KR PX-25: HEALTH HAZARD DO NOT READ
DR. GIZMO'S BIRTHDAY RITUAL
Because I entered the world in the month of November, every November I celebrate. For the last couple of years I have enjoyed the following ritual: I load my Klepper kayak and I paddle down to South America and up the Amazon River to enjoy the company of my friends, the Jivaro Indians, because I really like to hang out with their shamans and partake in their rituals.
As you know the Jivaro Indians use mind altering plants in their rituals, and last year I brought them one of my favorite mind altering substances pastrami sandwiches from Katz's Deli, on Houston Street, in New York City. Let me assure you that there is nothing more thrilling than sharing a deep psychodelic experience with a Jivaro shaman with a sour pickle and Dr. Brown's soda.
Knowing that I was returning I thought long and hard about what I could bring that could top the lean pastrami sandwich. Fortunately I was into deep exploration of my 4th Wave Modality SET amplifiers and
Maybe I should stop here, because my experience is that some of the advice and wisdom I share destabilizes musicmaniac's lives and this can cause chronic flatulence, insomnia, hiding in the potty, and severe eye twitch. The question you should ask yourself is "What is the limit of my musical ascension?", or to put it another way which is the question asked in the Daedalus and Icarus myth "How high can I fly, before I fall into the sea?".
I decided to bring my Jivaro shaman bros' some KR PX-25s, which are powerful mind altering gizmos. Of all of the DHTs that I use, these tubes are the closest thing I can remember to experiencing, thirty years ago, when (I am not sure about these facts because of subsequent brain damage) Felicity forced me to take my first tab of LSD in a meadow outside of Woodstock on a summer's day the feeling of the whole world coming together.
Humility is in order here because I don't have a clue why these tubes sound so unique, and I don't think Count Kron or anyone else does either. Of course the question is why haven't you heard about these tubes, which are modeled after a tube that was the equivalent of the "Western Electric 300B of Europe" in the 1930s?
The other question is why is this tube, the coolest looking of all modern DHTs never used by any American audio manufacturer?
These are the questions I asked as I loaded my 1,600 pounds of Tannoy speakers and 400 pounds of (4 channels) of amplification into my kayak, with my portable nuclear powered generator, and started to paddle towards South America. Fortunately for me, a pride of Music Mermaid were basking off the Stamford harbor and swam over and wanted to know what was going down, and I told them I was headed for the Amazon river. Seeing the KR PX-25 they asked if they could come along and agreed to do most of work. Way cool.
See what I mean about becoming destabilized trying to imagine Music Mermaid, towing your Klepper Kayak all the way to the deep recesses of the Amazon river, and then hanging out with you on your birthday while listening to the sound that comes from beyond the world..
Back to the PX 25. There is only one good, and really silly reason, why this tube isn't known and used and it is its 4 volt filaments. As you know the standard filament voltage for all 300B types is 5 volts, and for 2A3 types are 2.5 volts. So it appears that if you want to experience the KR PX-25 you have to design a special amplifier NOT. All that is needed is (almost) is an extra winding on the power transformer for 4 volts.
You might consider taking a 2A3 amplifier, which usually has a B+ voltage of 250 volts, and just hook up an outboard 4 volt filament, BUT and here is where this saga gets exciting .
Think of the PX-25 as a really exotic fruit that requires a special squeezing process to fully realize the unique flavor of its musical juice and by that I mean mysterious aural matrix, harmonic refinement, and its ability to deeply affect the limbic snake center of your being. My experiments with this tube indicates that, because of its unique electrical characteristics, it loves 350 volts, at 40 ma, (using 3.5 K Plitron transformers) and that means you have to have a power supply that has the right bias circuit, and voltage.
And this tube needs a totally righteous drive circuit for you to experience is tactile beaudacity; its ability to jump and gyrate with the music. I use Lundahl interstage transformers. If you are not using IT, be sure to use a driver stage that can swing big voltage and current. I am not going to repeat again the importance of a complete separate and regulated power supply for the front end and output stage but there is no other way to experience this tube's capacity to dive deep into music shadows.
For fans of the 2A3, this tube is where you want to ascend to, and it is more powerful, but it does not have the testicularity, in the lower register, that can be achieved with the best new steroid enhanced 300Bs like the KR 300BXL.
MY DEMONSTRATION FOR THE JIVAROS
Talk about a party: The Jivaros had never seen Music Mermaid before, and they just swam around the landing of the village and sang some of the best Carole King, Janis Joplin, and Tina Turner songs. In only a few short hours I had the system hooked up and working and here is where the Jivaros went bonkers
Using the Marchand tube crossover I connected the KRPX-25 amp directly to the tweeters, and the KR300BXL amps directly to the woofers all connected to my bevy of tube regulated power supplies and we rocked to early Cat Stevens, and Leon Russell. How high did we get? The next morning I discovered that my Nike sneakers were filled with Moon dust and I had fish scales on my chin!What should your response be to this saga? Pester the Hell out of Ron Welborne to make an amplifier for these tubes. How tough would it be for him to modify his 2A3 amp? About as difficult as opening a can of Bud and then you could experience what it is like to hang out with Music Mermaid and Jivaro Indians on the moon.
e-mail Dr. Harvey "Gizmo" Rosenberg: firstname.lastname@example.org
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