tbray@watsol.waterloo.edu (Tim Bray) (03/19/91)
This is getting kicked around a bit in rec.audio, and it's certainly a high-end subject. IF you don't play vinyl, then it seems intuitively likely that a pre-amp box full of active componentry is less desirable than some sort of passive attenuation/balance/switching technology. Even if you play vinyl, the idea of a RIAA+head-amp box specialized for that function and producing line-level output might suggest the desirability of passive pre-amping. Or, it might suggest the viability of a truly high-end integrated amp - just a power amp with passive volume/balance/switching stuff on the front - this also eliminates one stage of interconnect - appealingly minimalist. Might even be room to save a few bucks here... I know for a fact such products exist. Anyone here using them? It said that there are all sorts of potential problems with impedance matching and the like. Feedback on that? Tim Bray, Open Text Systems, Waterloo, Ontario
rbars@hila.hut.fi (Rainer B{rs) (03/25/91)
In article <10339@uwm.edu> tbray@watsol.waterloo.edu (Tim Bray) writes: > >This is getting kicked around a bit in rec.audio, and it's certainly a >high-end subject. IF you don't play vinyl, then it seems intuitively likely >that a pre-amp box full of active componentry is less desirable than some >sort of passive attenuation/balance/switching technology. Even if you play >vinyl, the idea of a RIAA+head-amp box specialized for that function and >producing line-level output might suggest the desirability of passive >pre-amping. > >Or, it might suggest the viability of a truly high-end integrated amp - just >a power amp with passive volume/balance/switching stuff on the front - this >also eliminates one stage of interconnect - appealingly minimalist. > >Might even be room to save a few bucks here... > >I know for a fact such products exist. Anyone here using them? It said >that there are all sorts of potential problems with impedance matching and >the like. Feedback on that? > >Tim Bray, Open Text Systems, Waterloo, Ontario Several HiFi magazines have published building descriptions of passive preamps. The one I read (the Finnish magazine "HIFI") uses it as a reference. I will build one myself one of these days - as soon as I can afford a new power amp. The main problem seems to be building - or buying - desent volume controls. In my opinion, the type using a "ladder" of resistances is worth a try. The impedance matching should not be a major issue, since the wavelength in the cables is much MUCH longer than the length of the cables. If anyone of You engineers out there could post an easy-to-understand explanation of how impedance matching works, I wolud enjoy it. This is not my area.. Anyway, the thing is relatively easy to build, easy to understand, economic, does not pollute, so it should be perfect for the DIY-man. (and Your girl- or boyfriend will be capable of using it too :-) Rainer Bars Helsinki University of Technology Lab. of Engineering Geology and Geophysics ** Money? What money? You mean they will PAY me for THIS nonsense? **