Should I upgrade my preamp?

Wrong! The biggest upgrade would be to get better speakers/phono cartridges. These are transducers. They convert one form of energy to another form. Audio electronics have been a solved problem for decades. 

Drive a bit further into Michigan ( i’m a Buckeye…so i know how that might hurt )… Seek out Paragon or even visit Indy. Not sure what is left standing in Columbus. Your current ARC preamp is very romantic sounding vs the unit you mention… obviously you have a lovely sounding system… the cartridge in particular… first order speakers from Jim T. Fun. i advise at least an LS-17 with a vpi magic brick on the transformer.

Have fun

I would 1st want to know from your words, specifically, what sq are you missing from your system ?, and / or what sq are you trying to add to your system ?, and / or, you just got the upgrade bug ? There are many things we can do to enhance our systems. Room acoustics, speaker listener positions, cables, isolators, etc. Have you optimized any of this, or are you restricted in any way to optimize any of this ( not having a dedicated room, as an example ) ? The Denon piece, btw, is either the DCD1500, or the DVD 1500. My best, and of course as tomic says, have fun. MrD.

+1 @mrdecibel Totally depends on what improvements and sound characteristics you’re looking for. I’ll just caution that with your amp and speakers you should be careful to not venture too far into greater neutrality/treble detail or things might get too bright. The newer ARC preamps will likely skew this way relative to what you have now, which is why it’s so important to share what specifically you’re looking for sonically. Just my $0.02 FWIW, and best of luck.

I am not of the camp that you must understand what is missing from your current system. When you perform a significant upgrade with high quality components, you find out what you were missing. When you are talking about components like ARC you can be certain of great results. The upgrade to an LS28 would be a great upgrade. I completely agree that the preamp is the heart snd soul and this is a great preamp. In addition it sets you up to hear marked improvements when you choose to upgrade any other of your components.

I have owned many versions of ARC preamps and phono stages. They are wonderful. They only stumbled a bit on the REF 1 and REF 2 preamps.

I have owned many ARC preamps including the LS2B, but not the MK2. I also feel the preamp is the heart of the system. Much more important than the amp. I currently own a Ref 5se which I dearly love. My Ref 5se was a demo. Buying a demo or even used can save quite a bit of money. And it is already broken in. The LS28 is a wonderful preamp and would be a significant upgrade. Get the se version if at all possible. Speakers would also make a big difference. 

My advice is to make a long term plan and work toward it. Upgrade one piece at a time. Maybe a preamp first and then speakers. You may not realize the full potential  of the new preamp at first. But as you upgrade other pieces you will. And you will not feel the need to upgrade it for a long time.

tomic601 Yes, I’ve been checking with Ann Arbor for several months now.

mrdecibel you are correct, it is DCD-1500, typo on my part. If I remember correctly, I bought this player in 1986. I’ve tried other CD players over the years and they either lacked in bass or the highs were to bright or tinny sounding and in some cases less detail. My system’s sound stage is not mid-hall depth, it’s more like the 10^th row and very engaging. The preamp is 30 years old and to my ears it has lost some of its magic. So, is time to replace or recap or maybe look for a new CD/SACD player?

I forgot to mention speaker cables and interconnects are all Transparent Music Link Supers.

We moved a few years ago and my listening area is not good, my sound stage is very compressed now. 

Soix I grew up listening to tubes. When I was little, I remember watching my father build his first stereo preamp from a Dynaco kit. So, with ARC’s newer equipment moving away from the house sound that embraced tubes to something more neutral, with just a hint of tube sound. I hear your warning and it is my primary concern.

@ghdprentice ,1st, I would like to say I read the majority of your posts and enjoy your sentiment and opinions. However, you and I are very different listeners...and this is ok. I spent most of my life helping others build / upgrade their systems. You say you do not believe you must understand what your system is missing. Maybe the word understand is not the correct word. My experience shows the listener simply wants more out of their system, before the upgrade comes. This is the reason for the upgrade in the 1st place. To take a system, and simply exchange a new component for the sake of it, is not how I see it. A listener needs to know what his / her priorities are, with music and sound, in building a system, and I tried to help / teach this to the client. The 1st and foremost step in helping someone with their system build / upgrade, is to determine what sound / presentation do they want, to learn what their listening habits are, the music listened to, and of course, the environment they are in. I know you love AR tube gear, and SF speakers, and I understand why. This presentation might be fine for you, but not everyone. Admittedly, not my cup of tea, as I believe you might feel the same concerning my system. Why, because we both value certain aspects of recorded music reproduction. So, what is good for you, or me, is likely different than the next person. Most listeners I correspond with, are still so lost in achieving their holy grail. They have not figured out what they want...or know what is potentially available. A problem that exists ime, is that listeners do not know the difference between the reproduction of recorded music and live, unamplified music, and try to achieve that balance of both. I apologize for going on and on, but recommending anything to a listener who wants to upgrade, I need this information to help them further. Before I retired, I did have many happy clients, because I concentrated on what "their" likes, wants and desires were, and helped them get to that point by educating them to the best of my ability. Anyway, I hope this did not turn you sour in any way. Remember, ymmv, we are all different, and music listening should be fun. Listeners, mostly audiophiles, experience neurosis with this hobby, which is why I retired. Unfortunately, it is getting worse, imo, likely because of the world we live in. To the OP, good luck. Again, I apologize. My best, MrD.

@mrdecibel 

My experience with high end audio has been that each significant upgrade I have made of high end main stream audio components has resulted in a great improvement on my system. I agree that it is very helpful to know what sonic characteristics you value. But, you need an experience base to really understand what the choices are. In the case of a preamp and what we know about the poster, I think the ARC is a very safe bet for this person. Now if it was speakers or an amp, much more information would be required. 
 

I agree that we have different values… and that is fine. 

I think your speakers and phono cartridge are fine. The weakest link in my opinion is your cd player. The old ARC preamp has more potential and if you add a DAC and a good transport you can improve the performance of your system tremendously. 
In example Audiolab 6000CDT transport under $400 used and a Chord Qutest DAC around $1000. Or a PS Audio Directstream DAC going under $1800 now on TMR as a special. You can upgrade the preamp later. 
The LS 28 with your Denon cd player will be garbage in garbage out type of deal. 

I thought the 3.6 was the best per dollar speaker ever produced by Thiel. I liked them when driven by Krell and Levinson, which were available to me back then. Such an improvement over the 3.5. When Robert Harley reviewed the 3.6 speakers in '93, the LS2B was used throughout the review. He never stated it was a weakness in the system. You might want to consider having the LS2B serviced / updated. You still have not told us what sq you are looking to improve / change. The source is always an area to upgrade, as I agree with audphile1. I would also try different cables, if yours have those time alignment [email protected] good my comrade. Enjoy ! MrD.