300b lovers


I have been an owner of Don Sachs gear since he began, and he modified all my HK Citation gear before he came out with his own creations.  I bought a Willsenton 300b integrated amp and was smitten with the sound of it, inexpensive as it is.  Don told me that he was designing a 300b amp with the legendary Lynn Olson and lo and behold, I got one of his early pair of pre-production mono-blocks recently, driving Spatial Audio M5 Triode Masters.  

Now with a week on the amp, I am eager to say that these 300b amps are simply sensational, creating a sound that brings the musicians right into my listening room with a palpable presence.  They create the most open vidid presentation to the music -- they are neither warm nor cool, just uncannily true to the source of the music.  They replace his excellent Kootai KT88 which I was dubious about being bettered by anything, but these amps are just outstanding.  Don is nearing production of a successor to his highly regard DS2 preamp, which also will have a  unique circuitry to mate with his 300b monos via XLR connections.  Don explained the sonic benefits of this design and it went over my head, but clearly these designs are well though out.. my ears confirm it. 

I have been an audiophile for nearly 50 years having had a boatload of electronics during that time, but I personally have never heard such a realistic presentation to my music as I am hearing with these 300b monos in my system.  300b tubes lend themselves to realistic music reproduction as my Willsenton 300b integrated amps informed me, but Don's 300b amps are in a entirely different realm.  Of course, 300b amps favor efficient speakers so carefully component matching is paramount.

Don is working out a business arrangement to have his electronics built by an American audio firm so they will soon be more widely available to the public.  Don will be attending the Seattle Audio Show in June in the Spatial Audio room where the speakers will be driven by his 300b monos and his preamp, with digital conversion with the outstanding Lampizator Pacific tube DAC.  I will be there to hear what I expect to be an outstanding sonic presentation.  

To allay any questions about the cost of Don's 300b mono, I do not have an answer. 

 

 

whitestix

@stephenr First off, thanks for you polite post on this thread. I bet your 12B4 preamp sounds great. I have tried removing the Raven preamp and going direct to the amps from the Lampi Pacific DAC via xlr. It sounds very good. It doesn’t sound nearly as good as with the Raven active preamp in the chain though. Over the years I have experimented with various passive preamps built with top notch volume controls and none were as satisfying as a really high end active tube preamp in my system to my ear.

As for the direct coupling, no I didn’t experiment with it in this project. I have heard it in other amps. As Lynn has described above, there were reasons for avoiding it in this particular project. I am sure you can make it work well in your amp though and I suspect it sounds very good.

Don and I are moving towards production of the Blackbird 300B amplifier. We’re now using triode-connected KT88 drivers running at twice the current (56~64 mA per KT88) and one-third the plate impedance (Rp = 700 ohms) of the previous drivers. Not only that, owners will be free to use matched pairs of their favorite 6L6, KT66, KT77, 6550, or KT88’s, with no bias adjustments needed.

The tube lineup is: 6SN7 input, KT88 drivers, 300B outputs, with VR105 shunt regulators. As before, fully balanced Class A from input to output. Special-design Cinemag input and interstage transformers, with custom Monolith output and power transformers. 18"/457mm full-width monoblock chassis with two isolated audio-circuit and power-supply sections, a slow-start circuit, surge protection, and a 12V trigger option. (No AC power goes to the front panel, just DC trigger voltage for the slow-start circuit.)

Don and I anticipate Spatial Audio (of Salt Lake City) will start manufacturing in November 2023.

Amazing to watch the arc of the development and completion of these stellar monobock amps.  Just wonderful.  

Don and I were talking on the phone today, and I realized that, of the four to five key people involved, we might have two centuries of professional design experience in audio. I think Don and I might have a century; I filed my initial Document of Disclosure for Shadow Vector in 1973, and Don’s been doing vacuum tube amps since he was sixteen.

And the development arc has been interesting: the PP Karna 300B of 2003 has merged with Don’s PP KT88 Kootenai amplifier.

The Kootenai is no slouch: a classic Mullard circuit (as used by Marantz and others) with 6SN7 input and drivers, PP KT88’s biased into near Class A, advanced B+ regulators, all on a compact stereo chassis. A clear step up from restored Marantz, McIntosh, and Citation II amplifiers, and the best Golden Age style amp I've heard.