What to add or change for my system?

This is my first post, so please have pity on me if I break any rules.... :)

I immersed myself in this hobby a few years ago, and I'm completely hooked.  And best of all, my wife is.....almost hooked.  I initially purchased speakers from Axiom, OPPO 103D from OPPO, and Parasound preamp and amp from a local dealer.  These were connected with Kimber Timbre cables.  I also have a Furman Elite power conditioner.

All of that changed in December.  My system now consists of:
  • Martin Logan Summit X speakers; purcahsed new on AG
  • Plinius Hautonga integrated amp; purcahsed on AG
  • Oppo 105 that has been modded by Tweak Audio for even better audio; purchased on AG
  • Bryston BDP-1; purcahsed on AG
  • Gustard X20 DAC that has been modded by Tweak Audio; purcahsed on AG
  • Gustard U12 USB interface; purchsed new on Amazon
  • Clear Day silver speaker cables; direct from Paul, a wonderful person!
  • Avanti Audio interconnects; direct from Avanti
  • Furman Elite power conditioner; Audioadvisor

As luck would have it, I just got a nice bonus and feel the itch to add to, or make better my system.  Not knowing what to consider, I'm hopeful to get some suggestions from you.  If this was your system, and you had $3-4 thousand to spend, what you add or replace?

Thanks for your thoughts!!!
1. speaker placement/listening chair placement
2. room treatments
2. upgraded source material
Looks like you made a huge leap the first time you upgraded . Looks to me the changing of amps/integrated would reap the most significant sound change . What are you looking to improve upon or change ?
As Randy stated room treatments Can be a big sound change too
Do you have your speakers plugged into the Furman ? The stats i've owned have responded well with plugging them into a conditioner or Furutech  receptacles
I was in Japan a few months back and went to Akihabra for a day.  It's a section of Tokyo that is packed with audio stores.  It's amazing!  While there I did purcahse two receptacles, but I don't remember the make.  The power conditioner and the speakers are plugged into these.  

I was thinking the integrated might be a change, but it does sound nice.  The Plinius puts 280 watts into 4 ohms.  Just not sure what additional power will get me (noob).  I listen mostly to jazz and some 70's rock.  Also don't listen at very high volume.

Would the room treatments go behind the speakers? 
Power numbers are not what you should strive for . No telling what you will get by going with more power . Just know you will get a change in sound by changing the Plinius is all .
What is it you think could be improved upon is the question you need to answer .At some point you will feed the Martil Logans with gear that cannot be improved upon . You may be there right now for all we know .
If it sounds good, why tempt fate? 
If not, then tell us what you are lacking or think you are lacking?
"would the room treatments go behind the speakers"
 In a word, yes and just about everywhere else for optimum results.
Go to GIK acoustics and ASC for great set up guidance. 
IMO you will get the most bang for your buck with this upgrade.
@smills59 You've only been listening to the current system for 2 - 2 1/2 months.  Put the money in the bank (for now) and give yourself some time to get used to the change.  If something is wrong, it will eventually rise to the surface.  Bring that back to the group and let us hash that out.  If you're lucky it will still sound wonderful and you can spend it on music.
Thanks djohnson54, sounds like good advice.  The one thing I will do is take a look at room treatment.  With the ML being dipole, I do think I'll get some improvement.  I had not even considered that.

I will get these ordered and then report back.  I promise!

Thanks everyone!  You guys are great!
I'll vote with djohnson54...kick back for awhile and get used to your system.  Play Everything you've got at least 2~3X, esp. the selections you're well-acquainted with.  Fool around with speaker placement...see if anything stands out as an issue.  Do some simple room treatments if that seems likely.

Just because you've got 'the itch' doesn't mean you've got to scratch it. ;)
Besides, you can have the luxury of shopping about at your leisure for the 'next great thing'.  Enjoy....*G*
Other posters have already said it, but to add some weight to their words, three worthwhile considerations are room treatments, isolation feet (vibrapods and support cones worked wonders for me), and a Hubbell cryo'd receptacle all made remarkable differences in the fine tuning of my setup. 

With room treatments, it can be easy to spot what's add if a friend can help. All they have to do is hold a fuzzy fleece blanket in different parts of the room while you listen. You should be able to pinpoint which areas are reflecting sound the most and add treatment there. 

What are the dimensions of the room in question? How far apart are the speakers, and how far are you from them?
Welcome! smills59-

kick back and enjoy the music and your system for awhile. There is plenty of time to change out gear.  Before you do, consider, auditioning cabling (most important).

Happy Listening!
Do you have dedicated AC breakers and lines, going to your system/listening room’s outlets? I wasn’t so much surprised, as I was delighted, when I installed a couple runs of 10 AWG Romex(twisted together) to mine. And YES: room treatments/cabling!
smills59, I agree with many others here that the room has the greatest and most underappreciated effect on the sound you get from your system.  That said, many of us don't have a dedicated room so room decor (otherwise known as WAF!) plays a part too.  It sounds like you are blessed with a tolerant wife (I am too - up to a point) so you are lucky.  Search the forums for some low cost/free things you can do in your room (wall hangings, area rugs, plants, etc.) and experiment before spend big bucks on room treatments.
Agree with the others. If you feel satisfied at this time, enjoy it. One important thing to attend to if you haven't already is a good rack to put everything on. It does make a difference. I recommend Adona for sonics and adjustability.
be careful not to overdo the room treatment...
Power cords and sub (s)
Even more great suggestions!

I do have vibration pods for every component.  Also have Pangea power cords for every component going to the Furman, and a massive cord from the Furman to the audio receptacles.  I don't have a dedicated line from breaker box to wall, but that isn't really possible in my case.

I made cable risers from Styrofoam squares that I painted black and put a felt pad on the bottom to protect the wood floor.  Cables rest on top.

The room is not dedicated to audio, it's our living room.  It's 15x16 with one of the 15 foot sides open to our dinning room, other side is a fireplace.  Ceiling is 8 feet, sloping both sides to 12 feet in center. Speakers are 8 feet apart, 3.5 feet from the front wall, and 4 feet from the side walls.  It's a pretty big room.

I do have a decent music collection all on hard disk, and I listen to Tidal a lot.

I like the idea of room treatment.  Because the MLs are dipole, would a 2x4 absorption panel directly behind the speakers work best?

Thanks guys!!!

Does your system benefit from the cable riser?...mine doesn't
Stringreen, I'm not sure. But the risers were only about $20 to make and took only the time for paint to dry. I bought the styrofoam blocks from Michael's for $3 each, then a can of spray paint and felt pads from Lowe's. They look nice enough, and importantly really help eliminate dust bunnies.

Not to start a heated debate, but what about changing the fuses in the Plinius?  Pretty easy as all fuses are accessible from the back of the unit.  I've read pros and cons on this, as I'm sure all of you have too?

You should check out the thread on the Synergistic Research quantum black fuses. They seem to get tons of raves. 
You have a very nice system and the next upgrade is going to be expensive. Separate components with mono-block amps is the next level and if it was me the mono-blocks would be tube amps. Keep the integraded amp in case you need a spare when equipment goes out of service. The next level will provide significant improvements. 

Thanks russ69, that's what I was afraid of. :)

I did add Synergistic research Black fuses to the Plinius integrated.  My daughter is staying with us and she is my help to make sure I'm not hearing improvement when it's not really there.  She has no dog in the hunt.  She's been listening to my system with me for about two months now.  She helped with the Clear day speaker cables.  As soon as I turned on the Plinius with new fuses, she looked at me and said "WOW!"  I heard the difference too, but usually doubt myself.  She is also very sure there is a significant difference.  I feel the money for the fuses was very well spent.  

Bryston told me not to bother upgrading the fuse in the BDP-1 because there are no fuses in the signal path, and the fuse in the OPPO is soldered to the board.  The DAC has no fuse, so I guess I'm done until I get the urge for those mono-blocks.

Thanks everyone!!!

Jumping in here. Like others have said, you have some excellent equipment selected here. Since you are fairly new to this game, I would also suggest (like others) to listen to this system for several months and get used to the sound. I’ve been in this game for about 17 years and sometimes I can immediately determine when something isn’t working, but sometimes it may still take me a couple months to realize something is wrong or there is some characteristic of my system that is bothering me. That being said, I would suggest making tweaks to your system instead of doing major upgrades. Some tweaks can actually make significant impacts to your system.

Speaker cable risers - I’m not entirely convinced that speaker cable risers really work....but, if you want speaker cable risers, I would think that Styrofoam is not a good material to use. Styrofoam can be susceptible to static electricity and cause magnetic fields. It would be better to use a non-magnetic material (such as wood) to build your speaker cable risers. I’m sure you could fabricate some cheap risers made from wood components (even just tying a few wood sticks together with string as a riser).

Interconnects - I see that you switched to Avanti Audio interconnects, which use a 26awg conductor. While there is much controversy in the industry as to the best awg for an interconnect, I have found that smaller wire gauges will give a more closed-in sound. I have tested this (using an Vovox 26awg solid-core audiophile interconnect). What happens is that there is somewhat higher resistance with smaller gauges. I have found that larger gauges will let the music out (in a sense larger awg will allow the music to "breath"). More powerful bass. Instruments hit with more authority. Your previous interconnect (Kimber Timbre) uses a varistrand setup that has a much larger 19awg conductor. If you still have these, I would suggest putting them in and see how they sound. Because you have such a strong solid-state system, I would stay with copper here.

Speaker Wire - I have use silver cable in the past. It has its own sonic signature. Some people love it, some don’t. I have evolved to where it is not my personal taste. Silver is fast and will tend to push the upper mids/highs. Bass can be light/weak. Silver can be good when paired with slow/warm equipment like tube or McIntosh (definitely not Plinious). Once again, this is all personal taste and I recommend you listen for a several months before making a decision on silver.

Burn in - both equipment and cables require some amount of burn-in before sounding good. Usually, the recommended time is around 100 hours of constant use. Some elements (such as rhodium plating and some types of electrolytic capacitors) require 200+ hours. I know for a fact that the Oppo 105 needs well over 200-250 hours of burn in before it settles down and sounds best.

Fuses - the choice of fuse can drastically change the sonics in your system (believe it or not). There are so many different opinions here. Personally, I found Furutech Rhodium to be the absolutely best (but burn in for 200+ hours!). I will say that rhodium plated elements are very transparent and revealing, so much that it could reveal problems in other areas of the system and you may end up replacing all fuses/connectors with rhodium plated Furutech (like I did). However, the end result is absolutely outstanding. A much more forgiving fuse is Isoclean, but some may find it too warm sounding. Hi-Fi Tuning Supreme are silver and are fast/detailed, but push mids/highs in a way that’s artificial (in my opinion). Synergistic SR20 is very fast and clean, but it was so clean that I lost emotional connection with the music. Synergistic RED is the least offensive fuse I have found. The RED will sound okay in any system, but not extraordinary. I found the resolution lacking, but it didn’t sound bad. I have not tested SR BLACK. The cost for me too much to try this over the Furutech.

Power cords - I can go on a very long discussion on this subject because I have spent a LOT of R&D in the last couple years on this, but I think you have enough to work with for now.

Finally, if you do make a change in your system, please make sure you burn in the device (if it is new). Then listen to it for several week (or a couple months) to get an idea of what you are hearing. Then make a decision on whether or not you are keeping it.

oh, forgot

Room treatment - be very careful about acoustic treatments. It can be really easy to over-damp a room and then the sound becomes dead. If you have hard-wood floors, then put as much broadband acoustic panels up as you can (in corners especially). Contact GIK for advice. Their panels are excellent for the price.

If you have a fully carpeted floor and/or plush furniture, be very careful on how many broadband panels you put up. I would almost suggest using membrane type panels, like the GIK FlexRange Limiter. Alternatively, use Owens Corning 703 FRK panels. The "FRK" panels have a foil front that does much the same as membrane -- it mostly reflect mids/highs instead of absorbing them and keeps the room live and exciting sounding.

Just re-read this thread.  I see that you got SR BLACK fuses.  One of these days, I will probably have try one, but my testing with rhodium plating and Furutech components has been so successful, it may be hard for me to change.  Though, like I said, rhodium is a double-edged sword.

For the Oppo, google for the "oppomod" website and go buy a linear power supply for the 105.  It's a bolt-in replacement (no soldering necessary).  And you can easily upgrade the fuse in this linear power supply.  Even if you are just using the Oppo as a digital transport, a better power supply for the digital section is still a benefit.

Expand your source to include either a great table/cart/ and phono section or a Reel to Reel.

That will keep you busy, engaged, happy and frustrated for many moons to come.
auxinput, I still really like the SR Black fuses, but I confess these are the only ones I've tried so have no comparison.  You are right, they are expensive.  I had to get five of them!  :(   I like your comments on the silver cables versus others.  Perhaps that's a good next step for me.  Any suggestion given the gear I have now?  

raymonda, I know, I keep looking at turntables on Audiogon and  also magazines I get, but so far have resisted the temptation.  As much as I love the musical side of this hobby, and I do, I also love the technical side.  The gear, the cables, etc. fascinate me.  I want to try them all, but alas, money and family are a good limiting factor for me.

Thanks again everyone!

For speaker wire, if you want to wet your feet very cheaply, I always suggest getting some basic 12awg stranded OFC copper speaker wire from Monoprice (or any other source). At $15 for 50 feet, it’s such a cheap way to see how copper works in your system. Honestly, they aren’t that bad.

If you are okay with a DIY approach, you could get some Neotech NES-3002 speaker wire from VH Audio and cut/strip the individual solid-core strands and mount them in Furutech FP-201 (gold or rhodium) spades. It’s not difficult, but just takes a little time on your part. This speaker wire is on my list to try (I’m currently just using the 12awg stranded).

If you want to get a manufactured speaker cable, the Wire World Equinox 7 comes to mind, or the Wire World Eclipse 7 (if you’re willing to spend the money).

I don’t know about other speaker cables, but one thing I make sure to look for is OCC Copper and solid-core conductors. You could look at Kimber 8TC, which is a good cable. Kimber is not OCC, but close. It’s also not solid-core, but the varistrands only have 7 strands in each bundle.

For interconnects, I have tried the Wire World Eclipse 7. It is a very good copper interconnect. I would say it’s somewhat on the soft / laid back side, but everything is there. I hand-make all my own cables and I haven’t found a manufactured cable that can compete.

I do have a set of Audio Sensibility XLR cables up for sale on audiogon, but again they are solid-core silver. They use three OCC solid-core conductors per signal leg (20 / 22/ 24 awg). This makes for a 17awg cable, which is significantly larger than your 26awg. It is a very fast and clear cable, revealing very minute details in the music. It’s about the best silver cable I have heard, but again it is silver. It will translate waveforms to be a higher frequency than they should be. This is excellent for sources/equipment that have a very slow slew rate and are very warm.