What equipment do you most regret parting with??

Any audio equipment from speakers to phono stages...what do you wish you never gave up?
None. Everything I have now is better than anything I had in the past, or else I wouldn't have it. Though if I were still interested in LPs, I did rather like the Ortofon MC-20 and MCA-76 pre-preamp, and even better, the Stax cartridge.
Odyssey amps, BAT pre
Apogee Divas. I've owned pairs on two separate occassions. Selling the first pair when we moved to a house with a too-small music room; selling the second pair because we needed the bucks. But -- just like that 1960 Jaguar 3.8S Mk2 4-door that, as an always-broke college-kid, I couldn't afford to maintain -- I wish I'd been able to figure out a way not to have to sell 'em.
Hydra 4 right before the prices went up.
KLH12 speaker systems. The only box speaker which sounded right to me. After a decade of Maggies I tried without success to find another good box, but no luck. Maggies again now.
Surprisingly, I miss my NAD 7140 receiver. All the gear I have now is better, but the NAD was very competent. I'm currently doing some maintenance and repairs on various parts of my system, and the 7140 was flexible enough it could pinch hit for just about any of the electronics.

I had to buy a spare preamp just to keep my rig going during the work. It's fine, but no better than the NAD. I should have just kept it.

Presense Audio mk2 by First Sound,itn had a rightness that I can still hear!
Wolcott P220 amps, but I needed the $.
McIntosh MC502 (50wpc) and Celestion SL6si were in smaller room, wish never sold them.
Conrad Johnson PV 11 with phono and the MV52 amp, would have worked great for a second system. sigh
Hafler DH110 pre I built as a kit.
Yes selling a Goldmund studio table with matching 3b arm,a pair of original Proac super tablettes, and the quicksilver mono amps, man what a combo for musical enjoyment.
Pioneer CT-A9X cassette deck,
Kenwood Basic C2 pre-amp,
Yamaha TX-1000 tuner,
Sony CDP-91 10 cd disc changer,
Sony JA20ES minidisc recorder. That`s it!
Although we all have sold stuff we once owned and maybe still would like to have, we all got rid of it for a reason: something better came along. I bought Yamaha NS-690 speakers and loved them for a while, but then I heard the Rogers Studio 1s....which I kept for 20 years! I then found a nice set of Yamaha MS-1000M's, which are even older than the Rogers, so bye-bye Rogers. Do I regret getting rid of them? A little, but not enough to get me interested in getting them back.
Talon Raven C speakers- was too impatient with their performance and was unwilling to work with them to optimize their performance-should have gotten rid of my McIntosh 6900 instead and found electronics to make the Ravens sing- never got to hear what they were capable of before I sold them.
An original Keith Monks Audio Labs record cleaning machine.
Was moving a lot at the time and was sick of carting it about. Regretted selling it the moment it went to the shipper on it's way to it's new home in Germany.

Also a pair of Magnepan SMGa. IMHO a superior loudspeaker to the current MMG.
My Audio Research SP-6A with 6 Telefunken ECC83 in it. I gave it to my brother in 95 and he donated it to charity.
I regret selling my Teledyne AR-9 Speakers, mostly because I had to give them away because of Bluebook Value,
still wish I had room to store them.
The radio in my 78' FJ-40 Landcruiser...well, actually I regret selling the whole truck! Hmmm, audio gear? I have had attachments to various pieces of gear, but no "regrets". Some good memories of fine gear from the past though: Wright Mono 10 amps, Mesa Baron amp, Silverline SR17 speakers (I've had three different pairs just because I missed the previous one I'd sold), Klipsch LaScalas (sold one pair, still have a pair that is in storage...temporarily). You move on, not necessarily always upward, but hopefully ever evolving and always involving you with the music we all love.

...I do not want what I have not got.

Verity Audio Fidelio's in the makore finish---I bought another pair and will not part with them!!!!!!!!!!!!!!!
Placette active linestage
A Threshold SA3. Bought some panel speakers and thought I'd never only need 50 watts again. I think this is the last piece of equipment I have sold (over 17 years ago). Never made that mistake again, but are my closets full of stuff! :-)
My Vendetta head amp I had a 2B it was great I wish i never sold it . I would like to find one again if I had the money oh well someday ????
Vendetta Research phono stage! What was I thinking!
My Linn Sondek/Ittok turntable/tonearm. I gave it away for almost nothing.
I will miss...

Conrad Johnson Premier 14 It had a beautiful sweet sound.

Tandberg 3014a an awesome machine

Marantz 10b Incrediable musical instrument
The only piece o equipment I regret selling was my Portal Panache. If that thing had a remote control I'd be listening to it now. Cmon Mr. Abrams.
CJ Walker J55 turntable...a poor man's Linn. Got swiped while in storage.
My dad sold off his old McIntosh tube equipment without even thinking of giving it to me. Does that count? A nice C22 preamp, a MC240 amp, and some Bozak speakers. Yeah, I'd like them back!
I shall never forgive myself for parting with my Audio Research SP10 MKII !! The phono section had a sonic signature that "lured" you into long hour listening sessions!!

I find myself sometimes falling into "audiophilic depression" lamenting over it's absence.

That soon goes away when I remember how much it cost to "retube" that puppy!

But it still remains as my "long lost lover"!!

I had three of the four Nakamichi 600 series components; the tapedeck, tuner/preamp, and power amp. The tuner/preamp was especially sweet because it had one of the best sounding tuners I've ever come across. The act of tuning in a staion was a particularly sensual process because the action of the huge tuning dial was so effortlessly smooth. Together, these components were spectacular looking; products of a uniquely Japanese aesthetic and advanced industrial design. Alas, I unloaded all but the cassetted deck due to a variety of pressures.
Had a great pair of Dutch speakers that were a hand me down from my grandfather. I got them when he died, and when they went south after a twenty year lifespan, I was truly bummed.
Martin Logan Aerius I and SL3.
Quad 33/303 with ESL speakers. Did'nt have room for them. Sold them in mint 'mint' shape.
Sequerra Met 7s.
i love to have that Goldmund Studio with 3F arm that I sold years ago for my 2nd TT today. I will spend more money to buy another or buy something as good.

I also sold a Mares Connoisseur 2.0 sometime ago - a mistake in hindsite.
McIntosh MC2000, it always sounded good witht whatever it was paired with, and looked bitchin!
Lamm LL2 Deluxe.

I'm presently running long balanced ICs and short speaker cables, so the LL2 won't work in my system. But, if I ever reconfigure to allow shorter speaker cables, a LL2 Deluxe will be under strong consideration.

A silly bargain at the current used price of ~$2500.
A Musical Fidelity A-20 (20 watts Class A) integrated, glossy black minimalist front panel ... great synergy with Nautilus 804s ... convinced myself that some expensive Classé amps would make the B&Ws sing ... and they did, but the A-20 was a nicer match for those speakers ... I always regretted not holding onto that MF integrated ... it didn't even cost that much when new ... truly a bonehead mistake
A pair of Mac 240s hooked up to a Marantz 7C driving a pair of Cartwell LS3/5as. Shear synergy.
My B&W CDM1 speakers. Sexy looking and good sounding, I'd love to have them in my second system today.
Dynaco amp. Bought it for a tenner and sold for a hundred. What was I thinking?
My Impulse H1 horn loudspeakers that are In another continent.
A tear In my eye.
Eico HF-60's. It had great tubes and I did a few upgrades like RCA's, Speaker terminals,removed input pot and put in some better caps.

SOTA Saphire with SME tonearm and Grace Ruby cartridge. Sold it for $100!!!!!!!!

Why? Because I was STUPID.

I like the TT I have now better (Linn LP12), but still, the stupidity still staggers me.
Apt Holman preamp and Apt 1 amp, would have made a great second system.

KEF RDM 2, one of my favorite speakers regardless of size or price. Would have sounded good with above components in a second system. I have been looking for a mint used pair ever since.

Pioneer PD 65 CD player, great player that I traded in for a P.O.S. transport.

There are many more but those popped into my head first.
Parasound A-21
Marantz 7c, pair of MAC 240s and Chartwell LS3/5as
Infinity Reference standard 1 (thought I might be able to make small speakers sound as good, Wadia 860.... looked and finally replaced it thought it was depreciating but 8 years later they go for same price I sold it for originally, Matched pair of Entec Sw-1 (the only sub that ever sounded musical,
Yamaha CR 1040 receiver. Sound, build and looks, it had it all. Had long moved on, giving it to my sister. But is was so nice I have come to regret it. I could have easily used it in a secondary system.