When were the best tube amps made?

Absolutely right now. Just heard a pair of VAC Master 300 monoblocks. Holy cow. These have me thinking that AMP is the most important component of the audio chain. Including room.

To be honest, I think my question was more about other A'goner's tastes than to attempt to come to any particular conclusion. Whether you wax analytical or nostalgic, your favorite tube amp says more about you than the gear I think. :)

That's cool, and I think is a good approach for this topic. I answered "right now" because the modern state-of-the-art is just insanely good, but I'm definitely heavily nostalgic for the classic vintage tube amp sound. 6L6GC, 5881, KT66, EL34 based vintage amps - sound sweet as hell. Today's SOTA is better, BUT you will pay dearly for it. On a budget - heck yeah a restored classic tube amp is hard to beat. Cost no object, get those new VAC Master 300 monos lol. 

I love my VAC Renaissance 70/70 Mk II, it's 20 years old and still works great  However I am taking it back to Florida this January to get the latest MKIIIs updates, then it will out live me! Handmade in the USA!

@fthompson251 I hear that's one of their classic models, definitely a keeper! There are still fans of their 300B sound before they transitioned to beam tetrodes.

AR fans will hate me for this, but AR SP9 MkIII  has remained one the WORST sounding components I ever purchased, very bad memories of that one. Hybrid design didn't work for me, SP10 would have been much better choice. This purchase probably around 1984-5.

@sns 

Yeah - have to agree. Some years ago, a few friends and I did a shootout of several preamps. There was an older AR hybrid preamp in the mix, and I believe it was specifically the SP9. Tons of gain. It performed relatively poorly. Couldn't even keep up with the entry level Rogue Metis, much less their 99, and an Athena just blew it all away. It was more on par with the Sonic Frontiers SFL-1, also a hybrid. Those hybrid preamps had a steely edge and sounded lean and unnatural compared to the all-tube preamps. 

But that SP9 has seemingly NOTHING in common with the current Audio Research preamps, which are absolutely wonderful. Still a big fan of the Reference 6 here. AR really upped its game in the current era.

@alexberger

Which modern 6SN7 are better than NOS? I currently use Ken-Rad VT-231 from the 1940s in the input stage of my integrated 300B SET. They are not the most expensive NOS but still to change the pair of these tubes is expensive for me.

I haven’t tried the Chinese 6SN7 that get good ratings (note some of their alternate sub types may draw more heater current!). But the Russian Tung-Sol and EH have a number of advantages:

• Can be easily sourced for low noise and tight matches
• They measure VERY high for transconductance compared to vintage 6SN7. These make GREAT drivers for power tubes.
• The Tung-Sol GTB are rated for much higher plate voltages and dissipation - versus vintage 6SN7GT and VT-231 (and certainly 5692) - which some circuits require. A GT tube in a true GTB slot will not last as long. There are some vintage GTA nd GTB tubes and they can be quite nice, but they don’t have the full-on "sweet tone" of the best old GT’s

In my VAC amps I find good vintage 6SN7GT sound best in V1 slots (I like various Sylvanias, Hytron, and Tung-Sol round plates best, followed by Ken-Rads and then RCAs last). But the Russian Tung-Sol GTB are just hard to beat in the V2 driver slots. They rock there. In V1 slots, the Russian tubes lend a bit too much of a solid-state like quality to the overall sound.

For preamps, old vintage 6SN7 tubes are very hard to source to be quiet enough. Microphonics is a particularly big problem there.

So yeah, as per @atmasphere , it just depends :)