6C45 phono input only?

[mashaffer]

I recall either SY or Eli recommending 6C45 for phono preamp use. It is an interesting tube for sure according to the preliminary research that I have done. I am not sure that I want to try to build with it in the near future as I do not have a scope handy but if one did would it make sense to use the 6C45 only in the input stages and use more pedestrian tubes such as 6N1P and or 12AY7 for the following stages? Probable topology would be three stages with 1/2 of the passive RIAA in between each stage.

How about LED bias for the 6C45? Any advantages or gotchas in that kind of bias with a hot tube like that?

mike

[SY]

Probably Eli. I've had little experience with it other than some benchtop measurements as a cathode follower, where it performed very well. On paper, the specs look pretty good for phono use, but the D3a (which I use) looks even better- higher mu, lower equivalent noise resistance, and it can be run at lower currents (I use 20mA in the first stage).

[Eli Duttman]

I've commented about the 6С45П (like the 5842) being "an in box oscillator", but I've never discussed using it in a phono preamp.

Rozenblit uses cascoded sets of the 6С45П as the 1st gain block is his phono stage design.

FWIW, I think that the 6GK5 will do all that's necessary in the 1st gain block of a phono preamp, with far fewer headaches than "firecracker" triodes cause.

[mashaffer]

Thanks Eli. Other than not being a current production tube it looks quite nice. Good price too.

mike