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RealMarkDeneen's Achievements

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  1. The output tube of the preamp is working into a low pass filter where the total capacitance of the connecting cable is shunting the output of the tube. A typical rca cable might have 12pF/ft of capacitance between conductor and shield. Example 1. 8-foot cable @ 12pF/ft.. is 96pF. A 12AX7 in the BBX with zero feedback has an output impedance of say 75k ohms. So using that 96pF cable gives an upper bandwidth of a mere 22kHz. That's not going to give you sharp square waves. If I cut the capacitance down to 40pF I get 53kHz which is better. Example 2. Using a Peach in SuperLoZ mode, the output impedance is 600 ohms. So, I can connect 100 feet of cable @12pF/foot (total 1200pF), and I still get a whopping 220kHz bandwidth. THAT will have sharp square waves. Now you understand the reason for the Peach! Keep your cables short, and use low capacitance cable. Now, whether any of this is audible is a complicated matter and depends on many other variables. So, I'm not making a big deal out of it for SQ. But by measurements it is easily measurable. Cheers Travis, M
  2. Hi Dave, The higher the load resistance, the more the external cable capacitance will interfere with HF response. I like the line out to pass very sharp 10k square waves. Cheers, M
  3. 6H30: Using a 10K 2W plate resistor and 560 ohms cathode and 10k grid resistor you want 100V on pin 1 and 6 plates. Adjust the B+ feed resistor as needed. I don't recall the exact value but it's easy to adjust.
  4. Yeah. That would be Trevor Lees. He was a bright whippersnapper and took our phono section (which was pretty unique at the time) and stuffed it into old PAS3 chassis' without a line stage for maybe $250 bucks? Our Model 10 was selling for $895 at the time. He was a "local sensation" for a year or so. Nice guy. That era - 1970 - 1980- was, IMO, the golden Age of high-end audio in the Bay Area. It was a time of talent, ideas, and fun that is gone forever. I am so happy to have been a small part of that scene.
  5. My first whack at the audio business was Paragon Audio. I started it in 1974 with Bruce Moore (Audible Illusions). We made the Paragon Model 10, Model 12, and 12A as the big preamps, and then I made the System E as an Entry level preamp. The big ones were designed to compete with the mighty Audio Research SP3a. Yeah - wishful thinking, huh? Bruce left in 1975, and I kept it up until 1980 and sold out to ADC where I went and made the B-100, but decided Connecticut wasn't for me, and we moved back to Cali.
  6. Hi Travis, Hmmm....The most difficult was the ADC B-100. However, I haven't heard one since the CES show of 1981! It's overly complicated, but at the time I think it sounded better than the Paragon 12A. According to my current recollections, the Peach II is my "best work. " It is novel, well-built, sounds great, and is pretty reliable, especially after the low-voltage bridge mods. OTOH, the BBX was the most fun - had the killer phono stage and especially the early versions had a look that I really loved. This month is the 20th "birthday" of the BlueBerry. The original prototype chassis shown here.
  7. Hi Dave, Ironically, NOSVALVES just sent me the System E schematic last week. I had lost it for good! Here you go. Cheers Mark Paragon E actual 1.pdf Paragon E actual 2.pdf
  8. Yeah, I ran into that at the Grand Canyon gift shop a couple of years ago. No relation that I know of.
  9. The B100 was part of the ADC "designer series" for 1981 and that scribble is my signature. Yes, I told the guy I was Mark Deneen, the designer. He just didn't answer. Oh well.
  10. @NOSValves This guy hasn't answered any of my inquiries. Weird, isn't it? https://www.ebay.com/itm/154913813046
  11. Right..that makes sense. My memory ain't that great anymore.
  12. Not 100% sure, but I think I changed the input sensitivity to 2V and raised the input impedance to 56k or something like that. I wanted to be able to drive it with a BBX. The sonic change came from the faster OpAmp and boutique caps.
  13. Yeah, really raw beast! Like hand made sheet metal and P2P kind of beast. Somehow we made 100 of them! If I described how we made them you'd split a gut. But the 10 was what got the Cream of the Crop cover story in Sound Advice magazine. A week after that review came out I had HUNDREDS of letters/orders from around the globe--asia, europe, japan, etc. Only TWO units existed, and one was at the magazine! If I had been smart, I would have called the magazine and said, "Hey, it was just a prank." Cheers
  14. Well the only skeleton that hasn't come out of the closet now is the Paragon Model 10 which is to preamps what a Rat Rod is to a Foose hot rod.
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