How should I upgrade? A new preamp with a phono stage or just a phono preamp?

New, Phono anything, I recommend finding sources that allow returns.

Have/try MC, use alternate cartridges?

No matter external or internal, I chose to get a separate SUT with some variations of impedance and 3 selectable inputs, thus only 1 cable sut to phono

Entre 100

https://www.ebay.com/itm/134511637279?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=b1b41ac6-d8b4-11ed-9474-333138643664

I chose this Fidelity Research FRT-4

https://www.ebay.com/itm/155407979749?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=3808290a-d8b5-11ed-9a31-326433663330

There are ones with dip switches, internal resistors ,,, they are more expensive generally, I’ve never owned/messed with one of those. My friend’s Melos Preamp had adjustable internals, I changed them for him until we got a preferred sound.

I try to avoid 'better' going for 'preferred' instead.

I had a vintage nikko nr 719 receiver with a built-in phono stage and a technics turntable and it played marvelously. Used with epicure linear speakers. Probably sounded better than most of the stuff out there in the modern age. Components were really built well back then.

There are several ways of looking at this and it all depends on what you like and where you see yourself going with the hobby.  Any good stand alone phono stage from any good company is going to outperform the built in phono stage of any integrated/preamp or receiver.  So if you buy a good stand alone phono stage now it would serve you well going forward no matter what upgrades you might consider in the future.  On the other hand, if you simply don't want the clutter, like the simplicity and elegance of a single piece, and there is nothing wrong with that, then go that way.

I have always been rewarded by incorporating the highest quality preamp and separate phonostage I could afford. Used Audio Research and Conrad Johnson tubed preamps and phonostage are among the best made. Going backwards in time and buying the best you can afford will award you with great, natural sound.

The Audible Illusions M3A is a fantastic unit. I owned one some years ago with the MM Phono stage. The lack of a remote control was the deal breaker at the time. The AI L3A/B has a remote yet no phono stage.

Chances are, you will not be disappointed in the M3A or B. For the money the M3A’s are going for, it is a steal!

Would recommend a separate Phono preamp. My experience with integrated Phono pre's is that's where they cut corners. Plus if you change cartridge or TT at some point you don't need to mess with your system's. pre amp. 

Good luck!

My $0.02 if you want a tube phono, go separate, unless you listen to vinyl all the time, you'll be putting hours on tubes for no reason. 

Also my 2 cents, the modulus is OLD and likely easily bettered. It wouldn't hurt to verify that input and output impedance between the two are actually compatible. Good luck 

We came across an old Conrad Johnson tube phono stage and even in stock form it sounds really good.  If you want the best sound you can from LP then you would be compromised to go with an all in one unit.  We repair and modify components and even the old Counterpoint preamps that we upgrade are not as good as the CJ as a stand alone unit.  The B&K is a basic good preamp but overall really nothing special.  Same goes for the AI which is typically hard on tubes and as a preamp is bettered by the Prima Luna tube preamp linestage.  

Happy Listening.

Mesch, why SS and not tube?

Tubes/tubes/tubes, my preference

I always recommend FEATURES, the vintage tube preamps have it all. (except remote)

Using my McIntosh mx110z as an example only because I know it best (although I had similar full features on prior McIntosh SS C28 preamp).

http://www.berners.ch/McIntosh/Downloads/MX110_own.pdf

no MC input, but two switchable MM phono inputs which is handy. 

Has your needed tape loop; many inputs; trim controls to match volume of inputs when changing sources; Balance; tone; filters; loudness for very low level listening; and importantly the MODE switch.

Other makers, models exist with full features. This vintage stuff is what they made their reputations with!

I bought mine, then sent it to Audio Classics for test/replace parts matching existing (i.e. not 'upgrades', keep original). Best thing they did was put new gold plated rca jacks, the old ones were corroded, and they were slightly undersized.

Came back totally quiet, I couldn't be happier.

I paid around $1,100. and another $1,100 to Audio Classics (early 2019, prices for everything way up since then).

I get remote volume from my Cayin tube amp. I used to have remote balance, I think I will put my Chase RLC-1 back in play, perhaps only use it via tape loop. I have R2R, but only use mx110z Play IN (Tape monitor)

https://www.bonanza.com/booths/lbodin/items/1424839694?awc=6238_1681059762_53d236aa55c29a3c9c05558ec55fa1f7&utm_source=awin&utm_medium=cpa

It has two sets of identical outputs, how are you switching to speakers a to b now?

MUST have remote for RLC-1, no face controls, a door stop without the remote.

If. Your tube pre and amp make for a good pairing for you I would purchase a quality SS phonostage. 

The Audible Illusions has 2 volume controls and no balance control. One for the left channel, one for the right. While it has received great reviews for sound, it might be inconvenient for some to use verses a preamp with a single volume control & a balance control. You will be adjusting the balance every time you adjust the volume. For a similar preamp, I suggest a MFA Magus C, a bit old but excellent sound. 

Dill

What do you mean by dual volume controls? I deal with that as it is. I’m looking for the best upgrade for the money. I’ve heard that the AI modulus 3a pairs very nicely with the Mccormack DNA

I'm using a Technics SL-1600 with a shure M95ED. I'm sure I will upgrade the cartridge at some point but that's a whole other can of worms.

What table, arm and most importantly cartridge are you using?

I would get a phono stage and get rid of the B&K. The Audible Illusions Modulus 3a is a good preamp, however the dual volume controls are inconvenient. Look for a Jolida JD9 MKII for a nice unit at a good price. Your power amp is excellent.

I should say that the B&K has a direct bypass button that I use unless I'm listening to vinyl. My sources are connected to the B&K inputs and the B&K is then run through the Bottlehead and then into the Mccormack