Check out the Bob Carver Raven 350 amps.
There's a number of them that are very high quality and low maintenance.
VAC, Atma-Sphere, BAT, Lamm, Music Reference, Herron, VTL, Rogue all qualify IMHO. Audio Research is one of the biggest brands, but while they certainly have a large number of fans, I have heard plenty of stories and had one personal experience where they are a step down in reliability (and repair cost) vs. those mentioned above.
The Air Tight I once owned was also trouble free, but my read is that there aren't too many sold so it's hard to get a meaningful sample. Cheers,
Also, Audio research can repair any product it’s ever made
But their build quality is kind of standard level. Aside from the knobs. I mean, it's not bad, but the choice of tubes and caps and circuit accounts for 100% of the sound of that gear. It's just basic sheet metal bent and silk screened with a nice front panel on it.
I'm not saying it's bad, but I wouldn't rate it at the top of construction and attention to detail. I'd rather call it perfectly utilitarian construction.
As for the sound quality, that is another story.
Speaking from personal experience alone, Atma-Sphere, Music Reference, Jadis, and AVA (Audio By Van Alstine) are excellent. Audio Research not so much, but that company may have more happy owners than all the above combined, so what do I know? Are they still mounting output tube sockets on their circuit boards? Not a good idea. The VTL retailer I know and his customers are very happy with that company’s products.
I got a Jolida tube integrated amplifier about 8 years ago after reading several good reviews. I've been satisfied with it and have had no problems. One of the things that finally convinced me to get it was the fact that there is no plastic on the unit; even the control knobs are metal. The remote control for the unit is also metal and weighs about a pound; the "buttons" on the remote are steel bearings about 1/8" diameter. I figured if they paid that much attention to such a small detail, I would trust them. No regrets.
@erik_squires4: According to conversations I had with Bill Johnson in the 1970's, those "simple" faceplates were the most difficult and demanding items he sourced for his products. He told me they gave him headaches for weeks and months and that they had to return many of them that did not meet his demanding standards.
Not sure how today's faceplates differ from the old ones; they were a lot of things, but certainly not "simple" to manufacture.
I’m I’m going to throw my hat into the ring as a brand new tuber, and say that the PrimaLuna DiaLogue Premier HP an excellent quality amp that hits way above its $3800 price point, and really sounds excellent. Point to point wiring and a bunch of advanced featUres designed to enhance tube reliability and not drive them to max while still putting out 75 watts in ultralinear mode (switchable on the fly to triode mode). I was actually surprised at how much difference the power amp made in my system!
I really want to save for a new MC275. It has the looks and I like the sound. However, for less money, I can get monoblocks (which I prefer) from Quicksilver or Primaluna. I just wished the QS's looked more pleasing (I know that is weak..but I do like good looking equipment as well). The PrimaLunas look nice, I just wished they were built over here, japan or Europe (I know if they were, the price would be much higher). I was an automotive manufacturing manager and we had so many quality issues with cheaper asian built components (China, etc) that has left me hesitant (yes, I know my phone, TV etc were built there).
Interestingly, I have had more problems with US made equipment. Not so much with gear made elsewhere in other countries. In fact I had US made audio made by a German guy that was dreadful and poor parts. But my Chinese made gear was made great and the customer service top notch. If one is selective, great gear can be purchased from China and elsewhere.
Hand wiring in a tube amp is a good idea. In tube amps with higher voltages, its possible for an output tube to create flyback voltages between the plate and cathode connections. This can cause arcing on the tube socket and if mounted on a circuit board, arcing on the board too. Flyback voltages can occur when the amp is driven into clipping and an output tube is driven into cutoff- at this point the magnetic field in the output transformer collapses and creates a very high voltage- similar to how a spark coil works in a car.
If the amp is hand-wired, sockets are much easier to replace! If there is a circuit board that is damaged by arcing, it can be tricky to repair.
The other issue of circuit boards is heat. Power tubes run hot and this can degrade the circuit board over time. This can be particularly problematic in tropical environments, where its a good idea for the circuit board to have what is known as a 'conformal coating' which prevents corrosion.
Finally, the design and quality of the traces and pads of the circuit board can have a big effect on how repairable the board is- a poorly designed pad (as seen in 1980s ARC) does not survive component replacement very well. So if a circuit board is employed in tube equipment for best longevity it should be 1/8" thick with the heaviest traces, employing a conformal coating, with good pad design and ample cooling holes around any components that run hot.
I agree with Atmasphere. PTP wiring is really the best design for vacuum tube amps. I have a Line Magnetic integrated amp and my dealer told me the company designed the amps based on the old Western Electic blueprints from USA designs. So far, compared to Primaluna, Cary, Rogue and some lower priced ARC models I have liked the sound, performance and customer service from LM Audio and my dealer.
Of course, my limited experience with tubes amps leaves others opinions as valid as mine, even more so. I think BAT, Border Patrol, and Decware probably make great amps...but have not heard them
Agree with bdp24, bad idea to install tube sockets on a circuit board and with Ralph, hardwired, less circuit boards are best EXCEPT in the case of David Berning designs in both cases. I owned a ZH270 for 13 years and never had to change a tube let alone anything else, amazing reliability in spite of circuit board mounted sockets.
Agree with Quicksilver and my pair of 64 year old McIntosh MC-60's which are built like a tank including the heavy gauge steel casing.
ARC power amps blow resistors and bias circuits frequently when a tube fails, causing a return to the factory.
I had a D125 power amp burst into flames with the bias circuit board ruined one time.
Very costly repair.......sold the ARC and never went back to their tube power amps.
ARC preamps have very good reliability though.
Per Jolida amplifiers, I used to have an SJ302a prior to being a dealer and it failed on me. It turned out to be the leads on the circuit board lifting up, which apparently was a common issue. I haven't heard of any similar issues with their newer gear but I would avoid their earlier models at all costs.
Check out Weston Acoustics amplifiers. Australian made in a Melbourne suburb and very highly regarded within the Stereonet community. Earle even winds his own transformers and does all the cabinetry as well. I have owned the Troubadour which is a 20-30 watt integrated amp, depending on what valves are in it, for 8 years now and have had no issues at all. He also makes mono-blocks.
Couldn’t agree more, when it comes to PTP wiring, over PCBs. I’ve been very happy with my Cary amps. Enjoyed a Rocket 88, for a short time. Now(the past ten years), a pair of SLM-100s. Easy and worth the effort to upgrade. Transformer quality is key, when it comes to valve amps, and I’ve found those in my Carys, make the cut. Now that Dennis no longer owns the company, can’t swear to anything, though.