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| I got motivated... [message #30940 is a reply to message #30937] |
Fri, 11 March 2005 16:25   |
PakProtector
Messages: 935
Registered: May 2009
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Illuminati (2nd Degree) |
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I found a few with google, 1619 + amplifier. How simple is *THAT*? I saw a neat one with a tertiary winding cathode feedback OPTx. Still had loop NFB. And a triode connected one( at SE 2A3 power ). The 1619 in low percentage U-L with E-Linear drivers still seems like the best idea. I know it worked with mediocre OPTx, and with a good one, it ought to be stellar. The 1624 does have the glass envelope advantage... I am still trying to decide if a 40W core is better than a 20W core design. Or if a tertiary winding rig might be best. I guess it depends on how much you are willing to risk on the build.
regards,
Douglas
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| that's appropriate.... [message #30943 is a reply to message #30941] |
Fri, 11 March 2005 18:23 |
PakProtector
Messages: 935
Registered: May 2009
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Illuminati (2nd Degree) |
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as it was Gary's 47 amp which led me to the E-Linear connection discovery. I found that the amp ran into headroom troubles when we ran right off of the plate, hence the use of the screen tap for driver voltage. I did not attempt it with pentodes so there is likely not such a problem as with triodes. My amp is a bit simpler than that, but probably similar in performance( IMO, likely better, but I am biased, no? ). It does not have the direct coupling issues( but instead, capacitor ones ). there are a few differences in execution, but for thigs like filament TX choice, Gary has got it nailed. I also think 10k a-a is a better load for U-L connected finals. I am also doing away with the input TX. The cascode differential amp/long-tail-pair phase splitter will handle that better IMO.
regards,
Douglas
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| Re: I got motivated... [message #30944 is a reply to message #30942] |
Fri, 11 March 2005 18:30 |
PakProtector
Messages: 935
Registered: May 2009
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Illuminati (2nd Degree) |
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the 1626 is a small single triode. Its plate Z is ~2k5 at a reasonable O-P. It could be made to work as an amp's final, but there are better IMO. Type 45 among them( and I'm not much of a 45 fan ). this is another option for using the Guinevere power Iron, PP 45's. Same 10k PP OPTx, but a bit lighter a current load than a pair of 2A3's. 45's are a bit on the expensive side, especially for new production. If a small triode PP amp is what you'd like, let's see if we can find a cool, nearly unknown one for it. 3 or 4 sections of 5687 per phase are one neat sol'n...
regards,
Douglas
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| such a responsibility [message #30946 is a reply to message #30945] |
Fri, 11 March 2005 19:00 |
PakProtector
Messages: 935
Registered: May 2009
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Illuminati (2nd Degree) |
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this is getting too much like spending somebody else's money I think. I drew up a schematic on a big piece of paper for another chap building the 1624 amp. Let me see if I can get him to scan it for me so I can post it for inspection and commentary. If not, I'll draw up a few 8.5 x 11's in sections...
regards,
Douglas
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| Quack, quack [message #30948 is a reply to message #30946] |
Fri, 11 March 2005 22:05 |
colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
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Illuminati (3rd Degree) |
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I'm pretty much game for anything, but the 1624s are still seriously sexy looking tubes. They can be had for $12-20 a pop, so that's another bonus. Would love to see a schematic.....Colin
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