45 SE

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Cressy Snr
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#46 Re: 45 SE

Post by Cressy Snr »

steve s wrote: Wed May 05, 2021 11:32 am … I hope you still have it in one piece when we can have a session.. I would love to hear it.
I don’t think there’s any danger of this one being dismantled. :)
Pauls’s 45s have come and so has the Black Gate cap off Nick. The cap arriving, means there’s a little bit more work to do on the power supply later this week, but after that, we should be cooking on gas for a long time to come.
I was thinking, I should have built one of these years ago, when you could still get 45s reasonably easily, but then it wouldn’t really have worked as I didn’t have the speaker efficiency I have now.
Mind you, thinking about it again, those original Fostex FE108EZ Metronomes with the twin Ruark active subs, might have made a good combination if I’d configured some 45s to drive the midrange upwards and let the plate amps in the subs do the bass. Whether it would have worked satisfactory or not I don’t know; I might have been forever tweaking the bass levels, eventually getting fed up, but it would have been interesting to try.
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Ray P
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#47 Re: 45 SE

Post by Ray P »

Cressy Snr wrote: Tue May 04, 2021 9:52 pm Well I'm so entranced with 45s, I just had to make a couple of plinky plonk playlists from my iTunes library to show 'em off.
I like your playlist Mr. Plinky Plonk
Sorry, I couldn't resist!
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#48 Re: 45 SE

Post by Cressy Snr »

Ray P wrote: Wed May 05, 2021 9:38 pm
Cressy Snr wrote: Tue May 04, 2021 9:52 pm Well I'm so entranced with 45s, I just had to make a couple of plinky plonk playlists from my iTunes library to show 'em off.
I like your playlist Mr. Plinky Plonk
:mrgreen:
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#49 Re: 45 SE

Post by Cressy Snr »

OK,
Having Nick's 2x220uF, Black Gate WKz cap in the equation, I've changed the power supply to suit.
It's now a split power supply, using the BG can and the JJ can.
The output from the rectifier feeds a 33uF 400V oil can cap. After that it splits to a Sowter CB25 20H/50mA choke per channel.
Each 45 then has a section each, of the Black Gate cap, then the EF80s have the same arrangement on the JJ cap.
It simulates nicely in PSUD, so there shouldn't be any problem. I'd be grateful if the panel would look the proposals over:
45SplitPSU.png
45SplitPSU.png (96.59 KiB) Viewed 2777 times
I've ordered some nice quality components from HFC, which should arrive tomorrow at some point, so it'll be a weekend job to get it fettled.
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Nick
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#50 Re: 45 SE

Post by Nick »

Looks ok to me. I was thinking the simple way to try would be to use the black gate in your original power supply as the first cap that feed the OPT and then the last cap that feeds the driver stage. But the split supply may be better.

(from the change one thing at a time department)
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#51 Re: 45 SE

Post by steve s »

Thats on the lines of what I have built steve
Looks good, and should be better with more complex music
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Cressy Snr
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#52 Re: 45 SE

Post by Cressy Snr »

Thanks chaps.
I’ll do it in stages, first Nick’s suggestion then the split supply. It’ll then be easier to suss out what changes and what causes the change. I’m not the most scientific of people, which is why I asked for feedback on the PSU plans. I’d have just ploughed on otherwise.
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Paul Barker
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#53 Re: 45 SE

Post by Paul Barker »

Now you’ve entered a world where everything you change has a different sound. Good luck with that, it’s haunted me the whole time.

On youre thoughts above, I was cringing at 3 very different influences in terms of capacitors in power supply. I would try to simplify it and reduce the variety to polypropylene for the small first caps and black gates from then on. It’s so long since I’ve used black gates if I described what they did, it would be only a memory and much key information I’d possibly forgotten. Get used to it and live with it for a long time. There will come days when you wake up to new differences.

BUT, a WKZ is just another capacitor. It ticks a lot of boxes that make you enjoy it. But you might like something else differently. You don’t have to buy the Herb Reichert rhetoric. Don’t let it influence you. Find you’re own experience.

If I could try to collect some memories which some aren’t there as they’re forgotten and others aren’t reported as they were; also due to age.

The Black gate wkz is not an earth mover but it is subtle, however how much it is better is small. The pride of ownership and the knowledge of what Herb wrote demand something much greater. But strip away those influences of what you’d aspire to but can’t quite get. Give them time and some better things might creep up on you. But they’re sometimes so little and over subtle. I can enjoy polyprops or paper in oil just as much. They’re nice. But they over influence, less subtle. Less correct, but that doesn’t matter.

But don’t blend 3 cap types in one power supply. Just one view.
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Cressy Snr
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#54 Re: 45 SE

Post by Cressy Snr »

OK,
I’ll have a rethink over types.
Thanks for that Paul/Nick/Steve. To get this kind of feedback is exactly why I put the capacitor types on my schematic.
It’s even more reason to do the ‘change one thing at a time’ thing.
Looking at schematics for 45 amplifiers over the past day or two, it is evident from all of them that without exception, their builders will not let an electrolytic capacitor anywhere near their power supply.
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Cressy Snr
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#55 Re: 45 SE

Post by Cressy Snr »

The electrolytic cap aversion from the low power SET builders since time immemorial, is a major problem for my own amp design, and could render the split power supply dead in the water. There simply isn’t the room for split PSUs unless I use electrolytic cans and the WKz Black Gate.

A few questions if I may:

High DCR chokes (451R each if I go for split supplies.) Is it something to be concerned about or not?

Overall high levels of capacitance? 220+220+ 33+ 33uF desirable in terms of HT noise reduction? Undesirable because it slugs the rise time or does it? I don’t know.

I’ve got this gut feeling that high DCR chokes combined with high levels of capacitance are going to turn the 45s to mush. Or am I worrying about nothing.

There is far too much conflicting info about and I’m not savvy enough to be able to sift out what’s relevant to good SETs and what is dogmatic bullshit. So a few pointers would be very gratefully received.
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Nick
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#56 Re: 45 SE

Post by Nick »

Its a 45 Set, if you wanted to get worried about not following dogma you would have removed the pentode. Keep it simple, then change as you feel until its not improving. Me, I would do what I said before, replace the cap that feeds the OPT and its bipass cap with one half of the BG, and the cap that feeds the driver stage and its bipass with the other half of the black gate. Listen to it for a week, add the bipass caps back in, if better with blackgate, leave it in, if better with bipass cap leave them in. Then if you want try the split supply and if that’s better keep that.

If you want to avoid electrolytics, I have some shunt reg boards that you can try, but being shunt regs, they will increase the overall current demand.
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#57 Re: 45 SE

Post by Cressy Snr »

Cheers Nick.
I forgot about the pentode when I was having a moan. :lol:
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Nick
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#58 Re: 45 SE

Post by Nick »

I am not saying that there are not people who post stuff about amp design that are unbiased and honest but there are certainly some trying to establish a following by saying things that are attractive to those minds that like to be part of a cult/sect/clan/special people/etc. Given its impossible to know for certain which group any post falls into, treat them all as bogus. Do what works for you, try simple things, use proven engineering principles, listen, measure, enjoy. THERE IS NO MAGIC.

If a amp is great are playing some music but not others, decide if it matters, and if it does, consider having more than one amp. There are no awards for beating yourself up.
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#59 Re: 45 SE

Post by Cressy Snr »

Aye,
I take your point Nick. This is supposed to be an enjoyable pastime after all.
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#60 Re: 45 SE

Post by Wolfgang »

...use proven engineering principles... THERE IS NO MAGIC.
I was kind of hoping that the OPT topic would come up at some point because I am considering to build a 2A3/45 switchable SE amp based on a Loftin-White circuit.Shouldn't the quality of the OPT be #1 on the list if we talk about "proven engineering principles?
Or let me ask the other way round:Would it be a real SQ improvement using a Monolith Magnetic S-9/SA-9 ($350/$500 ) instead of an Electra print TM3KB ($145) for example? Wouldn't that have more impact on the SQ - like "magic" - than different caps, chokes, psu in general ?
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