Mazikrav, the First Watt F3, F7, F1J, and F2J all have input impedances of only 10K, which seems kind of low for use in conjunction with a resistor-based passive preamp such as your Placette. Although the potential downside of that will depend in part on the output impedance characteristics of your source components, which I suspect are favorable in the case of your solid state Oppo, and probably also in the case of your Sound-Smith phono stage.
But if you are considering going to a different amp, and envision staying with the Placette, it would be prudent to choose an amp having a much higher input impedance, e.g. 47K or more.
Also, fyi, if your Sound-Smith "The Voice" cartridge is the model having a rated output of 2.12 mv, and if you are using one of Sound-Smith’s 43 db phono stages, you don’t have enough overall gain when using that source with the Placette to be able to drive the F3 (or the F7, or many other amps) to their maximum power capability, at least on the vast majority of recordings.
Just some points to be aware of as you decide how to proceed. Good luck. Regards,
-- Al