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 Post subject: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Fri 20, 2018 8:39 pm 
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William Hampton Bresee While at Sylvania, Emporium, Pa. designed this meter shortly after WW2. A patent was issued to him likely for the radio frequency probe circuit. (unfortunately I never asked him about details of the patent). He told me Hugo Gernsback visited him at Sylvania to talk about the meter saying he too had a similar idea. In the 1990's dad restored and re calibrated his meter for my use. I have a notebook of all the repairs notes he made at the time. The r.f. probe has been missing a long time and I have yet to find a replacement. (I have found a NOS 1247 tube for the probe).
WHB was born in Gouvenour, NY. Feb. 28, 1920. He graduated from Clarkson college in 1942 and went to M.I.T. to work on radar during the war years. To Sylvania after the war, first at Emporium and later at Williamsport where he married and I was born. Since dads specialty was the vacuum tube transistor tech limited job choices. After Sylvania he worked for Westinghouse 1st in Bath,NY, then nearby Elmira Hts.. He then worked for Raytheon in Mass. on Missile guidance systems due to his security clearance from WW2. These systems used tubes as they are not subject to EMP radiation as are solid state devices. I remember when he was informed that the ww2 radar material was unclassified. His last job before retirement was with Sony (CRT's) in San Diego. He moved back to NYS (Johnson City) to be close to family. He lived into his 80's. His meter never had a serial # plate in back as did later meters. I got a type 134 meter on ebay s/n 2802 unrestored but also w/o the rf probe. I hope this is of interest to someone.

Al


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Fri 20, 2018 11:16 pm 
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Absolutely! Got pix?


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Sat 21, 2018 12:08 am 
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Interesting! It's color scheme seems to match the Sylvania 140 tube tester I have from the same time frame. Photos please?
Attachment:
Sylvania 140 Tube TesterS.JPG
Sylvania 140 Tube TesterS.JPG [ 188.96 KiB | Viewed 2126 times ]

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Sat 21, 2018 6:28 pm 
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Here are images of my dad's Polymeter and s/n 2802 (right).


Attachments:
rsz_polymeter.jpg
rsz_polymeter.jpg [ 105.74 KiB | Viewed 2072 times ]
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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Sun 22, 2018 6:35 am 
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They are beautiful instruments. Aside from the high-bandwidth RF probe, the Polymeter type 134 uses a sophisticated two-stage DC amplifier, unlike most VTVMs that use only a single differential pair stage. The Sylvania 221Z and 302 Polymeters also use the same circuit (and the same RF probe - you might be able to find one of the later models with an intact probe that should fit your 134). The first stage of the amplifier is a pair of cathode followers operated at a very low plate voltage (about 20 volts) to minimize grid current from gas, thus enabling a very high input impedance. The second stage is the classic VTVM differential pair.

The Polymeter type 134 first appeared in Radio News in an ad in the December 1946 issue:
https://www.americanradiohistory.com/hd ... e-0099.pdf

The 134 was replaced in the Sylvania test equipment line by the Polymeter type 221, introduced in the August 1949 issue of Radio News:
https://www.americanradiohistory.com/hd ... e-0106.pdf

The two-stage DC amp circuit in the Polymeter is similar if not identical to McMurdo Silver's VOMAX VTVM circuit he introduced in the July and August 1945 issues of QST magazine. The McMurdo Silver Company later introduced the production VOMAX with a nine page ad blitz in the February 1946 issue of Radio News. Silver's circuit was a genuine improvement that offered much higher input impedances than had been available before, so it's to your father's credit that he recognized its value and used the basic circuit in the Polymeter.

Hewlett Packard also copied McMurdo Silver's basic circuit topology in the HP 410A VTVM, with the modification of using a pair of pentodes in the second-stage differential pair rather than the usual twin-triode. I don't know when the 410A was introduced, but I believe it was much later than the VOMAX and the Polymeter.

Interestingly, while the HP 410B uses a two-stage DC amplifier, the circuit topology is reordered from the one used by the 410A and the Silver VOMAX and Sylvania Polymeter. Instead of a pair of cathode followers, the input stage is a dual-triode differential pair, with a very high resistance in the long-tail common cathode resistor and some degeneration from lower-value separate cathode resistors for each triode. The input stage appears to have a voltage gain of about 8. Like the McMurdo circuit, it is run with a low plate voltage of about 20 volts to minimize grid current from gas, so that a high grid resistance can be used. The second stage in the 410B is a pair of cathode followers, so the stage ordering is the inverse of the McMurdo circuit.

The General Radio 1800A also uses a two-stage DC amp, or at least a two-tube DC amp. It has the usual triode bridge pair as the input stage with cathode-metering, but instead of resistive cathode loads, it uses a pair of triodes operating as constant current sinks, one for each side of the input bridge! I guess the high impedance cathode loads give high gain, which is then stabilized by negative feedback. Hmm, now that I think about it, the two tubes are in cascode, except that the input is to the top tube in the cascode rather than the bottom.

The Acton Labs 815 also uses a two-stage DC amp, but I don't have the manual handy to report on the circuit similarities and differences with the other two-stage VTVMs.


I have a Polymeter 302 that's I've slowly been restoring. There are a few other folks here on ARF with Polymeters as well. I'm hoping to add a 134 and a 221 to my collection at some time in the future.

Image

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Sun 22, 2018 12:38 pm 
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I agree with Steve. The Sylvania Polymeters are particularly splendid VTVMs, in both electronic and aesthetic design.

The 134Z seems the same as the 134, but with the panel graphics changed to the triple green line border. Both have banana jacks for the test leads.

I am not sure of the difference between the 221 and 221Z. Both have a cabinet with rounded edges and corners, triple green line borders on the panel, and Amphenol microphone connectors for the test leads.

The 302 represented an entirely new aesthetic, more modern and streamlined.

The 303 was a simplified VTVM, without the R.F. probe.

If there is a source for the 1247 subminiature diode for the probe, I would be glad to hear of it.

It’s splendid to learn the identity of the designer of the Polymeter. Here’s the patent to which Mr Bresee referred:

https://patents.google.com/patent/US2511562A/


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jul Sun 22, 2018 9:32 pm 
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Thanks all for the info especially the patent reference, I was not able to find it before. I did see the 1940's mag. ads on cd copies of the magizines. I got the 1274 tube from "Vacuum Tubes Inc." 1080 Sligh Blvd, Orlando, Fl. 32806 www.vacuumtubesinc.com Feb. 2014 catalog. Catalog had 13 pages of tubes listed in order from 00A(ST) to ZM1030 (NIXIE), then a list of used tubes and a list of used antique used tubes, the last pages are for dial lamps,tube sockets, capacitors, and books. You will have to check what is now available.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Mon 03, 2018 12:36 pm 
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Anyone have the manual for the 134? I picked one up for a song, but no probes and no manual. I know the RF probe is impossible too....


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Mon 03, 2018 1:02 pm 
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<sigh> ... now I'm gonna have to go out and find one of these for the museum. It never ends........ :)

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Mon 03, 2018 2:24 pm 
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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Mon 03, 2018 10:27 pm 
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sfox7076 wrote:
Anyone have the manual for the 134? I picked one up for a song, but no probes and no manual. I know the RF probe is impossible too....

A schematic for the type 134 is available at pacifictv.ca:
http://pacifictv.ca/schematics/sylvania134.pdf

Vintage Manuals will sell you a paper copy of the manual:
http://www.vintagemanuals.com/manual/Sylvania/134

Sylvania's booklet "Servicing Radio and Television with a Vacuum Tube Voltmeter" is essentially the manual for the Polymeter type 221Z, which is similar to the 134 and so may be useful. It can be downloaded from archive.org:
https://ia600501.us.archive.org/8/items ... hAVtvm.pdf

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Mon 03, 2018 10:42 pm 
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Philip Colston wrote:
I am not sure of the difference between the 221 and 221Z. Both have a cabinet with rounded edges and corners, triple green line borders on the panel, and Amphenol microphone connectors for the test leads.

The May 1949 issue of "Sylvania News" introduced the Polymeter type 221. It can be downloaded from the americanradiohistory.com site:
https://www.americanradiohistory.com/Ar ... s-1949.pdf

The March 1951 issue of "Sylvania News" introduced the Polymeter type 221Z. It also can be downloaded from the americanradiohistory.com site:
https://www.americanradiohistory.com/Ar ... s-1951.pdf

The article on the 221Z compares it with the 221:
"Twelve new features and improvements have been incorporated into the electronic volt-ohm-current meter, making it even better than before for AM, FM, and TV servicing. The modified Polymeter, known as the 221Z, has four new meter features. In place of the red pilot light, an illuminated dial is provided. For easy reading, separate AC 3-volt scale is combined with others and offset scales are eliminated for overall meter face simplification. A new zero-center scale has been inserted beneath the other scales, to permit faster TV and FM discrimitator alignment.

"Changes in control arrangements facilitate easier and faster switching. These include a new selector switch sequence, and combination of line and range switches. Removal of the bright jeweled pilot light eliminates eye distraction.

"Threaded type panel connectors have been provided for all leads, including the RF probe, which means more positive contact and no accidental pull-outs. Shielded leads, in a harmonizing gray color, as well as heavier red and black DC and COMMON leads, give the Polymeter 221Z a better and richer appearance.

"An all-aluminum panel in a pearl-gray, mar-resistant crackle finish, with new black panel lettering, provides both a smarter appearance and easier reading."

The differences between the type 221 and the type 221Z are somewhat subtle, but should be readily recognizable now that Sylvania has pointed them out.

Edit: I corrected the links to the Sylvania News.

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Last edited by stevebyan on Sep Wed 05, 2018 1:11 pm, edited 1 time in total.

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Tue 04, 2018 1:46 pm 
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HP's 410A VTVM first appeared in their 1946 catalog. I imagine "all of the above" noted manufacturers produced military version VTVM's of various types for the war effort, and after the war it was just a matter of getting products available commercially again so they all came out right around the same time.

On the back of HP 410A’s there is “that plate” you see all too often on post-WWII items that reads “This apparatus uses inventions of United States patents licensed by Radio Corporation of America……” That should give everyone an idea as to the foundation of where the allowable copy-catting began ;) Sylvania set their sights on the service market, HP and GR lab/industry, and McMurdo aviation/defense.

-Mark-


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Tue 04, 2018 2:41 pm 
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https://www.americanradiohistory.com/Ar ... s-1946.pdf has some nice introductory remarks regarding the meter in the December issue. It has a very funny statement about not trying to replicate the RF meter. I figure one could do it with the appropriate signal diode, but that will take a lot more research on the 1247 tube and the circuit than I have currently done.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Tue 04, 2018 4:43 pm 
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Mark, thanks for the info on the date of introduction of the HP 410A.

sfox, thanks for the pointer to the Sylvania News article on the Polymeter type 134.

Al, I found an article co-authored by your dad, Mr. W. H. Bresee and a colleague of his, Mr. J. E. Snook, in the February 1955 issue of "Service" magazine, pages 42 and 43:
https://www.americanradiohistory.com/Ar ... 955-02.pdf
The article describes the circuitry of the Polymeter type 302, and describes the operation of Mr. Bresee's patented circuit for linearizing the 3 volt and 10 volt AC scales.

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Wed 05, 2018 4:55 am 
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Just FYI, the 134 schematic is wrong on portions of the range switch where the amp current connection is made (unlabeled, but second up from the bottom). It is marked in Megs. It should be ohms. The resistors in the unit from Continental make me unhappy as they haphazardly label the ohm value. One is labeled 16M for 16,000 ohms. One is labeled 32000. Just wish they were consistent.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Wed 05, 2018 1:23 pm 
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Somehow, I wasn’t aware that Sylvania News was available at the marvellous American Radio History archive web-site. Excellent finds, Steve—and especially that article by Mr Bresee in Service! I see that I shall have to find yet more Polymeters……..

SFox, just a clarification-- the introduction of the Polymeter is in the September issue of 1946, at the link you provided, though there are further mentions of the instrument in the December issue. Also, on page M38 of the latter issue, note the television set with the separate CRT unit on top—and even more “futuristic” than the later Philco Predicta models.

The Polymeters were very well thought-out, and seem to cross the divide between laboratory and service type VTVMs of their era.

I’ve always thought that illuminated meters are both useful and aesthetically splendid.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Thu 06, 2018 5:27 pm 
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Do any of you who have these Sylvania VTVM's have some tear-down photos you could share? I don't see much of anything in regards to the insides of these on the old inter-webs. To me, seeing the way something is put together and the components they used is every bit as interesting as the circuit itself.

-Mark-


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Thu 06, 2018 6:47 pm 
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My restoration of my 302 has been on hold for a couple of years. I do have a few photos of the tear-down. I'll try to find the time to put them up. One interesting point is that it used dogbone-style precision carbon film resistors. I don't remember the manufacturer. Many of them had drifted out of tolerance.

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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Sep Fri 07, 2018 12:07 am 
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I just started. Have odd pictures, not great ones. Much of the interior in mine is clean and looked original. That said, the range switch runs me in fits. The schematic shows one resistor, but usually the resistors are series pairs of carbon comps. Many appear to be continental carbon co. Resistors. These Continentals all show significant drift. A 320,000 ohm resistor reads 389k. Then some are labeled with the 0s. They label resistors with number not colored stripes. Most are labeled with an M for 1000. A 16M is 16,000 ohms. 32000, not 32M. It gets more annoying because the 10 ohm resistor is two 5.1 ohm series resistors with a 100 ohm resistor strapped across. That is only 9.25 ohms as measured. Not sure whether to shoot for 10 or 9.2 with replacements. Because it is on the ohm range, which has a 3k zero pot, I am sure anything close would be fine, but I do wish I knew whether the 100 ohm resistor was original. I cannot imagine it is. I will try to post pictures in the coming days.


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