45 SET

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simon
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#46 Re: 45 SET

Post by simon »

Yeah, perhaps worth mentioning to Mo that my version of storing isn't the same as Nick's. Mine's more about recycling rendering the original non-existant :lol:
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Nick
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#47 Re: 45 SET

Post by Nick »

Given the leaking roof my method is not that different.
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Paul Barker
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#48 Re: 45 SET

Post by Paul Barker »

Leaking roof is high need to Maslow for sure,
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IslandPink
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#49 Re: 45 SET

Post by IslandPink »

Nick wrote: Sat Aug 13, 2022 1:51 pm Given the leaking roof my method is not that different.
At least this should stop your mind from wandering where it will go.
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Nick
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#50 Re: 45 SET

Post by Nick »

Yep I should fix that hole in the roof :-)
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andrew Ivimey
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#51 Re: 45 SET

Post by andrew Ivimey »

Not far away from fixing a hole in the roof is, of course, the hole in my shoe that is letting in water. This song has the brilliant voice over from a little girl who likes really loud rock music. Priceless!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
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andrew Ivimey
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#52 Re: 45 SET

Post by andrew Ivimey »

Anyway, I'm pretty sure that Mo and I haven't spoken to each other in about five years.....might be time for recycling?
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
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pre65
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#53 Re: 45 SET

Post by pre65 »

Last time I spoke to Mo he was knee deep in EMT turntables.

It was a long time ago.
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#54 Re: 45 SET

Post by Cressy Snr »

andrew Ivimey wrote: Sat Aug 13, 2022 3:42 pm Not far away from fixing a hole in the roof is, of course, the hole in my shoe that is letting in water. This song has the brilliant voice over from a little girl who likes really loud rock music. Priceless!
Aye, she’ll be around my age now.
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andrew Ivimey
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#55 Re: 45 SET

Post by andrew Ivimey »

That's a thought eh!
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IslandPink
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#56 Re: 45 SET

Post by IslandPink »

"...featuring a spoken-word midsection by Chris Blackwell's stepdaughter, Francine Heimann.."
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Paul Barker
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#57 Re: 45 SET

Post by Paul Barker »

Simon, I very much enjoy my amp with a 126C interstage. So Ive picked up the late Sakuma San ideas. Obviously a very poor man’s example.

Image

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Paul Barker
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#58 Re: 45 SET

Post by Paul Barker »

At the bottom three rows of the Hammond page, the other 126 variants may be of interest. All three are bifilar. If you subscribe to the concept (which I don’t have an extreme opinion about, neither an argument for, I find 15mA drives parallel 801a’s perfectly well) more current than 15mA would be required to drive a 45 output valve, you can use the 126B for the driver and take the operating point from column 1 of the valve data Ive posted. Certainly you would slug it. (Extreme ideas on that 126B variant would be to also use it to dc block on the output as an output valve load, then have a permaloy autoformer wound to match the hammond to youre speaker impedance. But set that aside for now, Ill hopefully experiment in that area many years hence, ill not recommend anything I haven't tried).

45//45 sorted.

What to use as voltage amplifier? Since you get some gain from the driver, youre half way. For the output valve at 275/36mA you need 56 volts peak, with error margin of say 30% so it never clips at driver = 73v / 3.6 = 20v peak from VA, carry on the excess philosophy by 30% again = 26v. If youre source outputs 1v peak you need a A (‘A’ctual gain derived from mu and other factors) of 26. Not hard with the modern valves available, but to stay in Sukuma camp he would have used step up interstages at great expense. Myself Id come out of Sukuma at this point. You could do well to use Marks suggestion of pentodes at this level, where a gain of 26 is easily achieved and the blend of distortions people like.
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Paul Barker
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#59 Re: 45 SET

Post by Paul Barker »

I may build a mono breadboard for fun since I have whats required and to be honest breadboards are so much easier to do. It may come to Owston, but no pressure on me!

I forgot to mention if using ST Id go with right column operating point, if balloon Id back off to the middle section. I already know which sounds best.
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simon
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#60 Re: 45 SET

Post by simon »

Thanks Paul. I had mused on ITs, and have an old 5k AE pair I got from Will a long time ago, and some Onetics custom made for 10Y, 10k I think. 4P1L might be a nice driver, but complexity has shot up. Will do some more thinking.

I was considering running the 45s at something like 250V and 30mA anyway. They're ST but they're probably older than me so thought I might be kind to them.
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