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The HP Original for sale

Started by bitrex July 2, 2017
HP 200C Wein Bridge oscillator up for sale on eBay. $125.

<http://www.ebay.com/itm/Vintage-Hewlett-Packard-HP-200C-Vacuum-Tube-Audio-Oscillator-/361862146302?hash=item5440aa28fe:g:ROkAAOSw2xRYXvsQ>

"Thank You For Looking At Are Item"

The 200C isn't the original 1939 model. It was the last tube instrument HP sold (CRTs and PMTs apart) and was in their 1985 catalogue. (Yes, I have one.) ;)

Cheers

Phil Hobbs
On 07/02/2017 06:15 PM, pcdhobbs@gmail.com wrote:
> The 200C isn't the original 1939 model. It was the last tube instrument HP sold (CRTs and PMTs apart) and was in their 1985 catalogue. (Yes, I have one.) ;) > > Cheers > > Phil Hobbs >
Wow, that late? I'm trying to think of other 1930s era industrial designs that had such a long life cycle. GG1 locomotives? Iowa class battleships? GM straight six?
On Sun, 2 Jul 2017 21:46:43 -0400, bitrex
<bitrex@de.lete.earthlink.net> wrote:

>On 07/02/2017 06:15 PM, pcdhobbs@gmail.com wrote: >> The 200C isn't the original 1939 model. It was the last tube instrument HP sold (CRTs and PMTs apart) and was in their 1985 catalogue. (Yes, I have one.) ;) >> >> Cheers >> >> Phil Hobbs >> > >Wow, that late? I'm trying to think of other 1930s era industrial >designs that had such a long life cycle. GG1 locomotives? Iowa class >battleships? GM straight six?
Not '30s, rather '40s, but B52s are still flying and from what I gather, they'll be flying another 30 years and perhaps longer. There are three generations of pilots who have flown the same bird.
pcdh...@gmail.com wrote:

---------------------------

> The 200C isn't the original 1939 model.
** That was the 200A - see full manual with schem: http://www.hparchive.com/Manuals/HP-200A-Manual-1951.pdf FYI: Since my mid teens, I have owned a fairly similar oscillator - all valve using a large, dual tuning gang from an old radio. A 30:1 reduction, worm drive is fitted to the gang which is fitted inside its own steel box. Means the unit works perfectly with the cover off. A pair of 6AM6s (aka EF91s) operating as triodes form the oscillator, amplitude is stabilised by an R53 glass bead thermistor. A single 6BQ5 is used as a cathode follower for low Z output. Has three ranges, covering from 18Hz to 22kHz. The original metalwork and basic circuit was built by staff at the Kodak factory at Coburg in Melbourne as a low frequency oscillator for motor drive, it originally used a large, dual gang WW pot. I fitted the tuning gang and other bits to make it a general purpose audio oscillator including square waves using a 12AT7 wired as a Schmitt trigger. I still have it and gave at a major overhaul a couple of years back. .... Phil
 bitrex wrote:

-----------------


> > > Wow, that late? I'm trying to think of other 1930s era industrial > designs that had such a long life cycle. GG1 locomotives? Iowa class > battleships? GM straight six? >
** Well there is the DC3 with many flying examples. But the 6L6 beam tube takes the prize since it has *never* been out of mass production since 1936. ..... Phil
On 03/07/17 02:46, bitrex wrote:
> On 07/02/2017 06:15 PM, pcdhobbs@gmail.com wrote: >> The 200C isn't the original 1939 model. It was the last tube instrument HP >> sold (CRTs and PMTs apart) and was in their 1985 catalogue. (Yes, I have one.) ;) >> >> Cheers >> >> Phil Hobbs >> > > Wow, that late? I'm trying to think of other 1930s era industrial designs that > had such a long life cycle. GG1 locomotives? Iowa class battleships? GM straight > six?
B52s have an expected ~90 year product lifetime, 1950s to 2040s.
On 3.7.17 04:46, bitrex wrote:
> On 07/02/2017 06:15 PM, pcdhobbs@gmail.com wrote: >> The 200C isn't the original 1939 model. It was the last tube >> instrument HP sold (CRTs and PMTs apart) and was in their 1985 >> catalogue. (Yes, I have one.) ;) >> >> Cheers >> >> Phil Hobbs >> > > Wow, that late? I'm trying to think of other 1930s era industrial > designs that had such a long life cycle. GG1 locomotives? Iowa class > battleships? GM straight six?
DC3 / C47 from Douglas Aircraft. -- -TV
On 07/02/2017 10:23 PM, Phil Allison wrote:
> pcdh...@gmail.com wrote: > > --------------------------- > >> The 200C isn't the original 1939 model. > > ** That was the 200A - see full manual with schem: > > http://www.hparchive.com/Manuals/HP-200A-Manual-1951.pdf > > > FYI: > > Since my mid teens, I have owned a fairly similar oscillator - all valve using a large, dual tuning gang from an old radio. > > A 30:1 reduction, worm drive is fitted to the gang which is fitted inside its own steel box. Means the unit works perfectly with the cover off. > > A pair of 6AM6s (aka EF91s) operating as triodes form the oscillator, amplitude is stabilised by an R53 glass bead thermistor. A single 6BQ5 is used as a cathode follower for low Z output. > > Has three ranges, covering from 18Hz to 22kHz. > > The original metalwork and basic circuit was built by staff at the Kodak factory at Coburg in Melbourne as a low frequency oscillator for motor drive, it originally used a large, dual gang WW pot.
The manual mentions a rackmount model - I'd never heard of that! Google only turns up an image of a rackmount "200CDR" which looks to be a later product with a significantly different design
> I fitted the tuning gang and other bits to make it a general purpose audio oscillator including square waves using a 12AT7 wired as a Schmitt trigger. > > I still have it and gave at a major overhaul a couple of years back. > > > .... Phil >
Tangentially related - the audio sine wave oscillator I've been using for several years is a solid state box labeled "LofTech"; manufactured by "Phoenix Audio Labs, Manchester, CT". It's mostly full of LM13600s and TL074s with date codes from the middle of 1986. I don't have a THD analyzer so I can't say what its specs are now in that regard; visually at least the sines it puts out look math textbook perfect on a scope. The brochure claims a maximum THD of 0.5% Unfortunately frequency stability isn't good - it's very drifty with time and temperature; sometimes 3-5 Hz up and down over time just sitting in a shop at room temperature, which is annoying. The brochure scan online doesn't say anything about drift specs so I don't know if that's normal for the product's design or if it should be serviced. I managed to find a schematic: <http://www.ka-electronics.com/images/jpg/Loftec_TS1.jpg>
On Sun, 02 Jul 2017 15:15:25 -0700, pcdhobbs wrote:

> The 200C isn't the original 1939 model. It was the last tube instrument > HP sold (CRTs and PMTs apart) and was in their 1985 catalogue. (Yes, I > have one.) ;)
And I've probably got one, too. :P