ECL82 SE

[pre65]

WAD did a lively design and Neal's your man for that.

Did he not bring it to Owston many years ago ?

[andrew Ivimey]

Yep.

[simon]

Right. I've been round in my usual circles of indecision with this. I spent quite a lot of time working out physical arrangements in AutoCAD as it's tricky squeezing so many chokes in to a compact space. Then I worried about proximity of all the iron and wondered if I really need to breadboard it. Then I lost impetus. Then I found some inspiration again and went round the loop of indecision again a few times.

Loop {
Build a Steve-style ECL82 spud amp with folded ally chassis and wood cheeks for fun
I need a HT PS, I know I have a handy Salas SSHV2 shunt reg all built and ready to go
Oooh, two channels is right on the edge of shunt reg, perhaps I need two
I have 2no. SSHV2 if needed. That needs a different chassis though.
Do I need to breadboard it?
I know, if I'm going to use a solid state shunt reg why don't I use a compact SS CCS instead of all those chokes
Oh, but then it's not James' amp with the magic of the chokes
Right, back to chokes
LCLC HT PS for ease?
LC with a split to two further LCs, one per channel?
Wow, all these 10 or 12 no. chokes take some accommodating, will they interact negatively?
Perhaps I need a more traditional "wood box with top plate" style amp
Do I need to breadboard it?
But then it's not a Steve-style amp
Pause
}

I take my hat off to you Steve that you build these things so quickly.

[simon]

Out of interest does anyone have a copy of the WAD ECL82 amp circuit? Nothing's turned up from a web search.

[pre65]

Out of interest does anyone have a copy of the WAD ECL82 amp circuit? Nothing's turned up from a web search.

I built this amp some many years ago, and I still have the stand alone PSU for it, but modified for different voltage requirements.

I have the WAD (or WD) Gold CD rom somewhere, will try and find it, but it won't be till tonight as I'm just leaving to see Mum in hospital.

Greg is normally "the man" for WAD or WD amp paperwork.

[pre65]

There is info on a niche audio forum.

https://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=145

see post 6.

[Nick]

Thats not the WD one.

[pre65]

Thats not the WD one.

Mia culpa !

It's my age.

I've dug out the Gold archive CD, will check tonight.

When Simon mentioned lots of ckokes that skewed my thought process.

[Greg]

Simon, just sent the build instructions and diagrams by email to you.

[Paul Barker]

Hmmm, I've lost my Sound Practices CD so don't have a copy of that 45 CCS circuit, well that's probably a good thing.

I lost mine, its greating.

[Paul Barker]

Sorry, not EL82, it’s EL822. This is a 13 watt dissipation pentode and Vade Mecum gives triode curves. Hasn’t enough in common with EL84 but it would be a lot cheaper, has similar gm 13ma/volt mu 23 the data on triode connected isnt provided but the curves are given showing 13 watt dissipation.


Found nos Mullards on ebay £8 plus £5 postage.

[simon]

Simon, just sent the build instructions and diagrams by email to you.

Thanks Greg

And Phil, thanks too. You can stand down

[simon]

Hmmm, I've lost my Sound Practices CD so don't have a copy of that 45 CCS circuit, well that's probably a good thing.

I lost mine, its greating.

It must be somewhere in my very many CDs, but goodness knows where

[Paul Barker]

Screen is ok at 250v so at 250v 3k5 opt (same as el84) bias -7 50mA gives 1.97 watts.

[Paul Barker]

Just spotted can do 275v triode mode probably get 2 watts.