Talk:All American Five

message: Note: Atwater-Kent did not go bankrupt because they refused to make an AC/DC set. Atwater-Kent refused to unionize.Dfoley51 00:30, 7 October 2006 (UTC)
replies: text: I can buy that version, I can't imagine AK even CONSIDERING building less than a high end unit.  The old version made it sound like he was forced to pick between making a stock RCA design or going out of business.  I can imagine more than a few makers were caught by the combination of the depression, and the technological change represented by the AA5. cmacd 12:49, 22 March 2007 (UTC)
thread_title: [[Atwater Kent]]

message: "The radio used a simple half wave rectifier to produce about 160-170 volts of plate voltage." 
This would be true for a perfect rectifier fed 120VAC (120VAC*1.414= 169VDC). 
With low-cost vacuum rectifiers like 35Z5, the actual voltage was more like 125VDC. 
See 35Z5 data-sheet: http://www.mif.pg.gda.pl/homepages/frank/sheets/127/3/35Z5GT.pdf which shows 122V-127V at 60mA current
:You need to find out what data sheets are trying to tell you.  The 125 volts quoted is merely the plate voltage at which those characteristics apply.  It also quotes them at 235 volts, but I would not even try to use that as evience that the half wave rectifier produced 235 volts.
See also 50L6 data: 
http://www.mif.pg.gda.pl/homepages/frank/sheets/127/5/50L6GT.pdf 
which shows operation at 110V across the tube (add ~7V bias and ~7V drop in output transformer= 125VDC).
Yes, 50L6 is allowed higher voltages, but never got it with AC/DC construction and vacuum rectifiers; and later "5-tube" tube-sets often used a 150V-max output tube. 
The low voltage limited such designs to 1 or 2 Watts power. 
PRR
68.239.136.129 08:22, 11 February 2007 (UTC)
replies: text: All the All American Five service sheets and diagrams that I have seen all refer to the B+ voltage being around 160-170 volts.  Most of the cited links do as well.
86.132.200.242 17:36, 13 July 2007 (UTC)

text: The quoted AC voltage is the Root Mean Square (RMS) of the instantaneous voltage taken over a complete cycle.  The peak voltage is equal to the RMS voltage multiplied by the square root of two.  If a rectifier is used to power (say) a resistive load, the voltage across that load will be a little less than that RMS voltage.  But when a rectifier circuit is used to charge a capacitor, that capacitor charges to the peak voltage as current will flow whenever the supply voltage exceeds the voltage on the capacitor.  In the case of a 120 volt supply, the capacitor will charge to 169.7 volts.  In practice, the load on the power supply provides a discharge path for the accumulated charge, and the actual voltage will be somewhat less than that peak value, but often more than the RMS value. 86.159.159.194 (talk) 19:00, 14 November 2012 (UTC)
thread_title:  DC voltage 

message: I tried finding this article today and searched "all american 5" No such article, nothing relevant in the first page of search results. I tried it in Google and the first hit got me here. Can there be some sort of redirect set up?
151.204.233.138 (talk) 16:00, 18 May 2009 (UTC)
replies: text: Done. --Wtshymanski (talk) 17:24, 19 September 2009 (UTC)
thread_title:  Can't find if Five not spelled out 

message: I don't think you can really build a consumer radio that *doesn't* have AGC to some degree. Check out [] which gives a schematic of a 5-tube set that looks very similar to the schematic in one of the external links. (Can't look at the other external links because our firewall says they've got malware on them.) Notice the network on Pin 5 of the 12SQ7 with a bypass cap and connection back to the antenna coil - which is the smae conection marked "AVC" in the book above. Even the Popular Science article on "build your own 5 tube radio" says it has AGC. It doesn't cost a lot especially as the second diode is already in the tube envelope - which is what it was put there to do! (You strictly don't need a second diode, either.).  There's lots of non-linearities to exploit for gain control, it doesn't cost anything extra.  I have yet again removed the assertion that AA5s didn't have AGC. --Wtshymanski (talk)
: And check out the data sheet for the 6SQ7/12SQ7 at ] - guess what it recommends using the second diode for? --Wtshymanski (talk) 17:55, 7 October 2009 (UTC)
replies: text:  See also []. --Wtshymanski (talk) 18:11, 7 October 2009 (UTC)
replies: text:  Paul J. Nahin says essentially all consumer receivers had AVC (AGC) by 1932, see [].He also says AVC was invented by Harold Wheeler, working at Hazletine, in 1926 and it was in commercial use by 1929.  --Wtshymanski (talk) 18:22, 7 October 2009 (UTC)
replies: text: You most certainly can build a practical radio without AGC.  In fact all radios built before AGC was invented didn't feature it.  Granted, it does make the radio more stable in operation.  Most All American Fives did not feature AGC.  Almost any schematic shows the diode plate that would be used for AGC either paralleled to the detector diode plate or just connected to the cathode.  A typical schematic is shown here.  In this one the AGC diode plate is connected to the cathode rendering it ineffective.  20.133.0.13 (talk) 10:59, 9 October 2009 (UTC)
replies: text:  So tell me, what is the purpose of the 2.2 meg resistor at 3, and the 0.05 uf capacitor at 13, on the referenced schematic? As noted above, you don't need a second diode, though it does make it possible to have so-called "delayed" AVC. Why is this "fed back" all the way to the antenna coil? Sure *looks* like a filter and some kind of feedback control...could it be AVC?  And recall that there's *two* components resolved by the audio detector diode - the 0.01 uF capacitor at 11 blocks the *dc* average component proportional to carrier strength that had been detected by the diode connected to pin 4 of the 12SQ7. This dc is fed back to the earlieer stages to reduce their gain on strong signals.  Also please note the phrase "Stage gains measured with AVC made inoperative.." at the bottom left corner of this very schematic! Three references and two schematics, including the one you yourself cite, show AVC ( or AGC) was commonplace in All American Five radios. ( I really want the Nahin book now, it looks very interesting on the Google preview.) --Wtshymanski (talk) 14:08, 9 October 2009 (UTC)

text:  The 4th edition of the "Radiotron Designer's Handbook" says that sometimes one of the dual diodes had its anode grounded to prevent leak-through of the IF into the audio stage; it could be detected in the audio amplifier and produce a low level of sound even with the volume control turned all the way down. This meant that delayed AGC wasn't too practical since the only remaining source of AGC voltage was the detector diode only. This is probably too obscure to include in the article but does explain why it's common to see one diode grounded in 5-tube schematics. --Wtshymanski (talk) 21:06, 29 October 2009 (UTC)
thread_title: AGC in AA5

message: To reduce costs further sometimes a pair of 12AU6 pentodes was used, one as an autodyne converter (instead of a pentagrid converter) and the other as an audio preamplifier.
How did this reduce costs? Were the 12AU6s that much cheaper, or did they take the place of more than 2 tubes? This statement needs clarification.
:They would have had to have been less than half the price of the two tubes that they replaced (that is: the tubes; the tube holders; all the extra components required and the extra labour required to install them).  All highly unlikely and as the claim is unsourced, I have deleted it. 109.156.49.202 (talk) 15:25, 19 October 2011 (UTC)
thread_title:  Variations, 12AU6 

message: Our resident self proclaimed owner of Wikipedia Wtshymanski keeps editing the article to say that the total heater voltage is less than the supply voltage.  Since the radio has no series dropper resistor, perhaps Wtshymanski would care to tell us where the difference between the supply voltage and that which he thinks appears across the heater string dissappears to?
The total voltage of the series tubes (with the standard line ups) is rated at 121 volts (12+12+12+50+35), deliberately designed to be slightly greater than the mains supply voltage.  The series connected heaters are connected directly across the incomming mains supply (have a look at a schematic - there's one referenced from the article).  There is no series resistor to drop extra volts - a deliberate design goal.  The only complication to the series heater circuit is the dial light connected across part of the rectifier heater, plus the B+ current being routed through that small parallel circuit. 
Any discussion about a dropper resistor being required for the European market is superfluous as that particular set design was never marketed in Europe.  Although other AC/DC designs were marketed, this article is specifically about the All American five and not AC/DC sets in general. 86.159.159.194 (talk) 17:23, 12 November 2012 (UTC)
replies: text: Just a clarification on your remark: I have an RCA radio using the 12BE6, 12BA6, 12AT6, 50B5 (or possibly 12AV6, 50C5, memory fails) which was marketed in Chile, which used (uses?) 220VAC. It had a "curtain burner" power cord to drop the excess voltage. The cord dissipated as much heat as the radio! When I repaired that set, I of course replaced the cord with a modern one for use on 120VAC. It wouldn't be much good to put in an unsafe power cord, and then have to use a "travel transformer" to run the set. 2600:1702:4F55:F900:213:F7FF:FEDA:D1FF (talk) 18:59, 14 September 2023 (UTC)
thread_title:  Tube heater voltages 

message: 1.) Computer power supplies had 115/220 switches for use in Europe. Hasn't European power been 220 volt 50 Hertz for quite some time? Wouldn't a 117 volt filament string be inappropriate?
2.) Schematics listed give "T47" or type 47 bulb for dial light, it is 6.3V .15A; not listed in the article but part of the AA5 set.
3.) '4 tube set has no IF' doesn't make sense with TRF sets at the time that used IF or RF stage as an audio amplifier also. In fact using a smaller bypass capacitor on the AGC allows amplified audio to be captured and negating need for IF amp. 
4.) Mark of AA5 was capacitive coupling (not noted) but interstage audio transformers cost less than vacuum tubes. 
5.) 1N21 diodes came out in early 40's and 1N34 diode was introduced in 1946. The audio triode was a low gain stage. The IF stage, the second IF transformer was for improved selectivity, usually unecessary by FCC regional frequency allocation.
6.) Later AA5 sets used ferrite rods which were higher Q (more selective) and acted as a much better antenna (stronger signal).
7.) The "shock hazard" of the hot chasis is overblown. One would need to be touching a ground at the same time as touching the radio, not impossible but unlikely. I looked at some of the schematics and didn't see a resistor and honestly cannot fathom a need for one. There are capacitors from the chassis to the line cord presumeably to improve RF reception from a long wire antenna, I saw .05 which would give a fairly high impedance to 60 Hertz AC, definitely a timgle. The .1 microfarad 200 Volt capacitor mentioned would have bee rare and more expensive that the usually cheap parts used in the AA5.
Shjacks45 (talk) 02:48, 18 January 2014 (UTC)
thread_title:  questions 

message: There has to be a line drawn somewhere on verification of statements. Some statements are quite important; in that the credibility of the article can hinge on the validity of certain sources, and only if those sources can confer truth to those statements.  However, the above-mentioned statement is not that critical, nor is it easily verifiable from any source, therefore the use of the "unreliable source" tag is over-used and inappropriate in this case.Landroo (talk) 15:21, 13 May 2017 (UTC)
replies: text: Untagged, found another reference.  People love tagging. --Wtshymanski (talk) 17:49, 14 May 2017 (UTC)
thread_title:  "Manufactured until the early 60s" needs verification? 

message: The following Wikimedia Commons file used on this page has been nominated for deletion:
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Participate in the deletion discussion at the . —Community Tech bot (talk) 21:51, 19 February 2019 (UTC)
thread_title:  A Commons file used on this page has been nominated for deletion 

message: The reason given in the article for why the 50B5 was superseded by the 50C5 is one commonly supposed, but is incorrect. The reason given in the RCA literature is that the Underwriter's Laboratories complained that if a 50B5 were accidentally put into the 12BA6 socket, the potential existed for raw AC power to be put on the tuning capacitor stator and/or the loop antenna. (The antenna was usually mounted on the back of the case.) This information comes from the RCA document "Notes on Program Chart - Type A4548" received July 31, 1947. The term "A4548" was a temporary internal name for the new tube to supersede the 50B5 as the preferred device, which was later given the JEDEC number 50C5, actually just a re based 50B5. I contacted the UL about this a few years ago, but they had no record of the complaint at that time. I take it that the RCA document is definitive, however. The issue is that in the 50B5 pins 1 and 7 are internally connected. If the 50B5 were inserted into the 12BA6 socket by mistake, those pins would be connected. The 12BA6 is intended to have pin 7 connected to B minus ground (the AC line, often through a 68 to 150 ohm resistor, though in some circuits directly), and pin 1 connected through the first IF transformer secondary to the AVC line, which usually goes to the stator of the tuning capacitor and possibly also to an uninsulated brad in the loop antenna, normally mounted on the back. Radio manufacturers trying for UL acceptance would have to use additional insulation to get it, both around the tuning condenser and around the loop antenna. Hence, RCA rebased the 50B5 (and its companion 35B5) creating the 50C5 (and 35C5) to make manufacturer's task of getting UL acceptance easier. 2600:1702:4F55:F900:213:F7FF:FEDA:D1FF (talk) 21:49, 13 September 2023 (UTC)
thread_title:  The reason given for deprecating the 50B5 and superseding it with the 50C5 is incorrect.