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In Reply to: Theoretics: PP vs PSE posted by thoriated_tiger on September 29, 2004 at 11:11:41:
Hey-Hey!!!,
PP of course. The inverting nature of a single tube element makes the creation of a 180-degree out of phase signal easy. There is no 'splitting' going on, more like creation. Anyway, PP also deos a bit of distortion cancellation of the soort which is far to easy to create in a SE stage.Does not have to be a mulit-grid output valve iether, the PP topology goes just as well with Triodes. If I needed 40 watts, it is easy, 60 is a bit more difficult, and 100 is going to require some interesting trix ( assuming class A, why bother w/AB1, it makes better use of the OPT anyway ).
live long and prosper,
Douglas
Beware the man who behaves deceitfully towards others, for there is nothing else to save you from his deceiving you
Follow Ups:
Yeah I know... phase inverter is the more correct term.So to your ear, you prefer a pushpull over single-ended?
I'm sorta the other way around -- I love the clarity of a triode, but also am addicted to the bottomless pit of power a pair of pentodes give -- so much headroom that my amp never clips, even with Herr Beethoven.
I guess I'm tossing an idea around in my head for a single-ended parallel and ultralinear pentode amp with no phase splitter and an all-triode front end. (!) My thinking: The less parts from input to output, the less places the music can get garbled at.
LTP or whatever so long as it's a twin nd in diff. amp mode.'Nearly' as good as a 'theoretically perfect' inverting interstage transformer alternative, and cheaper too.
and easier to fit to an existing classic being modded. IME.
Close as close to SE. IME&O. Next is to put a CCS on the output stage! NOT so simple BTA it still only has to be ONE.
WarmestTimbo in Oz
The Skyptical Mensurer and Audio Scrounger'Still not saluting.'
Read about and view system at:
That's my other alternative.. long-tailed pair in front of a pair of 34's. It's just so.. common ^.^ Mullard, Eico and a bunch of others.I'm not looking to update a classic, really.. this classic remains as-is. I'm trying to whip something out of my own. The problem is, the classics are so hard to beat.. grr. It's all been done. Or has it?
One thing I know I'll give whatever I make is one killer power supply, since this is my very own, it'll probably wind up being a chassis of its own, tube-regulated and most definitely Class-A.
One fer the PSU and one fer the amps themselves.this also allows you to go dual rail either after the mains trannies or a dual-winding one, or two,
And it lets you use metallised film polyprops, in the PSU. space.
Use chokes in ladders with caps, not just one choke per rail.
If you are going to use Valve rectifiers as well as regulators do parallel them, at least. 2 GOOD 5AR4's per channel, if we're talking pure class A and 30wpc or more.
Consider using SS for the heater/filament supplies, DC only for the gain stages, and maybe only for the input tube.
Don't use a lot of overall loop NFB if any, and use as much as you can stand around the output stage.
Definitely CCS, or use an IT as/for the phase inverters.
Wherever circuit tradition says use a half watt or whatever wattage resistor double it, within reason. Lower noise.
WarmestTimbo in Oz
The Skyptical Mensurer and Audio Scrounger'Still not saluting.'
Read about and view system at:
seehttp://www.turneraudio.com.au/
latest uses 3 X el34's or was it 4?, anyway's very very good.
his 13E1's in SE UL with a tickle of NFB were amazing, too. the divien Ella and Emma Kirkby's throats were in da room baby. And yes I am a singer.
WarmestTimbo in Oz
The Skyptical Mensurer and Audio Scrounger'Still not saluting.'
Read about and view system at:
I don't doubt it has been done -- I was wondering how come pse is so scarce as compared to pp. At least in the Land of Pentodes -- there are plenty PSE triodes out there.
PSE will require an air gap in the transformer. Bottom line, for the same wattage the PSE output transformer will cost more. The power supply will have to be better too since you get no cancellation in the OPT.Perhaps you would do even better with one of those real high voltage SET's. That way you could have one tube and the wattage you desire.
Regardless of what you decide on either type can make use of any type tube. You could have a push pull, 300B, class A amp, that I doubt you would/could ever clip with those Fortes.
..to voice the K-Horn. Brooks 12A, 2A3 in pushpull. He had about six-eight watts to work with.Since the forte's a little less efficient, a pair of 300s in pse or PP would be just about perfect. Should be what... 12-18 watts? Enough to play herr Beethoven *LOUD*. =o)
I don't feel confident enough yet to tackle something truly Teslarian like 845s and such.. kilovolt plates.. mmm.
I'm merely exploring different front-end topologies. I may build a PP 300 for myself. Or PSE, or tranny-coupled.. Triode back end, Pentode back end.. so many directions to go in. My goal is to learn. If I learn enough, I may even join this madhouse business called audio. ;o)
You could also try a PP 845 running ~750 volts with a 6k6 output. There are a few trix to both simplify and improve. Perhaps use a pair of DHTetrode 1619 to drive it. All sorts of things to do if you only need a few tens of Watts. Drive GM70's with 10's perhaps?
The E-Linear connection would also simplify your power supply. 10Y would also be a neat one to try. But if you're going to the trouble of DH 10 volt filaments, try a pair of 813's U-L, into the same 6k6 with E-Linear 1619's driving them. CCS-ed 5687 diff amp as the first stage...
live long and prosper,
Douglas
Beware the man who behaves deceitfully towards others, for there is nothing else to save you from his deceiving you
You probably live in midtown Manhattan, walk to work, and use your SUV to drive to the supermarket in Queens on the weekend.
Nah.. for horns I like mod to low power. 20 watts or less, depending on the horn.Still... just for giggles, it'd be a blast, ne? 1kv plates..yum! Nurse, the crash cart if you please..
I don't own an SUV, it is a Cummins Powered UV, and I would rather buy a SE amp retail than live in NYC.I am currently living quite comfortably on 10 or so WPC. The only guy I know with PP 845's up and running, has speakers at least 6 dB more sensitive 1W-1m than mine, and his amps run them full booogie...
you did set the similie up quite nicely.
regards,
Douglas
!
Beware the man who behaves deceitfully towards others, for there is nothing else to save you from his deceiving you
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