screens; Berning uses emitter followers or cathode followers, which are also good choices.

Re: El/pl 519
 

UL is not really good with the '509s. Tetrode connected with 450V anode, and 150V screen gives some 100W, when use 2.2kohm output transformer.
Another possibility to use it as triode (22-100ohms screenstopper necessary!). With 300V anode, and 2200ohm gives 30-35W, but it needs high driving voltage due the low mu. So for 100mA bias (class AB) You need about -75V for first grid. I made this amplifier, and it sound nice, even without nfb. This is possible because the low plate resistance.
I have some tested schematics for this valve, but I need time to scan it.

sajti

EL519
 

Niclas,
try this for SE:
http://www.geocities.com/bobdanielak/technoteNo33.html
or buy Bruce's Rozenblit book Audio Reality.You can find there sch. for an amp of 150 watts PP with EL519!

Regards,
Yugovitz