Analog system, upgrade preamp

Thanks for the prompt responses, had not set a budget but trying to probably stay under 10k for amp/preamp.  Recorded quite a bit back in the day that I recently started listening to again.  We use to swap vinyl so have a lot of cassettes. I  have Revox B77, Revox B215 cassette deck, (keeping), and some DBX equipment.  The speakers are La Scala and JBL 4312s.  Thought that the foundation would be the Amp/Preamp to upgrade to a softer less edgy sound. Did not know about wire upgrades,  still using old Monster wiring from over 30 years ago.  
Not going for surround sound tried a 5.1 and did not like the results. Hoping to upgrade amp/preamp and keep all old playback including Dual CS 721 with Shure V15V.

Paramount is I do not want to continue wasting time or money trying to figure out if a particular piece will do what I want.  Been at this for about 6 months now and not making any progress. 
Thanks

Thought that the foundation would be the Amp/Preamp to upgrade to a softer less edgy sound. Did not know about wire upgrades, still using old Monster wiring from over 30 years ago.

 
Good to hear your speakers are nice and efficient. You do not need a lot of power, just good power. Short and sweet: Raven Blackhawk https://www.ravenaudio.com/product/blackhawk-mk3/ Do not be put off by the price, search the comments, read the reviews, this will sound a lot better than any separates you will find for under $10k.   

For speaker cables if you are under 10ft then it is definitely worth looking for quality. Lots of good used cables out there 6ft, 8ft length. Synergistic Research has made so many great cables over so many years you simply search and find whatever you can afford, do not worry, it will be so much better than Monster your jaw will drop. Then do the same for your interconnect. 

So you spent $4k on the amp, $2k on wire, and already I guarantee better sound than you can imagine. You keep the turntable, fine. Put it on a Townshend Pods https://www.audiogon.com/listings/lisa9dje-townshend-audio-seismic-isolation-pods-set-of-4-sizes-a-b... Or a Platform. I use Pods under my turntable. But it depends on the situation. Your Dual might work better on a Platform. Either way, point is, these things isolate the turntable so well it improves the sound to a degree you will find hard to believe. 

This will probably leave you with just enough to upgrade your phono stage. Your Shure cartridge, if it is MM and 3.0mV like I think, then you can use the Decware ZP3 phono stage https://www.decware.com/newsite/ZP3.htm and you won't need a step up transformer.   

If you need to save some money the Nighthawk is $1k less and you can always buy cheaper wire. But the main thing to get across, with a Raven amp, Decware phono stage, and your turntable on Townshend, the rest of the stuff you have will sound so much better you will not believe.  

Check it out. Read the comments and reviews. These are all small companies that the only way they survive is by making really good stuff and selling direct to the customer. Very, very hard to beat. Certainly not without spending a lot more. 

Oh, forgot to mention, since you use tape- the Decware ZP3 has a neat feature where it can be used to replace the EQ on the tape deck. This does call for a simple mod to pull the signal directly off the tape heads and into the ZP3 via interconnects running directly between the heads and the phono stage. Read up, there is some info on their site. This one feature alone makes this totally the phono stage for you!

SIMPLY BLOWN AWAY!!! Thank you for every recommendation made i am starting my search immediately.  This is exactly what I needed was someone to lay it out for me because I've grown weary with research and trial and error. Forever grateful
C