Pre Amps?

[Roger A]

[quote=petercom]

At present, due to the valves we are planning to use, we are going to have to stretch the cases vertically, or have the valve tops poking out the top (if anyone has views on this let me know as we are designing the case now).

I think it is fair to say that I am not a fan of cathode follower, particularly in a preamp output where the load dependance can be a factor. I know it has solved the occasional hum pickup problem in the pre2, but you won't be seeing it in a WD Pre3! Neither will we have the hum pickup problem as the output stage and transformer are going to be far more advanced in conception and performance. And we are also re-designing the moving coil step up transformers for incredible performance from low output mc cartridges.

[quote]

I wouldn't particularly mind whether the valves showed through the top or the case was higher though it would be useful if the height is such that it will still fit on a normal height equipment shelf. Just a thought but as they are small signal valves could they not be mounted horizontally?

With regard to the output configuration, I have seen adverse comments on cathode followers before. Using transformers seems a cleaner way to go especially if the susceptibility to hum pickup in the PreII can be avoided. One plea I would make is that the output is designed to be stable into long leads and low as well as high impedance power amp inputs so it will be truly universal and allow the siting of power amps, valve or solid state, close to the speakers. (It will also allow the use of active speakers - I admit a selfish interest here with my Meridian M2s with an input impedance of 9k ohms). Again, the use of transformers should be a good way of ensuring this.

Roger