What value for these Infinite Slope 1.8 speakers?

Three years ago I purchased a beautiful set of Infinite Slope 1.8 speakers and they sounded fantastic. Upon doing some research into the speakers I discovered that one of the designers, John Sollecito of John Sollecito Engineering lived in Connecticut, not far from my home town of Guilford, CT. I called John and spoke with him about the speakers and he had nothing but positive things to say, perhaps as one might suspect but still, these speakers were obviously something pretty nice. I made arrangements with John to bring the speakers in for evaluation and after a lot of discussion, even though he was quick to say that they needed very little work, I decided to have all of the drivers and the crossovers replaced and brought up to 2011 specs. John did the work himself and the speakers ended up sounding far better than I had imagined they might. But these days I am in a downsizing mode and am considering selling these speakers. When John finished the job he stated that if he were to design and sell these speakers today in the configuration that they are currently in, he would charge a minimum of $5500 per pair.

So my question to this forum is about setting a fair market price for these speakers. Would anyone care to chime in on this? I sure could use some constructive help with setting a price that reflects the actual quality of the sound, the beauty of the build and the rareness of the speakers pair in an updated configuration. Thank you ~ Frank Blackwell
That is a tough call. I believe his assessment of what the price would be if they were made today, but they are a very old concept comparitively, and the person who might be interested might also want them in original condition, not upgraded, desireable as that may be. All you can do is set an opening auction price that is the lowest you would accept, and let the market dictate their value.
Tampering with classics is risky. I have a McIntosh 2105 that I put non-original capacitors in, as well as modern binding posts and input jacks, and an IEC outlet. I am 100% sure that I have destroyed its resale value, because that buyer wants all-original, or factory replaced parts. I knew that, but my intention was not to sell.
I see what you're saying but these are all original factory parts in-as-much-as they are exact replicates of what was originally used but are the corresponding parts as built today. And the person who selected them and did the install is the original designer. But maybe what you are saying has weight with more people than I imagine. I'm hoping to get $2800 for the pair so that is what I may start the bidding at but I will wait to see what others say. Thank you for your comment Roxy. ~ Frank
Hi Frank,
I understand what you are saying, and a lot of times with things like this, it's a question of being lucky enough to find the right buyer who happens to want those particular speakers. The other problem is that there are so many other late model speakers that are in virtually new condition for sale on this site that are going for 50-70% of their original list price.
I'd be happy to get 25% of the original price, but would not bet on it. Not made anymore, not supported, could go to 20%, 15%.......

Only true classics are worth putting money into: old Quads, JBL, Tannoy,, other than that old speakers are old news and value is low. How they sound is absolutely immaterial unless you get that rare impulsive guy who stops by and falls in love with the sound. That's a low probability situation.
They (IS & Source) are excellent speakers. John made me a pair of carbon fibre 3 ways 10 years ago using only the finest parts. My cost was $1,000.00 pr. and they were valued at $3,000.00 pr. When it was time to move on I took $400.00 for them. It's got a lot to do with luck and timing. Shipping is a whole different can of worms. The other fellow was right in that only well known original classics will sell for top dollar. Sure, you'll take a hit on these but shop carefully. There is always somebody else out there who needs it gone yesterday. Name brand, recent design, one owner and excellent original condition. Hope this helps. Happy hunting.
They were and are a good sounding speaker. Bringing them up to current specs is really only valuable to anyone who is interested in that speaker. I doubt that you will find that much interest in paying to big a premium for them. Maybe your purchase price plus 25% of your upgrade cost if that.

I was looking at the Meadowlark Blue Heron II speakers. List price about $12K. Used price $2800. I would buy these over the slopes at that price any day.

Happy Listening.
Thank you to everyone who added a comment to my questions. I will take your advice and put them up eventually for $800. But I have another question. Given that I have a McIntosh MA 7000, a Fosgate Signature phono stage, a Linn LP 12 Itok Dynavector 20x h arm set-up, what would you suggest as a few excellent speaker choices in the $2000 range? ~ Frank
You might be able to find a used pair of Joseph Audio RM25s near that price.
I have IS 1.8A's, original. They sound fantastic. A pair of 1.8s rebuilt by Sollecito must sound even better. I should think you can get more than $800 for them. Whoever buys them will get more than their money's worth. I actually think you will have to spend more than the 2K you are thinking of to get significantly better sound.

Why do you want to sell them? What don't you like about them?
I apologize for not seeing your note earlier rnm4 but I decided at the time to keep my speakers. I am once again thinking of changing out my system and google brought me to this thread. I was surprised to see that I was the originator of the conversation. I am going to put my 1.8As up on Audiogon for $1600 as a bid. And I am hoping to get $5500 for my McIntosh MA 7000. I plan to replace the McIntosh with a Peachtree nova220SE for now and I am unsure what speakers I will end up with. Once I sell the amp, which is a far easier sell than the speakers, I will see how it new amp sounds with the 1.8As. Who knows? Maybe I will keep them a little longer.