764:. With a relatively simple rewiring, the tube heaters could be put in series-parallel to run off 32 volts, with the three twelve-volt heaters in series and a 25L6, 35L6 or 43 in parallel; the tubes would still function with the heater voltage somewhat out of specification. If run from a 32-volt supply the radio had a substantially reduced performance because the B+ voltage would only be 32 volts compared with 160–170 volts when operated from AC. With 32 volts on the plate, the radio tended to be insensitive. Sometimes only the tube heater power was derived from a windmill, and dry batteries were retained for the plate voltage supply. The advantage was that the heaters were a high and continuous load on the battery, whereas the plate voltage battery drain was smaller and intermittent. Often a wet-cell rechargeable battery was used for tube heaters, recharged by a local garage or by exchanging with a vehicle battery.
121:
voltage than the other tubes. In many designs the rectifier tube had a tap on the heater to power a dial light. The plate current was routed through that portion of the rectifier heater, in order to make up for the current diverted to the dial lamp. If the dial lamp failed, that part of the rectifier heater would have a larger current which could burn out the tube in a few months. Early radios had a resistor network to minimize the problem but this was soon eliminated as the cost of replacing the tube was not the manufacturer's problem. As with
78:
66:
50:
86:
937:
discontinued in the 1980s. Early sets tended to use selenium rectifiers in place of a tube; later sets used silicon diodes. Some of these sets were hybrid, using transistors for small signal applications and vacuum tubes in place of then-expensive power transistors. Some also included a rectifier diode in series with the tube filaments; when the set was off, the rectifier kept the filaments partially heated, a technique given a variety of names such as "Instant On".
523:
that a dropping resistor or line ballast tube was needed to drop the remaining 35–42 volts. If a ballast tube was used, the radio would be marketed as a "6-tube" radio even though one was just a voltage dropping ballast. Other manufacturers used a "line cord resistor", a special AC cord made with resistance wire which replaced a power resistor in the radio chassis. These line cords tend to get warm to the touch after the radio was in use for a while.
102:
designed so that the total rated voltage of the five tubes was 121 volts, slightly more than the electricity supply voltage of 110–117V. An extra dropper resistor was therefore not required. Transformerless designs had a metal chassis connected to one side of the power line, which was a dangerous electric shock hazard and required a thoroughly insulated cabinet. Transformerless radios could be powered by either AC or DC (consequently called
171:
hazard to users. Lacking a mains transformer, the chassis of the AA5 radio was directly connected to one side of the mains electric supply. The hazard was made worse because the on/off switch was often in the wire of the mains supply which was connected to the chassis, meaning that the chassis could
522:
Radio manufacturers departed from the traditional heater voltages of 2.5, 5 and 6.3 volts to get a five tube combination that would operate as close as possible to 110–120 VAC line voltage. For the 1935 model year, designers were able to get a 5-tube heater string to total up to 78 volts. This meant
1064:
From a 120 volt DC supply, the highest voltage available to the radio's circuits is 120 volts DC. However, with a 120 volt AC supply, the alternating current reaches a peak value of 170 volts each cycle, so the radio's rectifier and filter capacitor can supply as much as 170 volts DC in with a 120
176:
or wood case, and there were many examples of owners receiving a shock by making contact with these screws while handling a set. Ventilation holes could be large enough to allow children to poke their fingers, or metal objects, through. The same type of hazard was present in
European AC/DC sets, at
936:
Many black-and-white and color television receivers were built using All
American Five principles, including a hot chassis and series-wired heaters. The designs were found primarily in portable or inexpensive sets ranging from the 1950s to even as late as the GE Portacolor series which was finally
192:
allowed was) to limit the shock to a "safe" current level. The chassis was maintained at RF ground (for shielding) by a bypass capacitor (typically 0.05 μF to 0.2 μF) usually with a resistor connected across it (typically 220 kΩ to 470 kΩ, although values as small as 22 kΩ
120:
Many design tricks were used to reduce production costs of the five-tube radio. The heaters of all the vacuum tubes had to be rated to use the same current, so they could be operated in series from line voltage. The rectifier and audio output tube required more heater power, so dropped a larger
949:
to protect technicians from a shock hazard. Some restorers will rewire the hot chassis set to put the chassis at neutral at all times. Some designs only require polarizing the plug, while others require rewiring the power supply to remove the switch from chassis ground. Power outlets must be
101:
They were manufactured in the millions by hundreds of manufacturers from the 1930s onward, with the last examples being made in Japan. The heaters of the tubes were connected in series, all requiring the same current, but with different voltages across them. The standard line up of tubes were
172:
be "hot" when the set was either 'on' or 'off', depending on which way the plug was inserted in the power outlet. Many power plugs had two identical pins, and could be plugged in either way round. The metal chassis securing screws were sometimes accessible from the outside of the
46:, cost of the units was kept low; the same principle was later applied to television receivers. Variations in the design for lower cost, shortwave bands, better performance or special power supplies existed, although many sets used an identical set of vacuum tubes.
1126:
In older schematics, "M" was used to indicate "thousand" and not "megohm". Later on, "K" for "kilo" or "thousand", and "Meg" for "mega" or "million" became the standard, with "M" deleted to avoid confusion. Today, the symbols are kΩ and
229:
transmissions). However, these radios cost significantly more and sold in smaller quantities. The eight-tube versions cost even more, adding two or more of the features of the six-tube versions and sometimes an extra IF amplifier tube.
767:
Many 32-volt farm radios were factory-built for the purpose. They usually had two type 48 power tetrodes that could operate with B+ voltages as low as 28 volts. The type 48 pairs were parallel connected, or connected in
896:, the heater string of an AC/DC radio should be arranged in a particular order to minimize hum. Assuming that all functions are performed by separate tubes, the heaters in the string should be arranged as follows:
854:
When operating on batteries, this version had almost instant warmup because of the tubes used their filaments as cathodes. This setup was common on
Motorola portable radios commonly resembling metal "lunch boxes".
883:
There were even a few "AA4" designs, usually midget sets, only usable in strong-signal metropolitan areas, because most had no IF amplifier (although some replaced the rectifier tube with a selenium rectifier).
878:
Or, another audio amplifier tube could be added for increased audio output. To keep the total heater voltage at around 120 V, the two output tubes would have to be 25 to 35-volt types, such as the 35L6 or
716:
The 50C5, introduced in 1948, is electrically identical to the 50B5, but has a revised pinout to address concerns that high peak voltage between 4 (heater) and 5 (anode) would promote socket breakdown.
201:
Although four-, six-, and even a few rare eight-tube radios were produced, they were not common. The four-tube version with vacuum tube rectifier was of inferior performance, as they typically had no
98:
The radio was called the "All
American Five" because the design typically used five vacuum tubes, and comprised the majority of radios manufactured for home use in the USA and Canada in the tube era.
800:
or the mains supply. The battery version commonly used tubes where the filament was heated by a single 1.5-volt dry cell and plate voltage was supplied by a (nominally) 90-volt battery.
113:
The philosophy of the design was simple: it had to be as cheap to make as possible. The design was optimized to provide good performance for the price. At least one radio manufacturer,
647:
These sets were first marketed in late 1939. Canadian sets would sometimes use a 35L6 in place of the 50L6, as parts of Canada used 110 volts as a design standard. Because areas near
193:
were sometimes used or the resistor was simply omitted). Over the years, these paper capacitors often become leaky, and could allow sufficient current flow to give the user a shock.
966:
573:
The very first set of metal tubes produced included 6-volt heater tubes that could be used to make a transformer-powered 6-tube radio. RCA released their first set of these metal
155:
and first audio stage were provided by a dual diode/triode combination tube. When the detector/first audio tube contained a second diode, it could be used to provide
110:. Also, if run from a DC supply the radio had a reduced performance because the B+ voltage would only be 120 volts compared with 160–170 volts when operated from AC.
69:
Placard showing the tube placement. This set would have required an additional series resistor in the heater chain as the tube heater voltages do not sum to
728:
Another low-power variation changed the tube heaters to run on 100 milliamperes rather than 150 milliamperes. These tubes took a little longer to warm up:
776:
power supply to provide increased voltage. Vibrator power supplies could also be made to work from a 6 volt supply from a dedicated wind-charger or from a
748:
The voltage distribution has changed around the tube heaters but the total is still a little more than the 120 volt mains supply. This line-up is for an
136:
voltage of 160 to 170 volts directly from the AC power line; the rectifier, while not needed with a strictly DC supply, did not cause a problem.
851:. Note that the A battery did not need to heat the rectifier tube because, when operating from the batteries, the rectifier was not needed.
796:
to convert the 6V DC supply to AC which could feed a transformer with higher voltage output, and a version that operated from either
760:
A "farm radio" modification (usually done at the point of sale) allowed an AA5 to run off 32 volts DC, commonly generated by farm
180:
The hazard was eliminated from later sets by the use of an internal ground bus connected to the chassis by an isolation network.
1180:
526:
During the 1935–36 model years examples of 5 tube (pre-octal base or prong tubes) series strings using 300 mA heaters were:
807:
because it could be operated any of three ways: batteries, the AC line, or the DC line; typically had the following tube array:
612:
This series had the grids brought out as top caps on the signal tubes, and the 35Z4 did not have a provision for a dial light.
1007:
122:
1210:
1092:
577:
tubes for this design in 1939, using 12.6-volt 150 mA heaters instead. The original design used the following tubes:
106:)—DC supplies were still not uncommon. When operated on DC, they would only work if the plug was inserted with the correct
57:
radio set. This set deviates from the more usual AA5 in that it features an Octode mixer, though it still operates on the
788:
A number of other versions of the set appeared, including some that did have a transformer, a version that operated in a
89:
Five tube AM radio demonstrator of the single ended tube variant described below. Note "Do not ground" safety warning.
1154:
514:
The basic design of the 'All-American Five' had its origins in low-cost sets produced in the early days of radio.
42:
band, and were manufactured in the United States from the mid-1930s until the early 1960s. By eliminating a power
945:
Since the chassis of the set may be connected directly to the live side of the power line, service shops used an
749:
1096:, Third Edition, (1940), The Wireless Press, Sydney, Australia, no ISBN, no Library of Congress card, Chapter 19
1040:
863:
Since the AA5 was a minimalist design, there was plenty of room for enhanced versions, resulting in an "AA6":
1033:
The All
American Five Radio: Understanding and Restoring Transformerless Radios of the 1940s, 50s, and 60s
117:, preferred to go out of business rather than attempt to compete with 'midget' or low-cost AA5 designs.
1205:
848:
844:
226:
188:, as isolation from the mains (the exact circuit and component values were not specified although the
81:
Back view of the chassis. The compact design is aided by putting both IF transformers in a single can.
218:
181:
720:
In the postwar period, some makers built sets with a mixture of miniature, octal, and loctal types.
1200:
24:
1170:
587:
202:
156:
1175:
946:
797:
793:
773:
189:
148:
129:
103:
820:
769:
214:
209:
in place of the rectifier tube avoided this problem. The six-tube versions added either an
35:
8:
693:
581:
144:
107:
58:
206:
77:
1150:
1036:
951:
652:
984:
593:
152:
1011:
836:
210:
140:
133:
114:
65:
1052:
664:
49:
624:
574:
168:
1107:"Typical schematic of a 1948 model AC/DC radio with a 220K isolation resistor"
1194:
1136:"Mallory Radio Service Encyclopedia- 6 Ed 1948, By P.R. Mallory & Co Inc"
979:
789:
648:
971:
85:
1078:(Vol. 1) Vestal, New York: Vestal Press, Ltd. (1988); Schiffer, Michael,
868:
777:
43:
39:
31:
1106:
1080:
The
Portable Radio In American Life, Tucson: Univ. of Ariz. Press (1991)
222:
816:
605:
125:, if one tube heater failed, none of the tube heaters would operate.
620:
AC/DC designs for 110–117V usually used 150 mA heater current.
761:
173:
159:(AGC), or AGC bias could be derived from the audio detector diode.
599:
27:
655:, some Canadian sets had slightly larger filter capacitors.
872:
34:
in their design. These radio sets were designed to receive
23:(abbreviated AA5) is a colloquial name for mass-produced,
812:
692:
After the Second World War the set was redesigned to use
1181:
205:
amplifier tube, although some four-tube designs with a
167:
Many early examples of the 'All-American Five' posed a
1008:"History of the AA5 (All American 5ive) AM tube radio"
871:
as an RF or IF amplifier. This would require using a
568:
546:
Later when newer tubes came out another variant was:
961:
928:
Not all manufacturers followed this recommendation.
723:
706:Detector and first audio amplifier: 12AV6 or 12AT6
162:
658:
623:The tube array in the early days of single ended
1192:
709:Audio power output: 50C5 or the less-common 50B5
931:
556:Second Detector and First Audio Amplifier: 75
536:Second Detector and First Audio Amplifier: 77
783:
615:
509:
196:
738:Detector and first audio amplifier: 18FY6
637:Detector and first audio amplifier: 12SQ7
954:for this modification to be protective.
940:
677:Detector and first audio amplifier: 14B6
84:
76:
64:
48:
1187:(magazine), August 1933, pages 6, 7, 20
829:Detector and first audio amplifier: 1U5
1193:
887:
772:. Some factory 32-volt radios used an
553:Intermediate Frequency (IF): 78 or 6D6
147:design to save the cost of a separate
53:The Philco PT-44 is an example of the
1002:
1000:
892:According to various editions of the
696:7-pin tubes and the line up became:
569:True 5-tube transformerless version
13:
997:
741:Audio power output: 32ET5 or 34GD5
687:
16:American radio with 5 vacuum tubes
14:
1222:
1164:
1093:The Radiotron Designer's Handbook
517:
1076:Radio Manufacturers of the 1920s
964:
1176:Arcane Radio Trivia AA5 Article
1147:Wireless radio: a brief history
1139:
875:to maintain the heater voltage.
843:This version used a 7.5 V
596:and first audio amplifier: 12Q7
533:Intermediate Frequency (IF): 78
215:push-pull audio power amplifier
163:Potential hazards of the design
1130:
1120:
1099:
1084:
1068:
1058:
1046:
1025:
780:borrowed from a farm vehicle.
1:
990:
858:
835:Rectifier: 35W4, 117Z3, or a
792:off a 6-volt supply, using a
755:
184:required the adoption of the
93:
1035:, Sonoran Publishing, 2003,
909:Audio power output amplifier
7:
1211:History of radio technology
957:
932:Effect on television design
10:
1227:
867:A few sets added an extra
774:electromechanical vibrator
227:single-sideband modulation
894:RCA Receiving Tube Manual
784:Battery operated variants
616:Single ended tube variant
219:beat frequency oscillator
182:Underwriters Laboratories
30:receivers that used five
1010:. Wa2ise. Archived from
903:Ballast tube or resistor
680:Audio power output: 50A5
663:The tube line up of the
640:Audio power output: 50L6
550:Pentagrid Converter: 6A7
510:Specific implementations
832:Audio power output: 3V4
683:Rectifier: 35Y4 or 35Z3
530:Detector-Oscillator: 78
197:Variations on the theme
38:(AM) broadcasts in the
803:One version, called a
157:automatic gain control
90:
82:
74:
62:
1171:The All American Five
947:isolation transformer
941:Servicing precautions
724:"Power-Saver" version
123:Christmas tree lights
88:
80:
68:
52:
912:RF and IF amplifiers
821:Zenith Trans-Oceanic
659:The "Loctal" variant
36:amplitude modulation
1090:F. Langford Smith,
1031:Richard McWhorter,
924:Ground/B-minus line
888:Series string order
811:Converter: 1R5 (or
735:IF amplifier: 18FW6
703:IF amplifier: 12BA6
634:IF amplifier: 12SK7
559:Power Amplifier: 43
539:Power Amplifier: 43
221:tube (to listen to
177:twice the voltage.
145:pentagrid converter
130:half wave rectifier
115:Arthur Atwater Kent
918:First AF amplifier
805:Three-way portable
674:IF amplifier: 14A7
602:power output: 50L6
213:amplifier tube, a
207:selenium rectifier
91:
83:
75:
63:
1206:Radio electronics
1185:Radio Engineering
1149:, Mcfarland 1996
826:IF amplifier: 1U4
507:
506:
128:The radio used a
55:All American Five
21:All American Five
1218:
1158:
1143:
1137:
1134:
1128:
1124:
1118:
1117:
1115:
1113:
1103:
1097:
1088:
1082:
1072:
1066:
1062:
1056:
1055:frank.pocnet.net
1053:Octode converter
1050:
1044:
1029:
1023:
1022:
1020:
1019:
1004:
974:
969:
968:
967:
847:and a 90 V
744:Rectifier: 36AM3
732:Converter: 18FX6
700:Converter: 12BE6
653:25 Hz power
631:Converter: 12SA7
233:
232:
186:floating chassis
72:
1226:
1225:
1221:
1220:
1219:
1217:
1216:
1215:
1201:Types of radios
1191:
1190:
1167:
1162:
1161:
1144:
1140:
1135:
1131:
1125:
1121:
1111:
1109:
1105:
1104:
1100:
1089:
1085:
1074:Douglas, Alan,
1073:
1069:
1063:
1059:
1051:
1047:
1030:
1026:
1017:
1015:
1006:
1005:
998:
993:
970:
965:
963:
960:
943:
934:
890:
861:
815:if the set was
786:
758:
726:
712:Rectifier: 35W4
690:
688:Miniature tubes
671:Converter: 14Q7
661:
643:Rectifier: 35Z5
618:
590:amplifier: 12K7
571:
562:Rectifier: 25Z5
542:Rectifier: 25Z5
520:
512:
500:X X (push-pull)
474:X X (push-pull)
471:X X (push-pull)
449:X X (push-pull)
424:X X (push-pull)
421:X X (push-pull)
374:X X (push-pull)
199:
190:leakage current
165:
141:frequency mixer
104:AC/DC receivers
96:
70:
25:superheterodyne
17:
12:
11:
5:
1224:
1214:
1213:
1208:
1203:
1189:
1188:
1178:
1173:
1166:
1165:External links
1163:
1160:
1159:
1138:
1129:
1119:
1098:
1083:
1067:
1057:
1045:
1024:
995:
994:
992:
989:
988:
987:
985:Volksempfänger
982:
976:
975:
959:
956:
952:wired properly
942:
939:
933:
930:
926:
925:
922:
919:
916:
913:
910:
907:
904:
901:
889:
886:
881:
880:
876:
860:
857:
841:
840:
833:
830:
827:
824:
819:, such as the
785:
782:
757:
754:
746:
745:
742:
739:
736:
733:
725:
722:
714:
713:
710:
707:
704:
701:
689:
686:
685:
684:
681:
678:
675:
672:
660:
657:
645:
644:
641:
638:
635:
632:
617:
614:
610:
609:
603:
597:
591:
585:
570:
567:
564:
563:
560:
557:
554:
551:
544:
543:
540:
537:
534:
531:
519:
518:Early attempts
516:
511:
508:
505:
504:
501:
498:
495:
492:
489:
486:
483:
479:
478:
475:
472:
469:
466:
463:
460:
458:
454:
453:
450:
447:
444:
441:
438:
436:
433:
429:
428:
425:
422:
419:
416:
413:
411:
408:
404:
403:
400:
397:
394:
391:
388:
385:
383:
379:
378:
375:
372:
369:
366:
363:
361:
359:
355:
354:
351:
348:
345:
342:
339:
337:
334:
330:
329:
326:
323:
320:
317:
314:
312:
310:
306:
305:
302:
299:
296:
293:
290:
288:
286:
282:
281:
278:
275:
272:
270:
267:
265:
263:
259:
258:
255:
252:
249:
246:
243:
240:
237:
198:
195:
164:
161:
95:
92:
15:
9:
6:
4:
3:
2:
1223:
1212:
1209:
1207:
1204:
1202:
1199:
1198:
1196:
1186:
1182:
1179:
1177:
1174:
1172:
1169:
1168:
1156:
1155:0-7864-0259-8
1152:
1148:
1142:
1133:
1123:
1108:
1102:
1095:
1094:
1087:
1081:
1077:
1071:
1061:
1054:
1049:
1042:
1038:
1034:
1028:
1014:on 2017-04-24
1013:
1009:
1003:
1001:
996:
986:
983:
981:
980:Utility Radio
978:
977:
973:
962:
955:
953:
948:
938:
929:
923:
920:
917:
914:
911:
908:
905:
902:
899:
898:
897:
895:
885:
877:
874:
870:
866:
865:
864:
856:
852:
850:
846:
838:
834:
831:
828:
825:
822:
818:
814:
810:
809:
808:
806:
801:
799:
798:dry batteries
795:
791:
790:motor vehicle
781:
779:
775:
771:
765:
763:
753:
751:
743:
740:
737:
734:
731:
730:
729:
721:
718:
711:
708:
705:
702:
699:
698:
697:
695:
682:
679:
676:
673:
670:
669:
668:
666:
656:
654:
650:
649:Niagara Falls
642:
639:
636:
633:
630:
629:
628:
626:
621:
613:
607:
604:
601:
598:
595:
592:
589:
586:
583:
580:
579:
578:
576:
566:
561:
558:
555:
552:
549:
548:
547:
541:
538:
535:
532:
529:
528:
527:
524:
515:
502:
499:
496:
493:
490:
487:
484:
481:
480:
476:
473:
470:
467:
464:
461:
459:
456:
455:
451:
448:
445:
442:
439:
437:
434:
431:
430:
426:
423:
420:
417:
414:
412:
409:
406:
405:
401:
398:
395:
392:
389:
386:
384:
381:
380:
376:
373:
370:
367:
364:
362:
360:
357:
356:
352:
349:
346:
343:
340:
338:
335:
332:
331:
327:
324:
321:
318:
315:
313:
311:
308:
307:
303:
300:
297:
294:
291:
289:
287:
284:
283:
279:
276:
273:
271:
268:
266:
264:
261:
260:
256:
253:
250:
247:
244:
241:
238:
235:
234:
231:
228:
224:
220:
216:
212:
208:
204:
194:
191:
187:
183:
178:
175:
170:
160:
158:
154:
150:
146:
142:
137:
135:
132:to produce a
131:
126:
124:
118:
116:
111:
109:
105:
99:
87:
79:
67:
60:
56:
51:
47:
45:
41:
37:
33:
29:
26:
22:
1184:
1146:
1141:
1132:
1122:
1110:. Retrieved
1101:
1091:
1086:
1079:
1075:
1070:
1065:volt supply.
1060:
1048:
1032:
1027:
1016:. Retrieved
1012:the original
972:Radio portal
944:
935:
927:
893:
891:
882:
862:
853:
842:
804:
802:
787:
766:
759:
747:
727:
719:
715:
691:
662:
646:
622:
619:
611:
572:
565:
545:
525:
521:
513:
309:5 (standard)
200:
185:
179:
166:
138:
127:
119:
112:
100:
97:
54:
32:vacuum tubes
20:
18:
1145:Lewis Coe,
900:Input stage
778:car battery
667:tubes was:
627:tubes was:
304:(selenium)
251:Det/Pre-amp
217:tube, or a
143:was of the
44:transformer
40:medium wave
1195:Categories
1043:,, page v.
1041:1886606196
1018:2017-01-11
991:References
859:Variations
756:Farm radio
257:Rectifier
223:Morse code
151:tube. The
149:oscillator
94:Philosophy
61:principle.
1157:, page 39
915:Converter
906:Rectifier
849:B battery
845:A battery
839:rectifier
817:shortwave
770:push–pull
762:windmills
694:miniature
606:Rectifier
582:Converter
254:Audio Amp
245:Converter
71:115 volts
59:pentagrid
19:The term
958:See also
921:Detector
837:selenium
794:vibrator
594:Detector
174:Bakelite
153:detector
108:polarity
752:radio.
750:Admiral
236:# Tubes
1153:
1112:2 June
1039:
665:Loctal
608:: 35Z4
584:: 12A8
248:IF Amp
239:RF Amp
879:25L6.
869:12SK7
625:octal
600:Audio
575:octal
169:shock
134:plate
28:radio
1151:ISBN
1114:2023
1037:ISBN
873:35L6
651:had
139:The
1127:MΩ.
813:1L6
443:X X
242:BFO
225:or
1197::
1183:,
999:^
588:IF
503:X
477:X
452:X
427:X
402:X
377:X
353:X
328:X
280:X
211:RF
203:IF
1116:.
1021:.
823:)
497:X
494:X
491:X
488:X
485:X
482:8
468:X
465:X
462:X
457:8
446:X
440:X
435:X
432:8
418:X
415:X
410:X
407:8
399:X
396:X
393:X
390:X
387:X
382:6
371:X
368:X
365:X
358:6
350:X
347:X
344:X
341:X
336:X
333:6
325:X
322:X
319:X
316:X
301:X
298:X
295:X
292:X
285:4
277:X
274:X
269:X
262:4
73:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
