SUT for AT-OC9XSL?

Staying under 300 may be a tough call. If you look at the vintage step ups from 1970s through 1980s they seem to start around 450 and up. You may want to consider a ned clayton base and buy either cinemag transformers or the OJAS transformers which will work well. The combined total will push you over your 300 dollar price point by 150 to 200 bucks. 

With no SUT, you have a net of 68db gain, which means the cartridge output will be multiplied by -2500X. If your cartridge makes 0.4mV, the output to the amplifier from the linestage will be about 1.0V. Adding a SUT is overkill. Try without.

@lewm if that were true, wouldn’t I have to have the volume on the line stage way lower (due to excessive gain) than my other sources? The way I have things set right now, I keep my volume at about the same position as my other sources. 

Can you be more specific? I am not sure what you are trying to convey. For example, "way lower" for what? Since your CDP or whatever other high level sources you use is likely to put out at least 1V in signal voltage, generally up to 2V, I would guess that your linestage volume control is mostly attenuating those high level signals. Whereas with the 48db phono driving the 20db linestage, and if you like your music loud, I would guess you would have to turn up the volume control more than for your high level sources. Have you actually listened yet to the 48db Hagerman with no SUT?

Assuming the signal of the turntable (because of the SUT) is much higher than it should be as it enters the line stage, the amount of gain (volume) you would use on the line stage preamp would be lower than normal correct? Let’s say my CDP inputs a signal of 1-2V, wouldn’t the turntable signal of the turntable be markedly higher than that (hence what makes it excessive gain), causing me to have to turn the gain (volume) on the line stage way down when on my turntable input to compensate for the additional gain that happens upstream of the line-stage? in other words, the the volume controls gain on the lineage right? So if the turntable signal is much higher than 1-2V (because of the gain in the SUT and Phono-pre combined) then that source would need less gain (a lower volume position) in the preamp line stage than other sources which are not amplified much before the lineage?