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I'm assembling a 6V6 single-ended amp drawing about 60ma each channel, using 6J7 as driver. The original schematics stipulate using 6X5, for each channel I guess. I have on hand 6X4, 6Z4, 6CA4, and those higher current types 5R4, 5U4, 5AR4, and CV378 but not 6X5. I suppose all of them are electrifically fit though those high current types are probably overkill. Andbody can share the experience on these rectifiers? Thanks.
Follow Ups:
No doubt in my mind - the 5AR4! Wonderful little tube. Even the dirt cheap Chinnese one's have worked just fine for me (nearly two year's service, 9 hours a day, 200+ days a year). Rated for 225 - 250 ma, so should handle both channels.
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Beware of tubes that say "Made in Chian" (that's what it said!)
If they can't print right, what kind of quality control they have?!
Just so everyone knows - for the 1,000th time - the current production Chinese 5AR4s are very good tubes. I have had zero problems with them. The Sovteks are fine too.Changing to a 5Y3 will lower the voltages throughout the amp, so you can't compare tubes. You are comparing amp circuits operating differently at the same time.
The CHIAN thing is pretty funny though. Back some years ago, a company that had the rights to the Indian motorcycle name was putting it on small 2 cycle bikes made in Taiwan. They were installing the Indian name decal beautifully, aligned just right, just the right location on the tank - but upside down! They didn't know what it was they were doing, they didn't know how to read English cursive writing.
I am also using Sovtek 5AR4s, which are reputed to be of better build quality than the Chineese made ones. I can't attest to that, however - only have a few hundred hours on the Sovteks. No problems so far. They cost only a few bucks more.
6SJ7,Black plate Mullard EZ81 (6CA4) or, if the Gods shine down upon you, the GEC U709. These boys MAKE the great 18 watt Marshall tone.
6X4 might be a bit weak for a 6V6GT SET amp, running at redline.
For octets, a good 5Y3GT will do the job. Bendix 6106 are worth hunting for---they are drop ins for the 5Y3GT.
Stevie,I suppose I can use a 6CA4 for 2 channels...?
And at red line is a 6X4 for each channel or both channels?
Thanks.
6SJ7,I belive that the 6CA4 (EZ81) will give much less sag (as in that dreaded "Cooper's Droop"), than the puny EZ90 (6X4).
For the sake of circuit simplicity and less worry of un-even wear---I'd go with one rectifier. Either the EZ81 or the 5Y3GT. And C-L-C pi-filtering, if you can afford it. There's no substitute for a good choke.
I got the duncap PSU calculator, but any idea how to use it?
nt
urrr... I got Ferranti 15H 70ma, Chicago 12H 105ma, Sansui 10H 100ma, what do you suggest?
Use the choke with the lowest DCR. I suspect the Ferranti is highest DCR.As for that rectifier tube, 5AR4 are rugged & my first choice or use GT Britain 6CA4.
urrr... not the one with highest inductance so as to block most ripples?aren't those with lower DCR (higher rated amperage) for power amplifier usage?
Both have high inductance. A low DRC is more important than a few Henry inductance at the two listed quite healthy values. To split hairs, if the larger one is within 10% percent higher DCR over the other, then use that one.
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