Thanks for the suggestions. As I said the idea is to have something to boost the 10W I have (KX2, IC-705) when doing SOTA from more interesting locations. In the past 5W SSB/CW from my 817 was more than adequate from Maedira/Canary Islands etc. But I would like something a bit more ability to command my frequency.
Of the MX-P50 or Micro PA50+, I think the MX-P50 is the better amp.
The 1959 Ferrari Columbo 250 (3.0L) engine was a masterpiece, compact, reliable, 240bhp in user trim, 310bhp in competition trim. They continued look for improvements, 275 (3.3L), 275 4-cam, 330 (4.0L), 365 (4.3L) etc. They improved on perfection! For the same reason, the MX-P50 seems ideal but if you don’t check, something may have come out since that is better/cheaper/lighter/whatever.
And this is why the 250 engine is perfect… watch all 7minutes and have an eargasm.
Several people suggested CB amps. I have one here (£5 new in the box at Blackpool) but as of yet it has no filters and I’m not sure if it’s biased OK for SSB. Good for 40W CW on 10m. I see that there are filters available from eBay for not much money and that may be a way forward.
And that’s not a bad suggestion. However, I have far too many HF radios, I’ve sold one FT-817 and the other 817 and a 706 are going on eBay next 80%-off-fees day. But I’ve not really spent £2000 in the last year on a KX2 and IC-705 to buy another HF rig which will get very occasional use.
Like Peter HB9PJT I’ve thought about using a PA from a scrap HF radio (with real biasing and filters). When I bought my Codan 8525B it came with an unused spare PA board that’s good for 125W but I do not know if it’s ok on 10m as the 8525B is only for up to 24MHz. (I’ve just found VK3ZYZ’s 8525b synth updates… another project to make). The circuit will be useful should I go this way.
I should never have sold my HL-45B but the cash offer was useful and was spent on toys I would use as I had no use for a 50W amp for an 817 at the time. There was one on eBay last week but I was thinking ahead and didn’t bid. It went for a steal, less than an MX-P50 sells for.
So I may seek out an MX-P50 to borrow (I only need it for a week) on a "he who breaks it fixes it " principle. Or I may buy one of my own. And I’ll be keep a watch for a Packer, maybe one that needs some TLC and repair.
EDIT: and there’s an MX-P50 on eBay that some Scouse monkey has blown up. Worth watching to see how much it goes for.