300b lovers

@donsachs Yes, new tube types are a daunting investment from the manufacturer’s perspective. My top wish list, without a doubt, would include an ST style 45 (which is the driver of choice in my personal PP 300B build). Followed by a round plate 6SN7, and then maybe an 801A (have not tried Mayers versions yet, but the originals are spectacular).

Regarding iron, I saw Monolith Magnetics mentioned here. I have had great success with everything I’ve tried from them (OT’s, interstages, and plate chokes). I can’t recommend them enough. Their IT02 in particular is stunning, and defies what I thought was actually possible with magnetic coupling.

Getting back on topic, I’m elated to see a fresh PP 300B amp hitting the market. The PP Triode topology has been a personal favorite of mine for many years, and this was most certainly inspired by Lynn’s work/publication of the original Karna, well over 20 years ago now!

I have to say I’m really looking forward to hearing the production Raven :)

The Raven is something else, quite unexpected, really. Don did a superb job on it, no question. The Khozmo volume control, with a L/R balance control thrown in, is the extra deluxe touch.

I have to agree with Eddie about the ST-style 45. Aside from driver use, the charm of the 45 is that it is really easy to make a superb, low-power amplifier with it. It has the cleanest distortion spectrum of any tube I’ve measured (closely followed by the 300B), but unlike the 300B or 2A3, it is super easy to drive. This makes two-stage amps simple ... in fact, I’ve yet to hear a bad 45 amp, while I’ve heard plenty of not-great 2A3 and 300B amps. Good 300B amps in particular are quite difficult.

45 amps also sound louder than you’d expect ... they easily keep up with 2A3 amps, despite what the numbers say. If 45’s were more abundant and at different price points, they would quickly find a market.

I have a dark suspicion that modern 2A3’s are simply below-spec 300B’s, and not related to original 2A3’s at all. Of course, that’s not really true, since 300B’s have 5V filaments while 2A3’s have 2.5V filaments. Modern 2A3’s are quite different than the bi-plate RCA originals ... I’m not sure where they fit, actually.

Returning to the 45 triode, I really think people would be surprised just how good 45’s sound, and how crisp and vivid they are. They are very different sonically than 2A3’s or 300B’s. They actually sound more like 845’s than anything else. Very clean and fast, no murk at all, and nothing like any pentode (no hash or grain). If you can get your hands on a good pair (or quartet) of 45’s, they are quite impressive and worth exploring,

Hi Lynn and Don,

It is very interesting to hear more details about IT versus LC coupling between 6sn7 and 6v6. What is a difference in sound?

Umm, hard to describe. More "there" there. More sense of a physical presence, and a better feel of the performer’s musical intentions. More hall sound. Most of all, a feeling of the performer being in the room instead of somewhere "out there".

Not the usual audiophile verbiage, but it’s immediately evident when you hear it.

By now, the Blackbird is very close to the original Karna, but with greatly improved power supplies and a much more practical monoblock construction, which also improves performance. Full credit to Don for pulling off what I thought was impossible.

As you approach the highest levels of audio, the sound kind of takes a right-angle turn from the usual path of improvement. Instead of just getting more and more clear and vivid, suddenly, there’s a physical sense of musicians being right there in the room, instead of sounding like a very good recording. The instruments have physical size and feel like you can reach out and touch them.

A piano sounds like it’s five feet away, and it sounds BIG. Even "bad" recordings sound like this. Is something being added? No, I don’t think so. Instead, a mechanical quality is no longer there.

This phenomenon is well known amongst triode practitioners. It’s not a secret. Unfortunately, it is almost never heard at hifi shows, so don’t expect it there. I’ve heard it several times at the advanced DIY level. Never heard before from any mainstream or transistor system, which is why I started working with direct-heated triodes in the early Nineties, after hearing and reviewing the Audio Note Ongaku and the Herb Reichert Silver 300B.