Phono preamp for a Denon 103R cartridge.

I recommend you look at the Lounge Audio LCR series of phono preamplifiers.  There are three models, ranging in price from $420 (LCR III) basic model, to $610 (Silver), to $870 (Gold).  I am not familiar with your cartridge, but if it is a MC you will need a step-up transformer, which Lounge Audio has for $440 (standard model) or $595 (Silver Wire model).  I purchased the Gold model to use with my Thorens TD 126 MKII turntable and Audio-Technica MM cartridge, and I was simply stunned by the quality of reproduction, so much so that I am beginning to look at purchasing more vinyl discs.  TheLounge phono preamplifier does a wonderful job of reproducing music that sounds so much more .... .... "organic and alive" than many of my digital recordings.  Finally, they are hand-made right here in the US, in the Los Angeles area; I talked several times with Robert Morin, the founder of Lounge Audio and the man who, along with family members, crafts each unit.  Is it "the best thing out there?"  Probably not, but at the price it yields a superb performance.

Zarf

I have used 103Rs (4 in all) for many years.

During that time I also upgraded to my Phono Preamp to a Zesto Andros 1.2.  It is a very flexible Pre (lots of Ohm settings, even separate L/R grounds) and sounded great with the 103Rs.  

It uses 4 12Ax7 tubes (2 per channel and inexpensive to replace) and to my ear, it out performs SS options. 

Because it is an older model, second-hand units are quite inexpensive on AG and elsewhere.

Lastly, the Owner/Designer, George, still answers the phone himself (I called him to chat about tube rolling).

Good luck,

P.S. I am an end-user and not affiliated with the audio industry

I got a good deal on a Sutherland KC Vibe, and I was blown away at the sound quality I heard for under $700.  I can say the same for the Schiit Mani 2.  I gave my son a Rega P3 I wasn't using to see if they would get into vinyl, and needed an inexpensive phono amp.  I bought the Mani based on my prior experience with Schiit Audio products. Incredible performance for the price.

There's no need to take out a second mortgage to achieve quality sound.  I just laugh when I see people on here debating on gear that cost as much as my pick up truck, bass boat and trailer.  Believe me, the truck, boat, and trailer will get used a lot more and will have much greater resell value.  I love my music and my 60+ year vinyl collection -- but my vintage system sounds fine.

I own a 103R and really liked it with the E.A.T. E-Glo Petit. It has plenty of gain, gives you the ability to roll the 12AX7s, front (actually top) panel controls for easy loading changes, and really quiet.

I've owned a number of under $500 solid state phono preamps, and while they were all competent there was a very audible difference as I moved up the chain.

Have you looked into a Denon AU-103?