Pass LabsB1K Nutube PreampusedPass Labs B1K Nutube Preamp>>>>>>>>> I should post that I had to take this listing off market to deal with a family emergency (which is still ongoing unfortunately). I am relisting and appreciate ...550.00

Pass Labs B1K Nutube Preamp [Expired]


no longer for sale

 >>>>>>>>> I should post that I had to take this listing off market to deal with a family emergency (which is still ongoing unfortunately). I am relisting and appreciate your understanding.<<<<<< >>>>>>> >>>>>>>>
  You be the judge. I am trying an auction here for the first time. I enjoy making these NuTube preamps so much. Almost every one of them is one off, i.e. original. This one has a story to go with it. Simply put, it was to become my own personal phono stage when I started. Parts were not available, so I built a different phono stage instead. In the end, I sold the first attempt to another builder, and decided that this was to become a B1 pre. So here we are.  

The SP1 NuTube is a dual, directly heated triode. With this circuit the gain is about 16, and the noise is very low, which is pleasing.



   A 4 input B1K NP preamp design, with one output. Not much has except I am stickler for quality, so every stinking part used here needs no excuse as to why it was chosen. All the way from those dear Manley Labs RCA connectors on the back of the unit to the EIZZ volume control, to the Elna switch, and yes, even the wire throughout is one of my favorite things. When you use input #1, the wiring is made by Nanotech/Legenburg. It is a rectangular copper wire, Neotech/Legenburg UP-OCC Mono Crystal  design. Looks cool sounds great. The three other inputs use a silver plated copper wire with Teflon insulation and a jacket of Kevlar IIRC.
 >>> As with all my Nutube builds attention to vibration control is unsurpassed. Yup, everything from the soft silicone footers sold by Hudson Hi-Fi, the silicone board mounts (even softer silicone), and unmistakibly the best Nutube product that I have ever seen, offered by Pete Millett. Dynamat is used in critical spots inside the chassis. That about covers the isolation/vibration control.   Moving on, I am using an expensive trim pot for the bias adjustment of the NuTube. I prefer this one because it is sealed, it uses a plastic resistive track rather than carbon, and is a tight tolerance. MMM, they cost $21 ea! as compared to a couple of dollars for a trim pot that I am less than impressed with.  
>>>>>>>>>> Ah yes, the power supply. Ok, lets start with a dual bobbin transformer instead of other types. After  learning about various types of transformers, I found that this design allows less noise to come through its windings. Yes oversimplified but to the point. The power supply regulator is designed by AMB which I also found to have the merits of ejecting noise, supplying a constant current, and a stable voltage in spite of powerline fluctuations. In short, remember this was the product that first intended for myself, so there are no apologies to be made.   
Addendum:  I just thought you should know what you pay for. I am giving an example of two parts. The photos of the two Bourns variable resistors/trim pots The original on the right works fine, but the one on the left is much higher precision/Costly. It is also is rated for 1 watt, which is way above the need here. Mostly I prefer it because of the ease of adjustment. No, I doubt that it affects sound quality. The original pot uses a carbon track for resistive purposes, this one uses a plastic track. You might say it has less grit in the adjusting. The costlier part is also a sealed unit. Probably this only matters to a guy like me. The cost is 15 times higher than the other. 

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