FET Preamps
     Allen Wright goes into this in great detail in his Preamp Cookbook!  Get the transistors - at reasonable prices -  from MCM, 2SK170, 2SK369, single or - I believe - 2SK398? dual version in the BL? or V (medium or high IdSS versions) - MCM does not differentiate, so you can ask them to check, or take your chances. The 2SK147 is no longer with us but these use the same die!

John
(USA)

    The whole issue of printing would disappear with the creation of a PDF file for the Tube CAD Journal. Thanks to  readers Johan, Ken,  and Yury the latest PDF renditions look much better and print beautifully. One problem remains: the files are too large because they hold two identical versions of the Tube CAD Journal issue! Every variable has been tried and it still comes out with a redundant internal file. Once this bug is stamped out, I will post a PDF version of this journal.
   As for printing right now, set your browser's page setup options to .25 inch margins and clear the header and footer entries.
   As for the Ultrapath circuit, the blame does not belong to John Atwood, as I believe it is from Jack Elliano of Electra-Print. I have heard good reviews of his amplifiers and transformers, but I am sure that it does hum, you see it is only half wrong, or rather, half right. The complete UltraUltrapath circuit is covered in the second issue of this journal in an article titled "Lowering the Single Ended Amplifier's Output Noise."
   As for the hot line voltages you are experiencing, where I live on the California coast, the wall voltage is 122 VAC. But I have a friend who live 70 miles north in San Francisco and his wall voltage is only 108 VAC. He live in old apartment building that loses 2 volts per floor. Consequently, his heaters are being under heated.  What to do?

    The answer might be to place the secondary of a 8 volt transformer in series with the primary of your amplifier's power transformer. Depending on the phase relationship between these two windings, the amplifier's transformer will see either plus or minus 8 volts on top of the wall voltage. Because this second transformer need only supply the same amount of current that the power transformer draws it cannot be that physically large.
   As for FETs for hybrid preamps, thanks for tips. I have a nice stock of matched 2SK147s and 2SK146s, I haven't had to shop for any for quite sometime. A few words on their use. They are amazingly quiet, which I dearly appreciate. Yet I remember once listening to a $3,500 FET based preamp from one of America's premier solid-state high-end manufacturers that was wonderfully quiet. But after 20 minutes of listening, I felt that something was missing; it was as if it lost not only the noise, but some of the music as well. Four voices became two; room echoes vanished. Of course, some recordings benefit from this subtractive function, but most don't. In other words, more experimentation is required.
   Here is another example: I recently made a test of several types of resistors, metal film, bulk foil, carbon film, carbon composition, non-inductive metal film. The test was easy, as only one plate resistor needed to be replaced. The surprise was just how good the carbon composition sounded. Yet, I still remember when I had replaced every carbon resistor in a solid-state preamp with a metal film resistor. The metal film beat the carbon handily. If one carbon resistor sounded much better than one metal film resistor, how can 50 metal resistors sound better than 50 carbon film resistors? Is it possible that the sonically detrimental effects of a metal film are not additive, but those of the carbon resistor are?
    The subject of testing components is deserving of an article or two in this journal. We will see what can be put together.