Super DX-5
1930
Norden-Hauck, Inc.
Engineers
NW Corner of Delewar Ave. and South St.,
Philadelphia, Pennsylvania, USA

    The Super DX-5 was Norden-Hauck's answer to short wave listening in 1930. It was designed to be a fully, self contained, SW receiver with band switching capabilities by means of plug in coils. It's a Screen Grid TRF/Regenerative receiver that was designed to compete against the Pilot "Super Wasp", the Silver Marshall "Around the World Wide 4", the National SW-1 and SW-2 sets, the ICA "Challenger" and other shortwave receivers of that time. The front controls consist of a vertical tuning dial, antenna control, RF. and Det. trimmers, and a regeneration control. The regeneration control acts as the volume control but can also act as the BFO for listening to SSB when it's turned high enough to allow the set to go into regeneration. When listening to SSB, the antenna control can be used as the volume control. The RF. and Det. trimmers can be used to fine tune the desired frequency for the best SSB audio. On the bottom cover plate is stamped with the serial number A113. It was a common practice to start a serial number with 100 or 1000 in order to give a false indication of greater production then what there actually was. If this is the case with this set, and I believe it is, then that would make this the 13th receiver that Norden-Hauck made. It's believed that these receivers were only made during the first half of 1930.
    I acquired this receiver in August 2013 by trading a McMurdo Silver 18 inch concert speaker for it. I believe this receiver is one of only three receivers that are known to exist.

Tube Line Up:
CeCo AC Pentode.....RF Amplifier
27.....Detector
27.....Preamplifier
45 X 2.....Audio Output
80.....Rectifier

Power Source:
AC...120 Volts

Frequency Range:
LW.....100 kHz - 550 kHz
BC.....550 - 700 kHz / 700 kHz - 1600 kHz
SW1.....1.5 MHz - 3 MHz
SW2.....7 MHz -15 MHz
SW3.....3 MHz - 7 MHz
SW4.....15 MHz - 25 MHz

Schematic

Dimensions:
Height.....9 inches
Width.....19 inches
Depth.....10 inches

Address location on Google Map.

    This is the underside view of the chassis prior to restoration. Upon close examination, there was considerable evidence that this receiver had been serviced before, possibly during the 1930s. There was a number of resistors and wires that were poorly soldered in place, and in some examples, there were connections that were totally void of any solder. One of the Grey and white "dogbone" resistors that fed the B+ voltage to the 27 audio tube was supposed to have a value of 12K ohms but it actually measured 120K ohms. This means that , at some point in time, there was a production run of 120K ohm resistors which were mislabeled as 12K ohm resistors and one of these resistors made it's way into the production of this particular receiver, thus, drastically reducing the audio quality of the first audio stage. It's hard to say if any of the other DX-5 receivers were affected in this way but it's quite possible. There's also the possibility that the 120K ohm resistor was the correct one to use and the schematic diagram is wrong. Either way, in the restoration of this receiver, I decided to replace the 120K ohm resistor with a NTE brand 12K ohm 2 watt metal film resistor. In the overall  restoration of this receiver, half of the resistors were bypassed by 2 watt metal film resistors and all of the paper capacitors were bypassed by modern NTE filter capacitors and moden bypass capacitors.

    Below is the set of coils that came with my DX-5. The three large coil sets make up the standard set of coils that were to accompany every DX-5 that was originally sold. Each coil set is numbered on the bottom of their bases and their designated tuning ranges are as follows:

Coils #1.....7 MHz to 15 MHz
Coils #2.....3 MHz to 7 MHz
Coils #3.....1.5 MHz to 3 MHz

    The smaller coil is one of a set of coils (it's companion coil is currently missing) that was designed to tune 15 MHz and above. It was an additional set of coils that was to be purchased separately.

Coils #0.....15 MHz to 25 MHz

    There was a set of coils ,to be purchased seperatly, which covered the BC and LW band. The BC coils could change thier tuning ranges by means of a switch and a capacitor which were attached to them.

Coils #4.....550 to 700 kHz / 700 kHz to 1600 kHz
Coils #5.....100 kHz to 550 kHz

Coils #0.....15 MHz to 25 MHz

Coil Form.....Length 3 inches / Width 1.5 inches
Primary Coil......2.75 turns of 16 gauge silk covered solid core wire.
Regenerative Coil..... 4 turns of 30 gauge silk covered solid core wire.

    I only have this one coil of what's supposed to be a matched set of coils. I plan of making a complete set of reproduction coils for this frequency range.

Coils #1.....7 MHz to 15 MHz

Coil Form.....Length 3 inches / Width 2 inches
Primary Coil......5 turns of 18 gauge silk covered solid core wire.
Regenerative Coil..... 6 turns of 30 gauge silk covered solid core wire.

Coils #2.....3 MHz to 7 MHz 

Coil Form.....Length 3 inches / Width 2 inches
Primary Coil......12 turns of 18 gauge silk covered solid core wire.
Regenerative Coil..... 5 turns of 30 gauge silk covered solid core wire.

Coils #3.....1.5 MHz to 3 MHz

Coil Form.....Length 3 inches / Width 2 inches
Primary Coil......28 turns of 20 gauge silk covered solid core wire.
Regenerative Coil..... 6 turns of 30 gauge silk covered solid core wire.

Coils #4.....540 to 700 kHz / 700kHz to 1600 kHz

Coil Form.....Length 3 inches / Width 1.5 inches
Primary Coil......64 turns of 22 gauge silk covered solid core wire.
Regenerative Coil..... 6 turns of 30 gauge silk covered solid core wire.

    Because my receiver never came with a set of #4 BC coils, I had to reproduce them. The bases were made from a salvaged 1920s bakelite radio panel that I acquired from fellow collector Alan Douglas. Their surfaces were lightly scraped with fine sandpaper in order to mach the dull matte finish that the original coil bases had. The standoffs were made from two plastic 1/2 inch standoffs which I glued together, cut down to 3/4 inches in length, sanded and painted matte black to match the look and texture of the original standoffs.The banana plugs were purchased  from MAI/Prime Parts of Indianapolis, the Garolite coil forms were purchased from the McMaster-Carr Supply Company of Elmhurst, Illinois, the 22 gauge vintage silk covered wire was purchased on Ebay, and the 30 gauge silk covered wire was salvaged from a salvaged 1930s radio IF coil. Spegettie tubing was used to cover the wire leads from the coil to the contacts.

    I made this coil rack in a style that I thought would closly match the styling of the receiver. The base is made of Ash, which was painted black, and the panel was made of aluminum which was bead blasted to match the aluminum surface of the receiver.

    The frequency range ID plates were engraved at a local trophy shop. They had a plastic that had a surface that exactly matched that of bakelite. Each coil has it's own socket  which makes coil removel and insertion easy.

Citizens Radio & Call Book Magazine and Technical Review
Winter 1930, Page 151

The above ad shows the DX-5's early design. Only one RF trimmer is featured and it's located above the dial. This design lasted only a few months in 1930 before the design was changed to feature two RF trimmers which are located below the dial.

Citizens Radio & Call Book Magazine
Winter 1930, Page 100

Radio News, December 1930
Page 559

Norden Hauck DX5 Designed For Quiet AC Operation

    Following is a description of the Super DX-5 receiver, a recent commercial development, by Norden Hauck, Inc., giving the points of particular interest to the short leave enthusiast. This receiver was designed with the following points in mind: complete a.c. operation without hum, increased sensitivity and selectivity, ease of control and ability to hold calibration, good tone quality and sufficient power output, and ability to cover a wide frequency range. The completed set has fulfilled these points with a high degree of satisfaction.
    The accompanying photograph shows the type of construction employed resulting in an efficient set that is fairly compact (9 inches high, 18 inches long, 10 inches deep), and one that has an appearance of which the owner may be justly proud.
    A power transformer, with three 2.5 volt secondaries, has resulted in the suppression of those tunable hums that are encountered on the higher frequencies. Each secondary has a 20 ohm center tap resistance shunted across it with the centertap connected to ground. These resistances are located right at the respective sockets and the grounds are made to the common point for that stage. Grid and plate wires do not run near the resistance, hence no pick-up of hum.

AVOIDING PICKUP
    The antennae binding post is on the left side of the set, near the front, which position was chosen to avoid coupling between the antennae lead-in and the power supply. One side of the line is grounded through ˝ microfarad condenser. Inserting the power supply plug in the light socket so that the ungrounded side of' the line is connected to this condenser usually results in the quietest operation. A type 80 tube is used as rectifier for the plate supply. The speaker is connected by plugging into a new type of socket similar to a UY socket but with an extra prong which controls a switch closing the field terminal contacts when the speaker is removed. In this set the switch is so connected that when the speaker is removed a 500 ohm resistance is connected in place of the field winding resulting in no change in voltage and eliminating the possibility of damaging the set by high voltage. The set may also be operated with a magnetic speaker with the plug removed with a slight increase in hum. It is intended however that a choke coil be plugged in when the dynamic speaker is not used.

USING RF PENTODE
    The use of a tuned radio frequency incorporating, a pentode tube provides a marked increase in sensitivity and selectivity. At frequencies lower than 10,000 kilocycles the gain obtained from a pentode tube was noticeably greater than that obtained from a screen grid lobe. The extra gain is not obtained from the pentode tube unless the tube is worked at its maximum plate potential, that is 250 volts. When the pentode is worked at l80 volts plate potential the gain over a screen grid tube is hardly worth while. The greatest gain was obtained when the detector coil was used as a tuned plate impedance.

NO BODY CAPACITY
    The design of the Super DX-5 is such that there is no hand capacity effect oil even the highest frequencies. This has been accomplished by complete shielding and by doable shielding between the contents and the front panel. As can be observed in the photograph there is an inner shield upon which the antenna coupling condenser, the radio frequency compensating condenser, the detector trimmer condenser and the regeneration condenser are mounted. These controls are grounded on this shield, except for the antenna condenser, and are insulated from the front shield. This prevents all currents from flossing in the front shield. The two main tuning condensers are mounted on the same shaft and mounted in the set in a vertical position with a knurled aluminum drum dial projecting through the panel. The vertical mounting results in a minimum of friction and equal pressure on the bearings giving smooth and noiseless operation coupled with great ease of adjustment. An illuminated celluloid scale enables accurate logging and serves as a pilot light. The radio frequency compensating condenser provides a ready means for lining up the radio frequency stage and compensating for changes in capacity produced by variation of the antennae coupling condenser.
    The detector trimmer condenser provides a fine tuning adjustment equivalent in 1.80 degrees adjustment to from one to three degrees on the main tuning dial.
    Variation in the radio frequency compensating condenser has only a slight effect upon the tuning of the detector stage, not enough to lose the beat note of a signal, and the detector trimmer condenser provides a ready means to bring the detector in line again. For amateur band reception the main tuning control can be set at predetermined points and all the tuning done with the lower controls. The regeneration control is noiseless and very smooth in operation and has only a slight effect on tuning so that when reduced to stop oscillation for reception of a modulated signal the readjustment is tuning will never be greater than a slight change of the detector trimmer condenser and usually none at all is needed.

CHART FURNISHED
    An individual calibration chart is furnished for each set and when the tubes are supplied this calibration is made with the tubes that are to be used. An accuracy of 1 per cent or better is obtained and due to the rigid construction of coils and set there is very little change in use. This tuning chart is of great advantage to the newcomer to the short wave field as it enables him to locate the stations desired or identify the stations heard in spite of the tremendous span of frequencies covered.

TONE QUALITY
    No sacrifice in tone quality was made in lieu of more difficult means of reducing hum. Low ratio high quality audio transformers are used with two type 45 tubes and a dynamic speaker enabling an output to be obtained which in audio range and undistorted power equals the standard set by the finest broadcast receivers. There are plenty of short wave phone signals oil the air which with an efficient set will supply enough power to load up push pull 45's. A headphone jack is provided which taps in the plate of the first audio stage, cutting out the loudspeaker, or if desired phones may be connected to the magnetic speaker terminals.
    Standard equipment includes three sets of coils, six coils all. which cover a range of from 1500 to 15,000 kilocycles with generous overlap between coils. Extra coils can be obtained to cover from 15,000 to 25,000 kilocycles. For reception in the ordinary broadcast band coils may be obtained which cover from 540 to 700 to 1600 kilocycles in two steps by means of a switch provided on the base of the coil which cuts in an auxiliary condenser for the lower frequencies. On special order coils can be provided to cover from 100 to 550 kilocycles, two sets of coils being used. When operating on frequencies lower than 550 kilocycles an adjustable tickler is provided on the coil and a .005 fixed condenser is shunted across the regeneration condenser.

Citizens Radio Call Book and Technical Review
September 1930
Pages 52 and 108

Citizens Radio Call Book and Technical Review, September 1930
Page 52

Citizens Radio Call Book and Technical Review, September 1930
Page 52

These photos of an origional brochure were taken off of an Ebay auction.

2014 ARCI "Radiofest" Radio Contest Entry - Operating
There is an extra set of BC coils plugged in the receiver.

Norden-Hauck Super DX-5
One of a Kind
BY ROBERT E. GRINDER
Robert Grinder shares with R.R.C. readers the tale of collector Les Rayner's youthful infatuation with the Norden-Hauck Super DX-5 shortwave receiver, and of Rayner's search for this one-of-a-kind radio. This is a story with a happy ending.
An earlier version of this paper appeared in the "California Antique Radio Gazette," Volume 16, May 1991, pp 12-15. (Editor)


    The saga of the Norden-Hauck Super DX-5 - a presuperheterodyne, shortwave receiver - is one of the more curious in the annals of radio manufacturing. This set was marketed but never manufactured and, apparently, only one prototypical model was constructed. On the one hand, Norden-Hauck engineers regarded the Super DX-5 initially as an extraordinary technological marvel. In 1930, they proudly proclaimed it to be the most advanced shortwave receiver ever! However, the force of their commitment and the strength of their enthusiasm succumbed eventually to anguish, disappointment, and hand-wringing. After declaring in national publications that the Super DX-5 would be forthcoming soon, NordenHauck engineers recognized that they had overlooked insurmountable flaws in its design. Consequently, the Super DX-5 was never manufactured. On the other hand, the engineers had produced at least one prototypical model of it, which is owned by Les Rayner of Scottsdale, Arizona.
    Les Rayner is well known among collectors of premier vintage radios. His resources, perseverance, and good luck have enabled him to assemble an array of rare, relatively early shortwave receivers. He has possessed, in addition to the NordenHauck Super DX-5, a Pilot Super Wasp, an ICA Conqueror, a Hammarlund Comet-Pro, a Paragon RA-10/DA-2, a Grebe CR-18 Special, a Silver-Marshall Around the World Four, a DeForest Radiophone, a Leutz shortwave receiver, and, respectively, a National SW-2, SW-3, SW-4, and SW-5.
Les has special affection for the Norden-Hauck Super DX-5. The hyperbole associated with marketing this receiver in the early 1930s left him with a lifelong ambition to acquire it. When in the 1970s his desire to own a DX-5 intensified, he searched vigorously for it. He assumed that several of the receivers were in private collections.
    Fortunately, his industry paid off, for eventually he obtained a Super DX-5. The significance of his find became apparent when he realized that the Super DX-5 that he had acquired might be the only one in existence!

RAYNER'S SEARCH - THE EARLY YEARS
    Les Rayner's interest in the world of radio grew incrementally in the late 1920s. He began tinkering with a few wires and dry cells, which led him to the radio sections of Popular Science; later, an Allied Radio Catalog introduced him to the marvel of shortwave listening. Before long, he convinced his mother that a boy's life without a shortwave receiver was devoid of meaning. She, in turn, agreed to advance him funds by which to purchase for $29.50 a Pilot Super Wasp kit, including tubes and plug-in coils. Since Les' mother worried that acid from a storage battery might burn holes in her carpets, she augmented his allowance so that he could buy an A and B battery eliminator too. During high school, Les advanced to an AC shortwave receiver - the ICA Conqueror. He read Radio News and Shortwave Craft avidly because they provided listings and frequencies of stations throughout the world. The magazines were bursting also with advertisements for receivers manufactured by Leutz, National, Silver- Marshall, RCA, etc. But, it was the lesser known engineering company Norden-Hauck's Super DX-5, shown in Figure 1, that particularly caught Les' eye .

Figure 1. The Norden-Hauck Super DX-5.

    Perhaps Les was mesmerized by the relatively compact, aluminum cabinet, the black, triangular Bakelite panel, or the single, knurled aluminum drum dial with illuminated celluloid scale. Maybe his interest was piqued because Norden-Hauck touted the Super DX-5, which covered from 20 to 205 meters via six plug-in coils, as the most sensitive, selective, stable, hum-free, and conveniently operated shortwave receiver on the market. Whatever the reasons, Les began dreaming of owning a Super DX-5. He did not know its retail price, but he was sure that it was out-of-reach, for his allowance was too meager ever to make its purchase possible.
    When he reached young adulthood, Les was prompted to upgrade his ICA. First, he inquired about the availability of the DX-5, and he learned that production had been suspended. He settled on a Hammarlund Comet Pro. Shortly thereafter, he finished school, settled down to married life, embarked upon a career in lithographing, sold the Comet, and abandoned shortwave listening.

THE LATER YEARS
    Forty years later, in the mid-1970s, while shopping in a Phoenix radio parts store, Les was introduced to the late Bill Pugh, then one of the more prominent radio collectors on the West Coast. Bill not only inspired Les to begin collecting vintage radios but rekindled his interest in searching for the one receiver he still dreamed of owning - the Super DX-5. For the next 14 years, at national and regional meets and conventions, Les met prominent collectors from all over the United States. No one gave him a lead on the DX-5. Eventually, one of his contacts, John Caperton of Louisville, Kentucky, invited Les to view his collection of especially rare receivers, and, to, there it sat inconspicuously on one of John's shelves. For the first time in his life, Les gazed squarely at a Norden-Hauck Super DX-5. Thereafter, whenever the two met, Les assured John that he would be a very good customer, indeed, should he ever decide to sell the DX-5. Clearly recognizing Les' strong attraction to the set, Caperton sold it to him early in 1990.
    Subsequently, Les traced the DX-5's ownership from Caperton to Dr. Ralph Muchow, Elgin, Illinois, who, in turn, had obtained it from an obscure radio technician. Years earlier, the latter had worked in a laboratory where the DX-5 was undergoing tests, along with several other receivers. After the tests, he took it home, apparently because no one else wanted it.

DX-5 CHARACTERISTIC
    After searching so assiduously for so many years for the Super DX-5, and after investigating its features once he had it in his possession, Les was struck by its incredible uncommonness and rarity. The DX-5's circuit constitutes a basic regenerative design, and five of its six tubes are run-of-the-mill, a 227 detector, a 227 first-audio, two 245s push-pull audio, and a 280 rectifier. However, the sixth tube (RF stage) employs the CeCo P1, the first pentode tube developed in the United States. A Type P-1 tube is shown in Figure 2.

Figure  2. A CeCo Type P1 tube and it's carton. The arrow points to a tube base connection for the "Space-charge" grid.

    Whereas the typical screen-grid tube provides a capacity shield around the plate while the inner grid impresses signal input on the plate, the P-1 provides a second inner, "space-charge" grid with a positive charge that accelerates the flow of electrons from the filament. The amplification factor of the P-1 is thus increased.
    Indeed, Ernest Kauer, president of CeCo Manufacturing Co., proclaimed that the P-1 was "three times as powerful as the screen-grid tube." He neglected to mention that the "space-charge" grid also introduces enormous inter-element capacity within the P-1. Unless extensively shielded, the P-1 will couple readily into surrounding circuitry and destabilize it. As K. Henny noted in Electronics, 1930, the P-1 grid-plate capacity increases in the same ratio as the gain, so using it is probably not worth the effort that shielding requires.
    Nevertheless, the Norden-Hauck Engineering Co. so enthusiastically endorsed the P-1 that it seemingly spared no expense to shield thoroughly the stages of the DX-5. Prospective buyers were assured in advertisements that, even at the highest frequencies, double, even triple, shielding guaranteed not only stable operation but also elimination of the effects of hand capacity on the controls.
    Norden-Hauck asserted proudly that workmanship on the DX-5 was without parallel. No competitor disagreed. None attempted to match the DX-5, for none believed, apparently, that the P-1 tube was worth that much effort. According to Alan Douglas, the Super DX-5 was probably the only receiver ever designed commercially to use the P-1.
    CeCo advertised the P-1 in radio magazines during the first few months of 1930. Adverse publicity followed swiftly, and the tube was pulled from production about the time it began reaching the marketplace. Meanwhile, Norden-Hauck, starting in the fall of 1930, proclaimed the virtues of the P-1 and the Super DX-5 in Radio News, Short Wave Craft, and OST
    Norden-Hauck advertisements never mentioned the price at which the DX-5 would be sold. Every advertisement exhorted readers to write the company for "details." Not many readers had the opportunity to correspond with Norden-Hauck, for, abruptly, it ceased advertising the Super DX5 in December of 1930.
    To this day, Les has no idea what Norden Hauck would have expected him to pay for a Super DX-5. Even if he could have afforded one in 1930, he might never have had the opportunity to purchase it. No evidence exists to confirm that any DX-5 ever made it beyond a test laboratory to the shelf of a distributor. Norden-Hauck appears to have realized by late 1930, just as CeCo did a few months earlier, that the extravagant claims for the P-1 could not be sustained, and, as a consequence, the hyperbole promoting the DX-5 would not endure.
    Although Les did not have the opportunity in 1930 to write Norden-Hauck for information about the Super DX-5, perhaps someone reading this article did write the company at that time, or is acquainted with someone who is familiar with the marketing strategy of Norden-Hauck. Perhaps, also, someone knows of the existence of another Super DX-5. Les would appreciate greatly any such news!

References:
"The A. C. Screen-grid Pentode." Radio-Craft,
1930, pp. 512-513.
"A Deluxe Short Wave Receiver." Short Wave
Craft. June/July 1930, pp. 45, 85.
Douglas, A. "The story of CeCo and Triad tubes."
Old Timer's Bulletin, 1980, pp. 12-13, 21.
Henny, K. "Two kinds of pentodes." Electronics,
1930, pp. 40-41.
Kauer, E. "What of the pentode? " Radio, 1930. "Norden-Hauck Super DX-5 Designed for Quiet
AC Operation." Citizens Radio Call Book Magazine and Technical Review, Il, September
1930, p. 52.

(Robert E. Grinder, K7AK, 7735 N. Ironwood Dr., Paradise Valley, AZ 85253)

Robert E. Grinder, a radio amateur since 1946, acquired his first vintage receiver, still in his possession, over 50 years ago. His current interests encompass compiling radio directories, writing historical articles about the radio industry, and restoring and operating early amateur equipment. His book "The Radio Collector's Directory and Price Guide," now in its second edition, has long been a valued reference for collectors.

Antique Radio Classified, APRIL 1997
Pages 8, 9, and 10

Click here to learn more about the CeCo P-1 AC Pentode Tube

    This is what my receiver looked like when I first acquired it. It had years of dust, dirt, and grime inside and out. The front panel had the loggings of SW stations written all over it and the top lid was covered with grime and filth.

    This is what the inside of the receiver looked like with all of the original tubes that came with it. The power transformer has rust on the top surface as did the audio transformers to a lesser degree.

    Restoration on this radio was fairly easy. Disassembly was fairly easy because everything was screwed together with the exception to some of the tube sockets which were riveted in place. All of the aluminum was cleaned with Duco's "Navel Jelly" and "Aluminum Jelly" and several applications were required to each piece in order to completely eliminate any and all oxidation and staining. The power transformer was cleaned of any grime and rust that was on it along with the two audio transformers. The bakelite trim was carefully cleaned with "Simple Green", rejuvenated with "Old English® Furniture Polish: Scratch Cover for Dark Wood", and shined with "Guardsman's Furniture Polish". The engravings were very carefully cleaned out of the original filler and new filler was applied using "Liquitex" Acrylic paint in an off white "Parchment" color to more closely replicate the aged color of the original white filler. The paint is water based so all that need to be done is to wipe some of it over the engravings and then, after letting it dry, wiping away the excess with a lightly damp rag. Great care was taken in handling the bakelite trim because it's only a millimeter thick and can easily be cracked if handled improperly. The dial was in good condition but I went ahead and did a dry cleaning of the dial with a dry cloth since using moist cloth might wind up wiping off the numbers and scale. All of the screws and hinges were cleaned with "Navel jelly" and soaked in "Simple Green". Reassembly was fairly easy and straight forward. The only real challenge was remounting the tuning assembly which proved to be tricky but not to hard. Care in covering the dial was exercised when resoldering the various wires back onto the tuning assembly. Once the receiver was completely reassembled, various resistors and capacitors were replaced. A CL-90 thermister was installed in order to protect the transformer from onrush when the receiver is first turned on. The set now works completely up to it's design.

This web page was last updated: October 2, 2016