I look forward to hearing this amp at PAF. I'm currently running 300B PSET Monoblocks (transformer coupled) and love the way they sound.
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.
Showing 9 responses by jaytor
@lynn_olson - what are your thoughts on using a balanced input stage to drive a single ended 300B? My front end hardware is all balanced and I like using balanced connections. I’m thinking an LTP with a CCS on the cathodes and a push/pull interstage on the anodes. Output of the IT driving a single 300B with fixed bias connected to the other side of the IT secondary. I haven’t decided which tubes to use for the input stage, but was thinking about triode strapped D3As. I have a nice pair of Monolith Magnetics SX-11 output transformers that I want to use. |
@charles1dad - Thank you. @atmasphere - One of the reasons I was thinking of using single section tubes was to improve matching. I've noticed this section matching problem in LTPs I've been playing with, particularly with some of the soviet tubes (e.g. 6N6Ps) where the quality control seems to be lacking. Are there any tubes that, in a PP IT loaded design, would be reasonably linear and provide enough drive for a single 300B without a cathode follower stage? I'm confused why a bipolar supply would help. I'm assuming I'd need to have some kind of negative supply for the fixed bias circuit which I would also use for the LTP CCS connection, but I would expect this to be around negative 100V. Alternatively, I could use a balanced input transformer with the secondary center-tap tied to a positive voltage to allow enough voltage across the CCS tied to ground. |
I visited the Spatial Audio/Don Sachs room this morning and again this afternoon. This was the first room I visited today and I don't think I heard any rooms I liked better today, including some with systems that cost MANY times more. The friends I am with felt the same way, and we often don't agree on what sounds the best. Congrats Lynn and Don for building a killer amp and preamp. Very impressive. |
@atmasphere - If the input of the next component is balanced and not referenced to ground (e.g. transformer coupled), I don't understand why it is necessary to decouple the output in the source component from any ground reference to achieve the full benefits of balanced connections. Can you please help me understand. Thanks. |
@atmasphere - makes sense. Thanks for the detailed explanation. |
@lynn_olson - First, let me state that I've really enjoyed your, Don's and Ralph's discussion of amplifier design and tradeoffs. I've been intrigued by Alan Wright's designs (I'm currently building a line stage preamp inspired by the RTP3D). You've done a good job explaining the downsides of a differential output stage. Alan was a big proponent of this approach so he obviously felt it had advantages. Since he is no longer with us to defend his design, what do you think are the positive attributes of a differential output stage in a tube power amp? |
@lynn_olson @donsachs @atmasphere - Thanks for your responses. My system is bi-amped with a SS amp driving the lower three octaves, so I'm primarily concerned about upper bass on up. I'm pretty happy with my current DIY 300B PSET monoblocks, but I like to tinker. I've primarily been building electronics based on other's designs (at least at the module level), but I've recently been trying my own designs (heavily influenced by others). I think I want to build a PP amp as my next amp, using either 300Bs or 2A3s. My main speakers are pretty sensitive (98db/w line arrays) so I don't need a ton of power. I'm still thinking about what approach I want to take. |
@lynn_olson - that’s a cool idea Lynn. There are certainly plenty of audiophiles out there with KT88 amps that are running them in triode mode that could benefit from these, not to mention folks with KT88 amps that don’t currently have a way to run triode connected. i don’t currently have a KT88 amp, but would probably build one if such a tube were available. |