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. 




I have a thorough dislike of working with lead-free solder.  Nothing flows in a point to point build like a good 2% silver solder. 

@donsachs That is why its worth it to work out the math. The lead content in your product is a percentage allowable. Since you have a lot of transformer weight and otherwise the circuit is fairly simple, my surmise is you can use leaded solder with no worries. But you'll want to look at the regulations and do the math to know for sure.

We'll cross that bridge when we get to it. So far, we haven't ordered any multi-voltage power transformers. When we do, we'll dig into the applicable CE regulations ...

The gear could easily be wired for 220-240 VAC 50Hz.  Everything we use supports it except for ordering multiple primaries on the power transformers.  Again, the project must get off the ground in the USA/Canada.  If they are selling, and people from Europe are inquiring, then perhaps Spatial may be interested in that market.  Hard to say.  If demand is outstripping supply there is no reason to make your life difficult dealing with markets outside N America.  Down the road......maybe

I should mention additional heating from 50 Hz working is a non-issue. The design of the power transformer, rectifiers, and regulators are extremely conservative and run very cool. Don has measured the thermals all around the chassis, and we have plenty of headroom everywhere. So no issues there.

I ask again this technical question again. Which rectifier is better: full wave or bridge?

My driver stage power transformer has three taps: 250 0 250 and supports both - full wave and bridge. Full wave affords use x2 times bigger DC current. Why do many people prefer a bridge rectifier over full wave?