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.
Hi @donsachs , I have a question. I bought and received a power transformer for the driver tube's power supply. This transformer has a central tap for the rectifier. I also bought 4 schottky diodes. What type of rectifier will sound better: a central tapped full wave rectifier or a bridge rectifier?
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@alexberger You might consider HEXFRED rectifiers. They are ultra fast, ultra soft recovery and so are less prone to 'diode noise' (which is actually an interaction between the capacity of the diode junction and the inductance of the power transformer), lower than even Schottky diodes. One tip - unlike silicon rectifiers, the maximum current rating of a HEXFRED cannot be exceeded even for a few milliseconds- there's no 'surge' rating. But they come in some pretty robust current ratings- the smaller ones are typically 8 Amps. There are 1200V versions too. DHTs like a 300b do not have a cathode so cathode stripping during warmup isn't a thing. |
Hi @atmasphere , I will use this rectifier for the driver and the input stages. So i don't need a very high current and power capability. |
@alexberger Since an SET is a constant current load insofar as the power supply is concerned, it won't make much difference if you use tube or solid state rectification. But you might want to consider what happens when the AC line voltage changes. The filament of a tube rectifier cools off when the AC line goes down- so the B+ voltage drops more than one might expect since the rectifier gets less efficient. . Plus you'll find that they each have a 'sound'. If you set up HEXFRED rectifiers properly they are about as neutral as it gets. FWIW we run a separate power transformer for the driver section in our OTLs. We did this so as to prevent any modulation in the output section power supply from affecting the driver. This reduces IMD. Our OTLs run class A2 and have dual output section power supplies so modulation of the supply could be a concern. In an SET a separate power transformer for the driver isn't going to have the same effect since the power supply for the B+ should be nice and quiet anyway. The separate transformer would be useful if you planned to direct couple to the power tube with a cathode follower though. |
