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The Kid

    48°21'48N, 107°52'48W±500mi.
HP 200CD Valve (tube!!) oscillator problems?
« Reply #20 on: July 08, 2004, 03:51:32 PM »
"H and P were not that savvy at transformer design."

Maybe not, but BOTH transformers (T1 PN# 200CD-9, HF & T2 PN# 9120-0016, LF) are wired to the range switch(s).  I think what you're trying to say is, the LF & HF are combined into one output, as that's how the switches are wired.  Each transformer has it's own EL-86.
I know enough to be dangerous


NewYorkDave

    New York (Hudson Valley)
HP 200CD Valve (tube!!) oscillator problems?
« Reply #21 on: July 08, 2004, 04:26:25 PM »
I love my old HP tube oscillator... I think mine's a 200AB, because it covers the audio range only, but I don't have it handy at the moment to check.

PRR mentioned calibrated attenuator sets and "gain sets." Maybe I'm an anachronism, but I use 'em. I've got two Gates stereo gain sets, as well as some H-P calibrated 600-ohm attenuator sets. I scanned the manual for the Gates gain set, which can be found here. The circuit could be DIY'd if one were sufficiently motivated. Probably easier just to hunt around for a used one, though. Gain sets are, or at least were, used by every broadcast station for their annual FCC-mandated "proofs" (proof-of-performance tests). Calibrated attenuator sets come up often on eBay. These sell for pretty cheap, usually.

MikoKensington

    Detroit
HP 200CD Valve (tube!!) oscillator problems?
« Reply #22 on: July 08, 2004, 05:45:25 PM »
I have an AB as well.  A nice 4 rack space unit, it is.  I wish I had a use for it.   :roll:

fum

    Seattle, USA
HP 200CD Valve (tube!!) oscillator problems?
« Reply #23 on: November 19, 2005, 01:38:22 AM »
(resurrecting thread :grin: )

I have a 200CD as well.  

A question(this hit me while driving in the car today),  this oscillator is capable of crankin many volts (24V AC!!).  I can't think of anything I do with audio at present that would need to go so hi.  

What were they building these things to test?

Regards

ju

bcarso

    San Fernando Valley, Los Angeles
HP 200CD Valve (tube!!) oscillator problems?
« Reply #24 on: November 19, 2005, 03:45:58 PM »
Well---you could drive a single 6AS7 on the bench to a useful output directly if you liked.  And cooking resistors, as PRR mentioned.

I have a 200CD sitting on the floor at the moment, but it's reassuring to think it's there for an emergency  :green:  or when I need MORE COWBELL!!  errr... I mean voltage.


 

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