[Amps] Source of Mica Caps?

[Carl]

> Carl, if semi  floating the grids with caps..on a GG triode is such a 
> wonderful idea, then how come you will
> NEVER see it done with tubes like  8877,  3CX-3000A7,  3CX-6000A7 and 
> YC-156, YC-172,  GS-35B ??
> You don’t even require a suppressor with the above tubes.

** Totally different tube geometry Jim, you should be able to understand 
that. Altho many 8877 and 3X3 amps use suppressors to be safe.

No trade secret hush-hush  top secret KM1H designed
> suppressors required>

** No secret, anybody with even a basic understanding of amp design could 
build them.


> IMO, you gotta be nuts to use grid caps + chokes on any 3-500Z amp.

** OH? So you and a few other glorified techs want to argue with experienced 
engineers that designed the amps? I give them the benefit of the doubt 
considering the number of Heath, Drake, KW, and other amps out there that 
far exceed the very little minority that believe "if it aint broke dont fix 
it"


   Besides, with the grids bonded to chassis
> with wide cu strap on any   SB-220, SB-221,  TL-922, L4B, henry amp etc, 
> you can now stuff  4-400A/B/C  tubes in there
> and they run just fine.


** Thats a quick change if 3-500's become unobtanium. With the lower gain 
the 4-25/400 tubes are very stable.


   The grid chokes on any L4B amp is not gonna make for a good grid fuse any 
time soon, it can’t.
> The grid choke on a L4B is only .9 ohm  vs the 25 ohms on a SB-220.


** This thread is about the SB-220. Plus the L-4b is a more stable 
construction.


>
> A  simple, fast HV fuse wired in front of a 50 ohm glitch resistor..and 
> both wired into the B+  takes care of any anode to grid flashovers,
> blows open in less than 2 msecs.   50 ohm glitch R  limits the peak fault 
> current, and the HV fuse interrupts the peak fault current.
>
> 2nd fast HV fuse, wired between either sec of plate xfmr and FWB, protects 
> the FWB + xfmr, in cases where a short occurs  prior to the glitch 
> resistor.
>
> A simple  rear mount 3agc fuse holder, bayonet type, + fast grid fuse, 
> makes grid protection easy on any directly heated,
> thoriated tungsten tube.  ( wired between  chassis  + neg terminal of the 
> grid meter..or grid shunt).


** M.I.C.K.E.Y.  M.O.U.S.E.   OK on one of  your illegal amps.


> With 8877, YC-156, and any other indirectly heated, oxide typ tube, 
> electronic protection is required.
>


** It has also been used with 3-500 amps.


> For a HB 6m amp, even if I had a case load of new chinese 572B tubes.... I 
> still would not use em.   Sure they will work, but are a poor
> choice for a 6m  GG amp.   A  SINGLE  GS35B  on 6m, will easily run 
> quadruple the power of one of your SB-200  6m  conversions......and no 
> suppressor
> required on the GS-35B !

**  More illegal power BS from the Mouth of The North.

   This has got nothing to do with  running high power with bigger metal 
tubes either.

** BS, its all about you.

 It’s a simple case of using the right tube
> for the job.  The SB-200 came out in 1964.    It’s now  2013, get with the 
> program.

** A.  They work.
     B. There are thousands of cheap SB-200's with all the hard work done.
     C. Not everybody has several thousand $$$ to play with.
      D. 600W is all it takes most of the time and most ops arent obsessed 
about being #1.
      E.  They likely have better IMD than an overstressed dirty IMD Ruskie 
tube.
      F. At one time the SB-220 was a $300-400 amp but all the new ex CB no 
coders ruined that market. Those on a budget go for the SB-200.

** My own 6M amp was built in 1963 and is all Ive needed. A converted 
NCL-2000 engineering prototype that I did in 65. I paid $20 for the amp and 
about the same to convert.

> later.... Jim   VE7RF

** I suspect most on this forum prefer simple and legal power, not some 
freak show ego trip.

Carl
KM1H