Best 300b single-ended Tube amp. for the $

Good choice Saffy,

The PX-25 is one of the finest amps I have ever heard. It has a musical quality that is entirely unique, one reviewer coined the phrase "as if instruments were lit from within". I agree.

The PX is 6wpc, but has current capabilities beyond the normal 6-10wpc SET amp. I suggest speakers of >95dB to really let the amp shine.

I'm partial to single-driver, or more accurately, wide-range driver speakers. They usually feature a 1st order, or no, crossover at all, which along with the single point of origin for the majority of the frequency range leads to a greater time and phase coherence than multi-driver speakers with higher order crossovers.

By "musical coherence" I mean that is as if all sound flows from a single musical tapestry. Not one dimensional, but a beautifully woven soundscape of depth and nuance. Done properly, it is awe inspiring and there is nothing like it.

But, that isn't the only, or even best, approach. Like everything in audio, which is best for you is a personal choice and may not be the same for anyone else.

Welborne Labs, which also makes fantastic SET amps, has a great page listing speakers that mate well with SET amps. They also have a short primer on proper speaker matching.

The best advice I could offer for anyone interested in high-eff speakers would be to check here, Audio Asylum's High Efficiency Speaker forum, and on the Fullrange Driver Forum for a horn or high-eff listeners group in your city. At the very least, there might a few owners in your area. Ask if you can check out their systems. The more you hear the better.

Take your time before jumping in, high-eff systems are much harder to get right than most people would think. And enjoy the learning process.

I think I may have it here.

Recently off ebay I found a Spark/Cayin 300b single ended from about 1997 design , but this appears to have been a model year 2000 unit. I retubed it with a set of VAlvo e188cc vintage and a set of Sylvania 6sn7. The 300b are kr audio 300b.

Playing a variety of jazz LP's and some varied blugrass, female vocal, strings, horn section, with some clean plucked bass. Just finished some odd Japanese album I was lucky to find today. Linen jacket and early Victor pressing. Gorgeous

Sounds are playing through some vintage Altec 604's with a clean sealed sub for the nether region. The Altecs are housed in a heavy solid Teak ply cabinet. The subwoofer has a cabinet that is quite dense. Very fast and bass notes are complete and full throughout the range

A friend that's a musician was here and we might have had some Adult beverages... but he'll attest

Something clicked totally within the system this eve. I finally figured out two key things that perfectly hit the stage-like realism at low non-fatigueing levels. So solid yet so there... yowza, nirvana.

In looking for an equivelent system, I haven't heard another like it.

Cheers
RW

Saffy
The KCS Back Loaded Horn by Johnk for sale on right now on AG would allow you to use a wide variety of 300B or 2A3 amps. KCS offers many other designs of great value. I bought the BLH and love it. Please take the time to look at this speaker. 98db. 8ohm load.
http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1173796424

Thanks everyone - a wealth of info

Think I've nailed it down to the PX-25 amp

Really like what I see in the Druid MK-IV, + they let you try them for 60 days.

The abbey line looks nice, but don't get as good of reviews as the Druid, + they have less chance to pass the living room furniture police.

1- your thoughts on Abby vs Druid, and/or other Sp. options?
2- are theses low power amps sensitive to what speakers cables one uses?
3-am I ok going with just the PX-25 passive, or do I really need a line stage?

Hi Saffy,

In response to your questions:

1. Both the Druid and Abbys are great speakers, especially Abbys for the money. I think the two do really well in small to medium sized rooms. Both benefit greatly from a subwoofer. Although, the Druids deliver surprisingly deep bass for a cabinet that is only 6.5" deep, really perplexing how they do that.

Zu seems to be one of those products that evoke strong responses, both pro and con. Some of those who dislike them have actually heard them, a lot have not. You have to decide for yourself and Zu's 30-day money back guarantee assures just that. Not many other manufacturers are that generous.

Oddly, we tried my PX-25 with Abbys but actually preferred the $800 Almarro A205A with it. The A205A is a single-ended pentode (SEP) amp that has sonic performance leagues beyond it's price. Paired with the Abby, it is sublime when you take cost into consideration. A few cheap upgrades to the Almarro make it a real giant killer.

As for other speaker options, please let us know your room dimensions, average listening level, and how far you sit away?

2. Low-power, high sensitivity, systems are far more revealing(IMO) to component and cables changes than high powered systems. Noise is also a big problem. For example, when I had 90dB speakers, my system was dead quiet. But, when i switched to 97dB speakers and <8wpc SETs, it became glaringly clear that I had a loud 60Hz hum problem in my household electrical system. The hum was clearly audible at my listening position 14+ feet away. I had to re-ground my breaker panel and then use balanced isolation transformers before my audio system before I could get it truly quiet. Never knew the noise was there with 90dB speakers.

I've also found that cable changes are far more pronounced with the high-eff system.

3. If you only have one source, then no need for a linestage. Whether the PX-25 passive will work well for you is really dependent on the output of your cd/turntable/tuner, etc. The PX has an input sensitivity of 0.7V, so anything with 1.5V output will do really well as long as you keep interconnects short. I probably wouldn't use anything that has under 1.2V output, a little headroom is always good so that the sources output stage isn't stressed at all - they distort badly when pushed hard.