Best Integrated All-tube Amp?

One more thing, Josep. As you alluded to in your initial post, you might upgrade your Antal's at some point. I'm sure you are aware that any amp, no matter how punchy in the bass department, is going to be challenged to deliver the goods to you with a speaker that cuts off at 50Hz, as do the Antal's. You might want to consider a sub, or doing that speaker upgrade first, or at least simultaneously.

Just a thought.

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.