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Bob Daneliek built a PP 5687 amp very inexpensive. Awhile ago I had corresponded with him which is where I got the Idea for the 5687 pre and he said building the 5687amp with very high quality iron, then eventually converting to 2a3 is fairly simply done. Any thoughts? Or 6b4. Nice to contemplate a PP triode amp somewhere in the future as a logical extension of the 5687 project.
Hey-Hey!!!, There is a fairly easy way for a group to get good Iron. Copy it. All it takes is one sacrificial Iron. I did just this for my HY96 amp. Took a Peerless 20-20 Series and had it unwound by a practiced craftsman. Slighlty modified copies wound on a CNC machine for ~$110 each. This was a 40 Watt/10k a-a, S-265. I wish I had a 20-20 Plus to take apart, but that's for a later project. With a group, where a half dozen pairs will be wound the additional cost of an original( of what ever OPT is selected ) is not too bad. Some of the likely suspects would be the Acro TO-300, a 6k6 20W item, any of the 20W/5k Peerless 20-20 designs or OEM variants For a PP 2A3 amp, operating at a SE-specified point( 2k5-5k SE load), anywhere between 5 and 10k a-a ought to work. The SE load mentioned in RCA data sheets is 2k5, and I would suggest a 5k or 6k6 for the project. Take a look at the E-Linear schematic I stuck somewhere( Tubes maybe?), and figure putting the 'screen taps' at 10% or so for just little bit of NFB. If we use a 5687/6H6-Pi or the like, it won't be much. As to naming it( when it is finally done...) let's leave Merlin for a really advanced revision or another circuit. To mate with the Guinevere linestage, I would be suggesting Arthur of course. regards, Douglas
Sure, then we can leave Launcelot for a DAC. Merlin would make a great Phono Stage. I had already thought about a custom wound transformer and can't see any reason why not. I get the impression you like Tubes other than the 2a3 a little better for SE. Is that the case? Whaddya think about the big gun triodes 211/845? Thats my dream. Of course mercury vapor rec. tubes.
I agree with you both. I'd love to do something like a push-pull 2A3 for a power amp. As for names, Merlin is cool, but it might be best saved for a more ambitious project. Maybe one of the other names might be better. Round Table Characters
The cup from which Christ drank at the last supper.
repeat: I don't do SE. I don't think I will be doing SE anytime soon either. I have considered the 845 for the next amp, but *EVERYBODY* seems to have gone and built some version of an 845. Now the 813 is comparable in the filament requirement...and I have never even seen one built into an audio amp, let alone heard one. There are a few old commercial audio amps built with the 813. I suppose my statement ought to aply to DIY stuff. if it were easy, everybody sould be doing it. regards, Douglas Merry Christmas everybody!
Sorry. I kind of threw the question out in rhetorical context, not literal. Everyone is doing this projest for different reasons in quest of their own "Holy Grail.". I'm with you on the 845. To build one of those would just be so cool. Have a great Holiday......Colin
Colin you too; Have a very merry you and yours! Say did your better half get the earth mover? Is it Pink?