Best Full-Function Preamplifier

I seriously disagree with those who suggest one is best off with separate phono and linestages.  (And by the way, the term "preamplifier" historically assumed a linestage and phono stage on one chassis.)  Here are the advantages of an all in one unit: (1) The signal runs through one fewer pair of inputs and outputs and one fewer (often very expensive and always SQ affeccting) IC is required.  This point alone is nothing to toss aside as not only do ICs add flavoring, at best, but also the connectors are a source of subtle alterations in SQ. (2) Just because the phono and linestages are on one chassis does not necessarily mandate a single power supply.  The best all in one units have a massive power supply on a separate chassis and often that box incorporates separate supplies for phono and linestage, respectively, and (3) having the phono and linestage on one chassis also gets rid of an output coupling stage entirely or at least permits the use of a much lower value capacitor in a capacitor coupling between phono and linestage.  Also, in a tube unit, no need for a cathode-follower at the output or and a solid state unit, no need for the analogous solid state topology.  As for separates, one advantage (to the manufacturers) is cost.  If you really want to spend money and pay for the same thing twice (chassis's and PSs), go for it.

I own both an Atma-sphere MP1 (albeit a fairly ancient one with some updates) and an Essential 3160.  Both of these units are fully balanced, inputs to output, and both have outboard PSs with separate supplies for the phono and linestages.  I can only imagine the sound of an up to date MP1, but it is somewhat restricted with only one pair of balanced phono inputs, designed for high gain but can be reconfigured for low gain.  For flexibility and amazing transparency, I would highly recommend the 3160 or the latest greatest iteration, the 3180, which I have not heard, in that both of these have entirely separate circuits for MM vs MC cartridges.  My 3160 has an exceptionally lucid linestage which was a hard sell to me, because I am at heart a tube guy.  I can only imagine how great the 3180 is going to be.

@lewm you bring up many very good points regarding SQ that should be considered when looking at full function vs. separate line and phono stages.  I went through several iterations of “separates“ before finally settling on a full function preamp for spinning records.  Why, because for the same dollars it just sounded better.  I have since decided, primarily because I’m old and lazy, to go with strictly a digital source. Particularity when considering the OP’s budget (if you have enough money in this hobby you can pretty much do anything) looking at a full function preamp like Vac or Atma-Sphere or I’m sure there are a couple of others that don’t come to mind, will give him the biggest bang for his bucks in his quest for SOTA.

If you want the best, isn’t it better to go with a line stage and outboard phono preamplifier?

@vonhelmholtz , @lewm beat me to the punch but the simple answer is 'no'.

When the phono section is built in the designer has better control of the impedances involved and certainly the interconnect- since that's been eliminated. You also reduce the possibility of ground loops, something that's always out there, in particular with single-ended stuff, grounding being what it is.

Phono cartridges are a balanced source, so if you really want to do things right the phono section will have a balanced input. One of the goals of balance line operation besides eliminating ground loops is to also eliminate interconnect cable artifact. If there's any place in the system to get that right, its between the tonearm and preamp, since any losses there cannot be corrected downstream regardless of how good your equipment is.

Ticks and pops are a common complaint that digiphiles often cite and for good reason. But most people are not aware that certain phono preamp issues can generate ticks and pops that sound for all the world as if they are on the surface of the LP. They are caused by high frequency overload of the input circuit. That might be a topic for another thread; I can explain more if anyone is interested- I've done that on this site a number of times in the past.  

This is an interesting subject - how to get maximum performance for $20k buying new preamp and phono stage. Just because integrating separates is more difficult doesn't mean that the result cannot be better. But maybe within this price level it would be at least not worse to get, as suggested, full function preamp from VAC, Atma-Sphere or CAT.  I am not sure what I myself would do.

All helpful discussion and suggestions so far. I agree (conceptually) that placing it all in one box has advantages, thus the question. I'll take a closer look at the units mentioned.