Audio Research LS-7 LS7 upgrades suggestions

Hello all,

I just acquired an Audio Research LS-7 and would like to make relatively simple upgrades to take it to another level. I have searched online but found very little information, so any and all suggestions are very appreciated.

The easiest path is to install some NOS CCa's or, at least 7308/E188CC tubes. Depending on your taste in presentation, you might try Siemens/Telefunken(very transparent and extended in both directions, w/o bloat or glare), Mullard/Brimar(warm, "tubey", British flavor) or Amperex Holland/Valvo/Phillips(middle of the road, and beautiful, especially the "pinched waist"). All will provide better imaging and sound stage depth than anything currently manufactured. Replace the fuse with a Hi-fi Tuning piece. Major improvements in overall presentation and dynamics can be had by installing an IEC inlet(Furutech and Oyaide make some nice ones), and upgraded powercord(ie: Synergistic Research X2 AC Master Coupler). Another step providing more natural sound overall would be to replace the rectifier diodes with CREE Schottkys, HEXFREDs, or soft recovery FREDs from IXYS. Perform the steps individually, so you can appreciate the impact each has on the sound of your system.
Rodman is right on. Replacing RCA jacks may help too.
Get some estimates first. I suspect that it may pay to sell this and buy an already updated unit. From what I know, some of the other models are better? 6C or 8's?

You may end up spending $700 and never be able to get it back out of the unit. However, it is still a really nice piece.
Replace the Rel-cap coupling capacitors (the yellow ones).
Thank you all for the responses.
I think tube rolling, Hexfred diodes and new in/output caps will make a very nice upgrade. But the limiting factor in the LS7 is the power transformer which is rather small.
I had the LS7 but moved up to the LS22, the transformer is twice the size of the LS7 and the LS22 is also a balanced circuit which means double of most componets.
-Caps - 30% increase or just different but not better
-Diodes - 30% increase
-Fuse - 10% increase
-Damping chassis etc... 2 -5% increase
-New footers - 2 -5% increase
-Power cable - 5 - 10% increase
-Replacing Potentiometer with like a TKD or better than the basic Alps or nobel whatever it is in the unit can be a - 15% increase
-RCA's - depending on Resistance, if you go with a new gen WBT or something maybe a 2 - 5% increase

All this depends on how that unit reacts with the selection of new parts vs. another unit. Also how easy this unit is to work on, and how many values you can see or figure out on the parts to actually replace them.

Some are more effective in certain flavors, some are not. Tubes are easy, try them, but that's gonna cost you as much or worse drive you crazy buying NOS and not finding a happy spot!
Thank you all for the great suggestions. So far, it appears that the two simplest upgrades I should do now are the diodes and fuse (???).

Elevick has an excellent point about chasing too much money after mod's etc on a modest, 'budget'(for ARC), preamp.

Apart from posting how much money you are willing to commit so you can get some more specific guidance, you might like to tell folks what you mean by 'taking the unit to the next level'. Some things are do-able, some things are not, some things are cheap, some things not. It helps if you can critique your LS7 and pin down exactly what you would like to improve.
Don't know if Diodes would be simplest, that is a pretty tedious and small component in the power supply to remove depending on how good you are with soldering and cleaning the board etc... I am not familiar with how difficult it will be in your unit specifically depending on the layout.

Fuse should be easy, anything else beyond that or Tubes that just plug in like the power cord, unless its a hard wire not an IEC will take an experienced Tech. or really good DIY solder guy.

Good luck
I don't want to spend more than about $300 - $500 for the upgrades. Because the LS7 is a "budget" component in the ARC product lines, I thought that perhaps I can replace some of the "budget" parts and improve the sound. But I don't want to go crazy and spend 10X more than what I paid for the LS7 (I bought the LS7 for $300). My skillset is limit to soldering only, so beyond that, I will probably won't attempt.

Newbee, the LS7 is still being shipped to me, so I don't know how it sounds yet.

Thanks for all the suggestions b/c I am sure other LS7 owners might want to do the same upgrades.
For 300 to 400 you can jam some nice caps in the critical spots and do some diodes, with fuse, new power cable, very easily… Probably can do it well under 200 if you are able to do it pretty easily yourself for sure, somebody might mod it for you with shipping for around 300 as well. I can tell you I had a LS7 I believe which was the tube based hybrid? And I had a LS3. The 7 was nice, I remember it being a little dry, maybe a bit thin depending on the amp and speaker match you run…

Definitely you could get better midrange bloom and BAss down low with some higher grade caps, I suggest the new Clarity ESA range which are very dynamic and warm, far better prices and sound over the big mundorfs etc…Clarity MR range could be even better, but very expensive, and get much larger in size. If you can make them fit, but remember they become far larger when you go to exotic caps over most manufacture stock sizes at an equal value. Jantzen Superior caps are great as well for very little money, better than the Relcaps, MIT, cardas, mundorf ranges for sure at the price levels.

That unit should have a ton of room in the AR chassis and I think its capacitor configuration is pretty simple and not many of them. If you want the most bang for the buck and can do it with a little good soldering that’s where I would start for the most effective mod, all the rest will fall behind for fun.         
Just for the general info pool: The four rectifier diodes are right next to the transformer and would take all of 20 minutes(if one were really challenged as far as dexterity) to change out, at a cost of less than $16.00(if IXYS soft recovery FREDs were used). An upgraded power cable should be considered a "must", regardless of what preamp is discussed(figure around $200.00), unless the unit comes with one. YES- The coupling caps(especially) will make a dramatic difference in sound, but finding the ones that suit one's tastes can be harder(and less predictable in the unit/system) than rolling NOS tubes. There again NOS tubes should be considered a "must"(if maximum musical enjoyment is the goal), regardless of the gear discussed. AND the ones you don't like can be sold at just slightly less than what you've paid(you'll know if they're keepers in the first 10hrs, which won't affect their measurements in the least). IOW: Most of what he would spend on his LS-7, would be spent on any other tubed unit he might purchase, in the effort to obtain enhanced music reproduction.