• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

12B4 Line Stage + Phono Option

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To the 12B4 Line Stage Followers,

I am finally recovering from my eye surgery and back on the horse. My head injury last spring caused my retina to tear and I've been out of commission for a while.

Anyway, I'm continuing on the 12B4 Kit project and adding a phono option. I've been scouring sources around the world and have purchased a good stock of RIAA equalizing resistors. For superb phono--you need really good OIP capacitors, and I now have them in abundance. Some are from the old Tektronics Select Oscope stock, others are from Russia military surplus.

There were a number of issues to solve in keeping the power supply compatible with both the 12B4 and 12AX7 stages. I'll start posting results as I'm just about ready to begin testing.

On the other issue--the estate sale tubes--I'm still waiting. I've submitted a blind bid and am hoping. If that doesn't work out, I now have a partnership with a local tube dealer who has about 1/2 million NOS audio tubes. Either way--I have an excellent source of NOS tubes for the amplifier kits.

Other news-the high end case design is also proceeding. In a few weeks I'll have some designs to post for comment. I believe I have come up with a method that will greatly simplify construction--and maximize beauty.

Cheers to all.
 
I won the tube auction

Great News!

I won the estate sale auction for tubes! It took three trucks and most of a day to move it to my house.

The lot was ultra clean--no TV tubes, all radio and audio. What a find! I now have stock to run the kit business with NOS tubes for a looong time.

Found a 274A in the stash along with quad of Genolex KT-66 and KT-88, not to mention boxes and boxes of other sweet tubes.

Probably sell the 274A to a collector in Japan.
 
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