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Hi,
Well you could do something similar to the 6B4G amp, namely a low mu triode followed by a phase splitter IS and that's all there is to it.
The triode could be any low mu triode you like, you're loosing some gain in the IS but that's no big deal.
Tack a pot on the front and bingo, you now have a preamp, and headphone amp and a miniwatt amp all in one box.
Cheers,
Hi,
Well you could do something similar to the 6B4G amp, namely a low mu triode followed by a phase splitter IS and that's all there is to it.
The triode could be any low mu triode you like, you're loosing some gain in the IS but that's no big deal.
Tack a pot on the front and bingo, you now have a preamp, and headphone amp and a miniwatt amp all in one box.
Cheers,
Richard,
i amcurious as to why you need 5v on the output when your amp goes up to 4v? wouldnt the full 5v input drive the power amp out of A class operation, into AB and B? im also curious why you're using output tubes for a preamp, especially when youre going to be running it through a solid state amp after that anyway? just curious, dont mean to sound harsh.
i amcurious as to why you need 5v on the output when your amp goes up to 4v? wouldnt the full 5v input drive the power amp out of A class operation, into AB and B? im also curious why you're using output tubes for a preamp, especially when youre going to be running it through a solid state amp after that anyway? just curious, dont mean to sound harsh.
well... i'll probably end up just using my 6B4G PP amps instead....
I kinda like some headroom on my pre-amp... and thats why I have said voltage gain of around 5.
Are there any good higher mu / lower plate resistance DHT out there??? If I go with 46's then mu increases, but plate resistance increases....
txs!
I kinda like some headroom on my pre-amp... and thats why I have said voltage gain of around 5.
Are there any good higher mu / lower plate resistance DHT out there??? If I go with 46's then mu increases, but plate resistance increases....
txs!
Re: power supply
Yes, I thought someone would say that. I think you'd be better off thinking of any hum rejection as icing on the cake, rather than relying on it occuring. And since I would never design a push-pull amp without good PSU regulation, and plenty of capacitance - it really is not any simpler that I can see.
316a said:
Yes, I thought someone would say that. I think you'd be better off thinking of any hum rejection as icing on the cake, rather than relying on it occuring. And since I would never design a push-pull amp without good PSU regulation, and plenty of capacitance - it really is not any simpler that I can see.
DISTORTION AND PSRR.
Hi,
Wow, two miracles in one day.
You're absolutely correct, Joel.
Moreover the PP needs to be well balances for this to happen so if people think they can get away with poorly designed PSUs because they're feeding a PP stage they'd be walking on thin ice.
Same goes for the distortion cancelation in PP too, no perfect balance no pay.
Cheers,
Hi,
Wow, two miracles in one day.
You're absolutely correct, Joel.
Moreover the PP needs to be well balances for this to happen so if people think they can get away with poorly designed PSUs because they're feeding a PP stage they'd be walking on thin ice.
Same goes for the distortion cancelation in PP too, no perfect balance no pay.
Cheers,
Re: parafeed?
PSRR will be better, but it will be better again with a CCS.
I like the PP parafeed idea, but why not try it with some 6C45's? One stage, low O/P Z, cheap, grunty and quite nice sounding, with some reporting it as good as a 45. For giggles I'm playing with some of these as a small (2w) poweramp, initially using another OPT for chokes, but if I like it, some v4 PMCCS. It would be running now, but I forgot to get some gridstoppers yesterday and will have to mailorder now.
Cathodes to B+ for the WE/ultrapath cap. For the blocking cap, either side of the primary will do, but if you can seperate the primary windings on the OPT, I'd put it at the centre, just because I like symmetry.
Lynn Olson has made some interesting posts about the WE/UP cap on Tube DIY at AA in the last few days.
RichardJones said:
PSRR will be better, but it will be better again with a CCS.
I like the PP parafeed idea, but why not try it with some 6C45's? One stage, low O/P Z, cheap, grunty and quite nice sounding, with some reporting it as good as a 45. For giggles I'm playing with some of these as a small (2w) poweramp, initially using another OPT for chokes, but if I like it, some v4 PMCCS. It would be running now, but I forgot to get some gridstoppers yesterday and will have to mailorder now.
Cathodes to B+ for the WE/ultrapath cap. For the blocking cap, either side of the primary will do, but if you can seperate the primary windings on the OPT, I'd put it at the centre, just because I like symmetry.
Lynn Olson has made some interesting posts about the WE/UP cap on Tube DIY at AA in the last few days.
hmmm....
Well,
I am undecided now....
Still want to use the 71a's.... Push pull Class A. input tranny and output tranny.
If I use a step up phase splitter input tranny, don't I have to be careful about excessive miller capacitance reflected back from the 71a's?
OK... anyone out there, point me to 2 transformers that I can use with the 71a that will give me a total volateg gain of around 7.
Balancing the 71a is not an issue and will be delt with.
Thanks!!!!
Well,
I am undecided now....
Still want to use the 71a's.... Push pull Class A. input tranny and output tranny.
If I use a step up phase splitter input tranny, don't I have to be careful about excessive miller capacitance reflected back from the 71a's?
OK... anyone out there, point me to 2 transformers that I can use with the 71a that will give me a total volateg gain of around 7.
Balancing the 71a is not an issue and will be delt with.
Thanks!!!!
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