Benson Ge Preamp schematic

[mcentee2]

Had anyone seen a GE Preamp schematic or layout for this yet ?

 

[SenfSenferson]

I don't have a Schematic but just build a Benson Preamp with Germanium for Q1. I just replaced the first Gainstage with a Rangemaster Type Circuit without negative voltage and tweaked it a bunch. Propably way of the original servo biased Benson Germanium but still a nice OD. The grey Resistors are for biasing and socketet. Here's a dodgy Perf Layout.

 

[Locrian99]

Benson has patented their germanium circuit design to my understanding. The say they do the temperature thing. So its kind of a no go for putting out pcbs etc of.

 

[Fama]

Benson has patented their germanium circuit design to my understanding. The say they do the temperature thing. So its kind of a no go for putting out pcbs etc of.

I was under the impression the patented part is the heating circuit so the germanium stays at a stable temperature. If it's just that, you could technically clone everything else and maybe get it to sound the same, except affected by ambient temperature much more? Or does anyone know if there's more to it than that?

 

[drew.spriggs]

Benson has patented their germanium circuit design to my understanding. The say they do the temperature thing. So its kind of a no go for putting out pcbs etc of.

The patent is for thermal stability - nothing to do with the rest of the circuit.

(It's also just using a thermocouple/heater to keep the temperature stable, which anybody can figure out themselves very easily).

Iirc the GE version is just the normal preamp with a temperature stabilised GE BJT as the first gain stage