Best Integrated All-tube Amp?

The two best that I have heard are the Audion PX-25 and the KR Enterprise BSI 18. Both are SETs. I am using the KR in my system and it is, simply, the best amp I have used in my system, and that includes all separate preamp and amp combinations.

I was going to mention Audion as well, as we had a Silver Night MKII (300B) integrated (with only one source input). Audion also makes the Sterling EL34 12W SET with remote. Gorgeous sounding amps, and yet the worst customer service I have ever experienced. If you need to service one--SET amps are not complicated--find a local, reliable tech. That's all I will say.

I am overwhelmed (and humbled) by all your responses. I really appreciate them.

Most of you mention that single-ended amps have their own disadvantages. Which ones are they? I guess class-A circuitry does not last as long as AB, does it happen the same thing with single-ended vs push pull?

You guys are right about the price tag. Though price is a fuzzy line here. I mean, if McIntosh would make a 70wpc single-ended as well designed as the Viva, I would probably be willing to spend over 6-8 grand (used.)Specially if it is integrated (key variable when you live between NYC and Europe.)Plus, switching the voltage at a Mac is rather easy, since the tranformer accepts dual voltage.

Also,about trusting one's ear. Essentially, I must agree on that statement. But it is just too hard to go auditioning all these brands, even in NYC. Dealers just try to push their stuff and have no time for someone who just wants to sample their equipment.

Thanks for your honest feedback,

Josep

Single-ended amps tend to have wild output impedences that interact greatly with most speakers, the result being that the frequency response of the speaker can have a number of huge dips and crests, i.e., the sound is not accurate nor faithful to the source. The sound can still be very pleasing, but oftentimes it is not. You don't have to worry as much about this issue with push-pull amps.

You really need to know which single-ended amps go well with which speakers, and as a general rule, you need to use them with speakers that do not dip below 6 Ohms or so (8+ Ohms is better). Single-ended amps tend to be low powered as well, meaning that you need to use them speakers that are extremely efficient (92 db+/watt/meter at a minimum).

Finally, you really need to spend some money to get a good single-ended tube amp (or any tube amp for that matter), as the output transformers in them are critical to their performance and good transformers are extremely expensive. Lamm, Air Tight and to a somewhat lesser extent, Jadis (good, but way overpriced) are examples of excellent (build quality and sound quality) single-ended gear. CAT, VAC and Audio Valve make excellent (build quality and sound quality) push-pull amps.

As for dealers, call Dave Lalin at Singer or Bob Herman at Lyric and tell them what you you are looking for. I think you'll be treated properly.

I was the first person to respond on this thread and I just checked back to see that many other people have provided some useful and helpful information.

I am more familiar with solid state gear and my Jolida 302B is my first experience with a pure tube setup. It has point to point wiring, excellent build quality, and a full range sound that sounds both accurate and emotionally involving to my ears. I have never heard the stock unit, but I am thrilled with my Level 1 mods from Parts Connexion.

I have my 302B partnered up with an Origin Live Ultra TT/OL Silver arm/Shelter 501 II cartridge/Bel Canto Phono1 TT setup, a modded Music Hall CD-25 CD player, and Quad 21L speakers. The system is supremely satisfying (especially as a secondary system). When you look at just the CD player, speakers, and 302B, the system is a sonic bargain. Of course you can get a better sounding system, but the rule of diminishing returns definitely applies.

My Jolida 302B costs far less than my primary system, but it comes extremely close in terms of musical involvement and enjoyment. I wish I knew more technically in regards to the tube knowledge demonstrated by many of the others on this thread. However, I can say that for the money I have not heard a system I like any better than my modded Jolida 302B.

Regards,
Greg