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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
lynn_olson's avatar
lynn_olson
328 posts
 

I am impressed you took the project that far, but the minimum requirement for 10,000 units on an unknown tube is a steep hill to climb. Even at OEM prices, that’s a half-million dollars on a gamble. The "X" tube would have to be very very good, and very very popular, for that gamble to pay off.

In other news, the all-IT, no coupling-cap version of the Blackbird is the best version yet. The LC coupling on the 6SN7 is going away and getting replaced with a custom IT with 18 Hz to 35~40 kHz bandwidth. This gets rid of six parts - a pair of 100 Hy inductors, a pair of copper-foil coupling caps, and two 220K grid resistors. No RC coupling, no LC coupling, and no current sources, either as plate loads or in the cathode circuit. The signal path is copper wire, high-nickel magnetic cores, and vacuum tubes.

As Don mentioned on a recent phone call, there is no direct electrical coupling between any of the stages, which filters off any RFI incursion before it gets amplified. Homes are much noisier in the RF spectrum than they used to be, with Bluetooth and WiFi everywhere.

Tube lineup remains 6SN7, matched pair of 6V6, and matched pair of 300B. Tube rolling is welcome so long as pairs are matched.

donsachs's avatar
donsachs
282 posts
 

@eddie138 Thanks so much for chiming in.  Really interesting post and the economics are of course as you stated.   It is not like getting a custom capacitor made where you only have to have 100 of them for an order.   I guess that explains why manufactures stick with the known tube types where there will be a market.   Now if someone would start cranking out moderately priced 45 tubes......:)  But you would have to sell a lot of them to make it worthwhile.

eddie138
3 posts
 

@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 :)

lynn_olson's avatar
lynn_olson
328 posts
 

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.

lynn_olson's avatar
lynn_olson
328 posts
 

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,

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