From: info@turneraudio.com.au   
      
   On Wednesday, October 28, 2015 at 2:37:11 AM UTC-4, John L Stewart wrote:    
   > Pink Floyd    
   >    
      
   A few, those of us that still dabble anyway. The long, cold winter is about to   
   begin and I have half-a-dozen projects in the queue - mostly restorations.    
      
      
   Peter Wieck    
   Melrose Park, PA   
      
   Summer has just started here, with high probability we'll have a record number   
   of days over 35C. ( 95F )   
      
   It won't be because every dude has an extra beer, and dozes off, leaving their   
   tube amp on all night.   
      
   Anyway, I'm totally re-building an RF gene with tubes which I first made in   
   1997. This time I've armed my brain with Secret Knowledge known only by well   
   paid HP boffins of 1955 who designed the HP606A RF gene. I'm at my limit, and   
   I won't be trying to    
   make an oscilloscope like the Tektronics 55 which starred in a video I watched   
   recently. That Beast was reviewed by an oscilloscope collector, the truly   
   compulsive collector of insanely complex old junk. All the other gathered   
   oscilloscopes which sat    
   around watching while this bloke told us all about the 55 all looked insanely   
   jealous 'cos they were not getting the attention. Anyway, bloke rattled on and   
   on and about the 110 tubes it had in two large boxes. He finally turned the   
   darn Old Girl 55 ON,    
   and it all came to life OK, and this sort of thing is the American Solution to   
   Lonely Farnarkling in the Shed during your freezing winters which de-nuggets   
   brass monkeys! Once the 55 runs, its T-shirt time while its -20C outside.   
   Amazing what still lurks    
   in countless basements and garages right across the USA. You can get every   
   thing you want at the E lek Tronic resto ront.   
      
   My humble little gadget sure has tubes, but only about 8, plus a few bjts,   
   because I'mm tryna combine benefits of tuned circuits with cathode modulation   
   of a PP pair of 6EJ7 - or maybe EL86, and I should get a BD139 to do what one   
   of a few 6B4 do in 606A,   
    hopefully better, less THD in envelope shape.    
      
   I dunno how they'd do AM now, lots and lots and lots of utterly    
   ncomprehensible didgets & bizibots I guess.    
      
   I tried untuned circuitry with all SS, and frankly, the outcome compared to   
   HP606A was quite appalling. Bandwidth stopped at 4MHz, and AM waves looked   
   horrid above 2MHz, and probably, BF469 are NOT the ideal device to use for the   
   modulator pair. NFB    
   loops just would not work. I know - you don't have yell "Ain't ya heard about   
   the latest HP function gene?" Much about HP I do like, but hasn't it all gone   
   Chinese? Agilent stuff seems to have gone to China. I bought a new 117 Fluke   
   DMM, better than    
   oldun I had since '93. BUT, there's a bother with Vac reading, reads no lower   
   than 22mV, and in mV range no lower than 4mV. BUT, another I tried at same   
   shop reads down to zero with leads shorted OK. To get that Fluke fixed, its a   
   pile of trouble I guess,   
    or Sum Wonk in the Chines factory forgot to calibrate a pot properly.   
   so.........     I was asked, "what do you think about Chinese Quality Control?"   
   and I answered "I was told they were to begin trials with that novel concept   
   during next five year plan".    
      
   Oh, and if there's a whiff of Vdc while tryna read mVac with 117, she won't   
   read properly, so I have to use an adapter I made for putting in 0.33uF and   
   330k to block the Vdc, then she's OK. Oldun read Vac OK regardless of presence   
   of Vdc. Musta been a    
   male voltmeter.    
      
   The Whirled won't disintegrate because of such trifling complaints.....   
      
   Patrick Turner.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)