Amplifier schematic using EL81

[Datun Walnut]

Hi All,
Trying to make space in the house and to save marital strife, I'm just sorting through my boxes of valves. I've found a load of EL81s and I wondered whether to keep them for a future project of whether to let them go.
Does anyone have any links to an amp using EL81s please?

 

[tikiroo]

No links but the attached datasheet gives operating conditions for a 20W PP audio amp.

 

[Parafeed813]

The Philips EL6400 amp:
Philips 20 watt versterker EL6400

 

[Ketje]

Or, since you have alot of them, a PPP.
Mona

 

[OldHector]

What is the drawback of using an EL81, or even cheaper, PL81? It always seems to be such an unloved valve.

 

[nigelwright7557]

Hi All,
Trying to make space in the house and to save marital strife.

Do what I did and get rid of the wife, more room for my stuff now.

 

[Kay Pirinha]

Philips EL6400 (as yet said), EL6401 and EL6411 amplifiers come to mind.
Best regards!

 

[Parafeed813]

Do what I did and get rid of the wife, more room for my stuff now.

Can confirm that 😀

 

[duncan2]

What is the drawback of using an EL81, or even cheaper, PL81? It always seems to be such an unloved valve.

Probably because it was never designed as an audio tube but as a TV line output pentode and needs nearly -40volts on G1 as well as a top cap anode , not so good if you are trying to keep radiated hum low.


Wasn't a big contender in UK CRT TV,s as series heaters like the PL81 were in the vast majority , I found very few EL81,s in the TV,s I repaired .


OTOH-- some in DIY Audio like them-


EL81/6CJ6 operating point