Erik Mandaville Posted February 22, 2003 Share Posted February 22, 2003 I'm starting a new post here, with the hope of some increased light on Jack Eliano's (ok, and also -- in part -- Ron Welborne's)ultrapath linestage preamp. Mike: Having incorporated the 'Ultrapath' (a name in my opinion more 'catchy' than descriptive of it's function or purpose)bypass capacitor connection in my Moondog amplifiers (as Leo has also done), I am very interested in your possible construction project of the Ultrapath line stage. I know of builders who incorporate interstage and transformer coupling wherever possible, and I would be curious to know about your project and discoveries if and when you start to build. I did get the original Vacuum Tube Valley issue that contained the article and schematic for the Ultrapath linestage (and in a subsequent issue, the DRD Reactance amplifier), but can't seem to find it. Schematics for both are available on the Electra-Print website, I think. Please let us know as you progress -- and, are you planning on the conventional power supply or currently available battery-operated version from the Labs of Welborne? OK, now I get to talk about my dad, too... He uses a really cool setup for all his receivers and transmitters, which consists of battery power for everything, stored in very expensive Marine grade batteries, all of which is replenished by bright Arizona sunlight (I'd move there in a second if teachers had better salaries...) I keep thinking it would be at least a fun experiment to try this with audio equipment. Anyway, Mike, I'm interested in your prospective project! keep us up-to-date, would you? Erik Quote Link to comment Share on other sites More sharing options...
Audio Flynn Posted February 22, 2003 Share Posted February 22, 2003 Running off of batteries sounds interesting. Mapleshades a small producer of Jazz Cds uses batteries when recording to analog 2 track as i have read in the past. I thought it was a cool idea for a phono pre amp Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 22, 2003 Share Posted February 22, 2003 I was thinking of using the power transformer and the 5Y3 rectifier from a RCA 6BQ5 single-ended amp for the power supply. The power transformer has a 6.3 volt heater winding, to possibly power a pair of 6J5's, or two sides of a 6NS7. I like the idea of using two 6J5's for a left and a right side, than using both halfs of a 6NS7 for left and right. The power supply on the EP site schematic has a 7.5 volt heater winding running a 4 amp bridge rectifier, then a RC network to 6.3 volts. I should be able to run the 6J5 heaters off the RCA power supply trannie's 6.3 volt winding, it will probably require some adjusting however. The only thing holding me back is the EP L-3500 line out transformers or a equalivent with a 8:1 primary impedance that has respectable BW and linearity. And a 20 henrie choke in the PS. A couple of 40 mfd 440 volt oils for the ultrapath caps will be kinda spendy. The UP linestage mentions to use two chassis's for unpotted L-3500's, due to noise issues. So I figure I would just go ahead and have the Power supply and linestage on two different chassis's anyway. My geuss is it would save a lot of noise issue hassles. It's all speculation at the moment, I'll post if I do a linestage. The EP linestage circuit looks rather simple, this is what sparked my interest. Quote Link to comment Share on other sites More sharing options...
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