Reconfigure Phono preamp for other use ...

[Todd Hepler]

I have a late 50's olympic am/fm/phono console that the owner wants the phono input converted for use with his sirius satellite receiver.

The tube that is currently in there handling the RIAA equalization is a 6SC7 dual triode with the common cathode, complete with grid-leak bias.

Does any one have any suggestions as to a drop-in circuit using the existing tube? Would a cathode follower be a good chioce over two stages of lower-gain amplification?

Any and all input appreciated.

Thanks,

Todd

[tboy]

Probably the first thing I'd try is yanking the phono preamp tube and hooking the sirius straight into the power amp, but I'm lazy.

[Todd Hepler]

Thanks tboy, I never considered that - think there would be enough gain going straight into the PI?

-Todd

[tboy]

...think there would be enough gain going straight into the PI?

Maybe. That's why it's the first thing I'd try - to find out if the sirius can drive the power amp to full output on it's own. You'd want to test for any DC present at the PI input first, and use a coupling cap in between if there is. Find the terminal(is this thing stereo?)s on the phono/tuner selector switch where the phono preamp hooks in, and swap the wires from the preamp with the phono jack input wires; then you can switch between the two and see if the levels are comparable. If the sirius is too low, then you can think about modding the preamp to add enough gain.