Re: Valve preamp.
There is every flavour of RIAA topology. Either fully in the feedback loop, either around the input stage or after an initial flat gain block. Or a mixture of feedback and passive. Or entirely passive, possible split with a buffer in between.
I can find no rationale for going passive. Active RIAA around the input gain stage definitely wins with S/N ratio and overload margin. However, having tried all sorts of EQ arrangements, I have ended up with passive. For some reason it sounds more musical. And at normal listening levels you need to put your ear almost at the speaker to hear any hiss (on a moving coil cartridge with 300uV at 5cm/sec output)
Daft isn't it? But there it is.
Craig
|