Some Common Diode Forward Characteristics

[rongon]

Question really becomes' Why is the maximum stage gain required'.

One place would be the input stage of an RIAA phono preamp.

 

[jhstewart9]

One place would be the input stage of an RIAA phono preamp.

I did several input stages for low level magnetic pickups. Never needed max gain from the first stage.
During the Golden Days of vacuum tube HIFI one of the most common pickups was the GE Variable Reluctance.
The mono vers was cheap & reliable. The stereo version not much good at all.
Hard for some now to believe, it was possible to get more than passable results from a 12AX7.
Better with a 12AY7 or EF86/Z729. Real low noise with a cascoded 6BQ7.
I built this one circa 1956 while working at the R&D Division of Ferranti.
Mine doesn't have the expensive Triad input transformer.
Used it for a few years, its still here on the shelf. 🙂

 

[Merlinb]

Got any comparative measurements of D% to shew us? 🙂

Yes they're in my HiFi book, section 6.3.