When I was looking to change the filament supply for my 300b’s many moons ago the Coleman regs were recommended as the best sounding of all the options. Currently have ac supplies, and there is a tiny bit of hum.
Soldering it all together and connecting it up is the easy bit. Need to find somewhere to put them.
All of this is the easy bit. Getting to understand what to connect and why is the hard bit 
This barely deserves to go in DIY, but there isn’t a “Poorly-skilled tinkering and occasional partial-defucktercating” thread, so…
I keep trying to give-up valves. They’re a perpetual pain in my arse - expensive, unreliable, contradictory, vague in data and a swine to test.
They can test fine and then prettily death-sparkle when you put them in-circuit, or they can light-up red-lights all over a tester yet work flawlessly in-circuit, and they can prance gaily from any one state to any other for literally no reason other than you looked at them wrong.
Anyway @chelseadave sent me some 12AU7 / ECC82s to try - four out of six of them came-up NFG on this:
I’ve had it 15 years, it has its limitations, at best it tells you if a tube will kill your kit, or not.
Probably.
Upside is it’s fairly quick and convenient, isn’t deadly in its own right, and doesn’t need a PhD to operate.
Anyway, something seemed off, Dave’s not a mug, and that was too many dead valves to make sense. So I grabbed some known-good ones and tested them - repeatedly. Never the same result twice, and often “DEAD!”. No.
So off me and the Silicon-chip Orange went to the room of wires and hot-pointy things. And apart it came. Trouble with logic chips is they either work, or they don’t. So for all that I spent time eyebaling for obvious fails, remaking and cleaning poorly-done solder joints, checking contacts and clearances, removing debris, &c, &c, the nett result was no-change. Too much SMD on the board for me to devote several days trying to test individual components which are probably fine anyway - 99% certain it’ll be a chip. Oh well… Shame.
So, into The Cupboard of Shame to retrieve this -
… which is 1969’s equivalent of the Orange: a basic valve health-check. It dies fairly regularly - the meter is sketchy and a proper ballache to get out and dismantle, and you need watchmaker’s skills, eyesight and hand-steadiness to sort some of what’s not quite right with it.
Its upside is it’s also fairly easy to use, and is compatible with a lot of quite late valve types (some nu-vistas, 6DJ8s, &c, &c.). It’s also point-point wired, which helps with reliability overall. Discovered today that a couple of switches are not 100%, so I’ll see if I can fettle or replace them next time I have some time, but I did at least get the meter working again.
Ran a few known-quality valves through it - good and dead ones, and all was as it should be, and lo! - Dave’s valves now test as good…
Too late to start rolling 'em, the Eclipse is a hard taskmaster, being German, so that’ll be kill-or-cure… 
I’d love to get hold of a late Avo or Hickock in GWO, but with the prices they now fetch, plus the fact they’d be way beyond me to sort out and calibrate, I continue to prevaricate…
Actually, I’d love to just shift the valve-monkey off my back for good, but the bastard fucking things JUST. SOUND. BETTER. …
GODDAMMIT! 
Yup. I imagine the circuit’s not published, and even if it was its functionality will depend on how it’s been programmed. These things are basically irreparable by third parties.
If you had some idea of how it might work you could insert a known good valve and check the voltages being applied to its pins with a multichannel scope. You might spot a glaring fault that way. But if the fault’s not glaring then you’re in for a very long haul.
Otherwise you could phone Orange in Borehamwood and see if they will help.
Thanks Graeme. I will try them, but my guess is that if it’s still supported at-all, they’d be bunging new PCBs in there at about £10 less than buying a brand-new unit.
I can’t find anyone holding stocks of new units.
They used to retail for £360 or so, which was an attractive price.
I see a ‘virtually mint’ (=used) one went for £820 on eBay a couple of weeks ago
Some desperate tech spending a decent-sized band’s money, I’d guess.
Still, if a working one’s worth that much I wonder what you might get for a ‘nearly working’ one ?
Buy an eTracer and be done.
I have a valve tester that I don’t use. Come to that I’ve never used it.
I think this, Subscribe to back in stock notification, and the fact there is no way to put one in the basket, for purchase, might be a clue.
Posts #2 and #3 here
say it’s been discontinued, perhaps for a few years. GAK reckon it’s gone west too
Can’t be expected to look that far in to stuff.
Let me know what it is if it surfaces please Dave 
easy bit
not so much
We might need a chat at some point about a BTJKD9000
Fucking strange bird-table.
Fucking strange birds.
“Tell me, my good man, do you sell standmount speakers ?”
