Old Amps that can still Kick Butt

Not being a believer that time necessarily = progress, I would like to offer the following example of a sonic gem that has transcended time and can totally kick butt in a modern milieu:

The Robertson 4010. I got one of these about two years ago because it was in immaculate condition, the price was so low and I was inquisitive. I hooked it up and let it warm up for a couple of days. OMG this thing was in the super amp league: Transparency to die for, slam that you couldn‘t‘ believe for for a 50W amp.. Peter Moncrieffe wasn‘t wrong in his review of this amp: this thing is in the Sterreophile Class A component category hands down. Even after all these years.

What amps have you encountered that have defied time and can still kick butt today?

Some class D amps can sound good, but there is just something missing in the sound for my tastes.
I read your interesting and detailed review of the Legacy amplifier, and based upon your past experiences with many other amplifiers, I do believe you when you say that this new iteration of class D is a huge improvement, and a game changer. I wish that I could have a chance to hear it.
Aside from that though, I thought that your comments in the early part of the article concerning "tweaks" being a waste of time were incongruous with the fact that you strongly recommended using aftermarket power cords. Are they not a "tweak" as well? 
@ lou_setriodes

Harvey Rosenberg from NYAL addressed our audio club back in the mid or later 80's, and I had the pleasure of picking him up from the airport.  He wanted to stop by my house, so he could personally "bless" my Moscode 300 and listening room, so we drove 30 miles round trip out of the way.  I have a picture of him in a sport coat wearing a bow tie pointing to my amp!  He was a little out there, but his presentation was riveting and brilliant, as he talked through the timeline of mankind and the importance of music throughout human history.  We thoroughly enjoyed having him as a guest speaker.

The Distech LS-2 was made/marketed by Sal D'Amico, whom I also met at the CES shows.  It was essentially an enhanced ST-140, with some upgrade caps in the signal path, and possibly other minor stuff.  I got to know Eddie Mutka from B&K in Buffalo about 70 miles west of me ....he repaired my Distech amp after I shorted the speaker outputs accidentally (D'oh!).  Good guys....all of them, and fairly down to earth compared to Harvey, LOL.  The son who's getting the amp, isn't fully invested into audio as hobby yet, but he likely will in time, and he appreciates a nice system, and enjoys hearing the history behind the vintage components in his new system.  

Many of the vintage components were designed and built by the same guy who would answer the phone if you called the place of business.  High end audio had a lot of true "Cottage Industry" participants back then.  

roxy54, a courteous and well reasoned reply; thank you! I hope you do get to hear the new breed of class D. 

Briefly, I distinguish between the myriad of tweaks outside the signal path, and products/methods that touch the power and signal paths. I am unusual in the industry, as I recommend the proper way to use and assess cabling is with entire looms/sets from the manufacturer. So, my comments on cables are almost always in the context of that methodology. 

To that end, I have found the efficacy of aftermarket cables to be not debatable when used in sets. I also consider them a component as such, and continuously in personal listening and reviewing they confer as large changes as components - again, when used in sets. Changing a cable here and there ad hoc without a thorough understanding of the manufacturer's intended sound is largely fooling around, a waste of time in that it yields no direction to push the system toward a desired result. 
That use of cables is very much like using tweaks; no directivity and nothing more than hopefulness of a good result. 

If you have not yet worked with aftermarket cables, I encourage you to read my reviews of cables, wherein I explicate my methods. You would perhaps enjoy my latest review of the Iconoclast Cables published at Dagogo.com. For someone who is not yet ready to trust the system, to part with more significant numbers of dollars to test it out, the Iconoclast Cables are ideal, because they use the same geometry, AWG, etc, but with a different conductor for each level of performance. That is not very common in the HiFi cable industry.  
That’s a great story. Mr Rosenberg addressed the Phila Triode Symposium dressed in a full Native American feather headdress that sported a vacuum tube as the keystone of his feather headdress and an Irish kilt. There were many other Audio heavyweights there in the audio press as well as amp designers.

We listened to 8 different SET amps using 300Bs, 845s, 211’s, and 2A3s with a CAT SL1 preamp, the $5K Sony SACD player & 104 dB Classic Audio Reproductions horn speakers with Goertz Alpha Core IC’s & spkr wire. My favorite amp was the lowest powered & least expensive Fi 2A3 monoblocks. Other amps included a 300B SET Prototype by David Berning, Komuro 845 monoblocks, a 110 Lb 211 amp by Wyetech Labs, Caztech Audio 300B amp, Bel Canto, Cary and Audio Note 300B amps.

I took my username from that show that made such an impression on me.

Interestingly, Harvey Rosenberg years later wrote an article in Listener magazine touting 4 pin true triode tubes run in Push Pull Triode as being far superior sonically to SET Amps.