THE HOLY GRAIL OF AUDIO: THE CLASS A SINGLE ENDED TRIODE VACUUM TUBE MONOBLOCK AMPLIFIER ! 

The cap on top of some tube designs always connects to the anode (plate) and is where the high voltage is applied. As voltages get higher for many tube designs in order to be able to drive more wattage out of them there's a danger of the other elements and or connections arcing over to the anode inside the tube, or at the connections on the base, so they connected the anode at the top to prevent this.

I have a pair of the VAC 452 Tube Music Block mono amps. I love them. It's cool seeing all the different types of tube amps.

Well, Fred Flintstone already commented, but connection to the top has nothing to do with being direct heated or not. The top connection by separate wire is normally the anode ( plate ) connection.

great collection of set amps!

Very nice collection and great seeing all kind of makers like EMLs and Hashimoto featured and dispelling the common BS floating around. Btw most push pull tube amps now are class A or AB.. nearly nobody I think does class B tube amps where you'd have the crossover distortion you mention.

Great job nice tube lesson , more please

Thoroughly enjoyable. Thank you

Good knowledge Mikey. Thank you

I used to love Tube Rolling and Listening to music at the same time in the Mid 70's with my Harmon Kardon Citation! Did have to let it cool down between sessions! 😉

This was a great video Mikey!! Someday would love to hear that monster

Looks like a lot of fun 😜💞

Nice display and explanation.

LOL. I love that, this puppy will heat your room in the winter time... as if you can find that tube amp, amazing. I wish I could hear these in person. I am starting to getthe tube bug, but not on this level. I would be curious what your recommendations for a new tube amp ( that is readily available on the market) would be. There is so many new tube amps available today, particularly from China.

best of the best audio channel!

As you say, it all depends on the sensitivity of the speaker. A 2A3 tube amp will give you the same audible output as a 300b tube amp if the speaker is 6 db more sensitive.

Fracking Amazing video. 👏

This is the coolest thing I've ever seen

Gr8 vid. I had a pair of 805 S.E. mono amps, with 1 of the older 805's per amp & with a (scarily thin) wire that was anode connected & exited from the tubes top cap connector & back down into the Output Trannie ...I assume. I put them aside for a 80w class A amp because those tubes jobs didn't give a good low'end on a pair of very inefficient Audiostatic e/stats that were listed at (an optimistic) 83 db/watt/metre, but seemed to be quite lower than that) But when I tired of the e/stats, those amps sound glorious on vintage Tannoy 15" D.D. speakers (now 53 yrs old, made in 1969 & working fine (proof of gr8 engineering imo.) Tubes produce a seductively warm mollycoddling glorious sound, even the old vintage tube amps like Radfords (2xEL84's per side) or Rogers (EL84's per ch') or Quad's (2×KT66 a side) I grew up on those vintage amps which we cheap s/h buys before eBay came along. I very much prefer them compared to solid state if they have suitable speakers to play into. They draw me into the music better & can be analytical but in a delightful, cosy audio embrace. Never tried 300B's that would match my very efficient vintage Tannoys very well ...I reckon. I was most surprised at the vastly different looking 300B's available. I cannot imagine the best ones being less than expensive, still, tubes last longer than most people I've heard claim, I know from vintage tube amps I bought with original Mullards, still wotking fine after 30 to 50 years, tho I don't know how new ones might have improved the sound. I wouldn't be one of those guys who bought new tubes all round every 2 years or so. Pre,amp & low level signal tubes seem to me can last nearly forever! Power tubes I assume last least long, the do the hardest work, I suppose.

I fell in love with the Margules i240 tube amp powering Scansonics at Capital Audio Fest. I own those Scansonic mb6b and really tempted to get that amp. I think you mentioned you liked that amp/room.

Great showcase of SET. Really looking forward to knowing what that last one was. I am just getting into tubes and would appreciate any advise on what to pair with spatial audio high sensitivity open baffle speakers. Just starting out so I'm not wanting to break the bank. I thank you in advance for any advise. Cheers