Will VPI's Classic 3 sound much better with a SUT?

Jason, you might review your own early posts here. You consistently stated that an MC phono stage adds 10X gain. Now I see that you meant to say that a SUT typically adds 10 X gain.  If so, ok.

For only 60db gain, I'd want a cartridge with a bit more than 0.5mV output. And tablejockey, I am sure that was a typo but my point is that 60db gain from an 0.3mV source gives 300mV or 0.3V.

Jason, do you really believe this?: "Most mc stages amplify a mc cartridge’s voltage TEN times for use with a typical phono stage!" Because most MC gain stages supply at least 60db of gain to the signal, and frequently much more than that, which counts for a lot because "db" is a logarithmic quantity. For example, 66db is equal to twice the gain seen with 60db or ~2000X increase in signal voltage. So the baseline 60db (which is what the Fosgate happens to supply) is equal to a 1000X gain in voltage. There are numerous on-line calculators you can consult, if you insist upon your particular belief system. It’s OK to be in error, but once the facts are given you, accept them. And as far as your pointing out that 0.3 X 1000 = 300, that is correct, but you left out the units:  0.3mV X 1000 = 300mV = 0.3V

Furthermore, like I said above, if MC gain stages could supply only a 10X increase in cartridge gain, the analog signal chain would not work; "3mV" that you propose to be the result of multiplying the cartridge output times 10 would not even drive an active linestage, let alone any amplifier. And I gave you the reasons why I think the Unison has only a volume control for a linestage ahead of the amplifier section.

Vinylfun, The version of the Unison Unico that I looked up (in the context of a Stereophile review) has only one tube, a 12AX7, instead of two 12AU7s. In either case, the tube input stage drives a MOSFET output stage, so far as I can tell. In your amplifier, one of the two 12AU7s may be used as a cathode follower, which adds no gain. In the review, there was no mention of an op amp. I imagine it is used for phono, if the Unico has the optional phono section, but I certainly could be wrong.

Jason, I don’t know where to begin. But 60db of gain provided by the MC stage in the Fosgate equates to a 1000X voltage gain, and a 10X gain that you claim would be insufficient for any phono stage ever. 0.3mV multiplied by 1000 = 0.3V

Also, I didn’t figure in the gain from the linestage because I cannot find any information on that and because most integrated amplifiers don’t add linestage gain. So I’m guessing the linestage (which is probably just a volume control ahead of the amplifier input stage) adds no gain. To support that assumption I found that the UR has only one tube that drives its mosfet output stage. That leaves no gain device available for any sort of linestage gain.

You don't say why you are thinking about adding a SUT to this system.  That would help.  Also, as a rule you don't match a SUT to the TT.  The TT doesn't give a hoot what SUT you choose to use, and vice-versa, but I understand in this case that the Bob's Devices SUT can sub for the VPI cable junction box. (Couldn't any SUT do that?)  Anyway, your Cadenza Black makes 0.3mV (at 1kHz at standard velocity) and your Fosgate is said to provide 60db of MC phono gain. That's a 1000X increase in voltage gain. So that means the Fosgate feeds 0.3V to the Unison Research amplifier.  Most integrated amplifiers do not provide much if anything in the way of linestage gain, so I guess the total signal voltage to drive the amplfier section is 0.3V. I cannot find the input sensitivity of the UR amplifier section, but 0.3V is in general a bit low to drive a typical amplifier to full output. So, can it be that your sound is a bit lean?  Is that why you are thinking about a SUT?  In any case, if the sound is a bit lean and you are turning up the volume control to achieve anything near satisfying levels, then yes, you might be better off with a SUT driving the MM stage of the Fos.