Hallicrafters S120 hum at no vol and hum with volume
 

1.Working Hallicrafters S120 hum at no vol and hum with volume but radio plays decent apart from "some" hum and is very noisy with any volume on standby so something else is leaking in there on [standby] but not exactly only a 60 Hz hum but if confined there I wont sweat it .


2.All results are with BFO [OFF] and the best AC plug in polarity ,

3. History Ebay score for notalgia bedside AM /SW radio not serious SWL it's only an AA4 :D

4.Hallicrafters S120 AA4 radio has 4 new 4 Filter Caps a Diode across the Selenium rectifier ,old filter caps NOT connected ,I snipped all the old leads at the other ends .

5.Potentially affected by new rect. Diode B+ and heater voltages are in range as is the 121 VAC at power [on] after inrush current.

6.@ no volume and receiving hum is too loud IMO or I am "mis remembering" how AA5 were 40-50 yrs ago but I think this one is too loud but I have fixed much worse 4+ decades ago .noting thats about the last time I was in a vacuum tube radio circuit working at a Magnavox AD on the bench part time .ultimately into an unrelated more interesting and more $ career

I am retired decently now and plausible cash or reasonable new toy cash is no impediment as long as it's not a supercar or a spendy yacht :D

6a. Lots of extraneous noise if you raise the loudness at all in [stand by] maybe something else is also leaking in from 12AV6 AVC 1st audio in standby but I will change the mid century .001 film film cap at the Vol. pot also

7. **** Question should 50C5 control grid one volts be checked at a normal loudness on a stable Am broadcast station or volume all the way down noting max voltage tube data is 6 volts on control grid one if I read it right but I think I checked it both ways @~6v maybe half wave DC leakage ? I will replace the cap anyway its in the audio path and the wrong uf value

8a. 50C5 - AA5 reference radio and this radio diagram calls for .001 -.002 film cap at 50C5 grid one and its an .0046 Mica disk that matches others in radio from new ,maybe this thing always hummed because of that or no?


9. The signal is plenty audible over the hum at mid to elevated loudness like an old AA5 with (some hum) and not unusable & IIRC & a half wave AA4 /AA5 radio will not be pristine anyway.but IMO this one should be cleaner for a spendy AA4 noting the 1965 $69.95 MSRP is ~ $710.00 in 2017 and it won't pass a UL cert. today :D

10. Again maybe I forgot how these old dogs can be but if I can clean the hum ,that will be fine

11. It has an RF/IF align so I will leave those signal path caps in the RF/IF alone


12. ( opinions on this stuff especially the NOS tubes, cap upgrades & .0047 50C5 coupling cap for hum on recive & maybe STBY noises ), probably a new orange drop for that and where applicable

13. This AA4 radio is practice for a pre war Zenith 8-10 tube (chassis I hope ) and or a Zenith T.O. H500 ,

14. I may be open to modding the Hallicrafters a bit also if it can justifiably improve reception on AM /SW and maybe SSB but I have a simple SDR rig and webSDR for that and difficult reception.along with a chinese rubbish "Grundig" S450DLX PLL tuned field radio I picked up actually a NIB as a "refurb" for $26.00 at Amazon and an AA4 can only do so much .

I had 2 Hallicrafters S38 I cobbled into one good one in high school so I know the AA4/ AA5 gen. coverage drill here and I've had boat anchors also that could probably split one RF KC on CW and to just borderline intelligible AM or SSB all day and stable with maybe 17-18 tubes in my HQ 170 comm radio I sold to a friend .

SWL Antenna is a rudimentary 100' end fed long wire with separate antenna earth ground and soon Coax lead in and maybe a 9:1 Balun or no ?

regards

Heck of a lot to respond to there....

Quick hum diagnosis tip. If you can disconnect the B+ with a lytic still in circuit giving a couple secs B+, but keep the heaters going on AC if the hum persists when the B+ is disconnected from AC that indicates heater/line cord hum leakage (or perhaps field coil issues if it does not use a PM speaker).

If hum seems to be in the heater circuit try unplugging the set and see if it hums for the second or two it runs with the plug pulled.

Standby usually cuts off B+ while leaving heaters on. If audio/hum persists in standby then there is something wrong with the standby mode.

There could be a H-K short in one of the tubes.
The circuitry is the same as the earlier Hallicrafters models, except for the rectifier circuit and heater drop. The year earlier models used a 35W4. Why they did it that way is anyones guess! It couldn't have been a cost savings.
The Hallicrafters sets of this type were very insensitive on the high band.
IIRC, in that model, the standby switch will only cut the B+ to the plates and screens of the converter and IF tubes.

++ on H-K short. recently had a Zenith AM-FM with a shorted
12BA6 IIRC. Hum & distorted audio.
Warm up & pull each tube one at a time EXCEPT audio out & see
if one makes it go away. After that its checking any new work
for proper values etc. EVERYBODY makes mistakes !!
BTW the rectifier should have a dropping resistor after it & the
selenium unhooked at one end.

73 Zeno:smoke:
LFOD !

Thanks for the plausible reply here :thmbsp:

Aside from my old man rambling and way to wordy OP ..Nothing complex at all here but no answers or opinions to my specific questions but in all fairness maybe better answers now but it's only an AA4 aka AA5 radio without a diode tube > 1961 to 1965 Hallicrafters S120 and any USA mid century vintage radio enthusiast or old dog enthusiast like me should know what it is and the preceding S38 full AA5 radio and the late 1930's Zeniths and some others and the boat anchors ofc OTOH millennials maybe and probably not just because of timing :tongue:


We should all know those and the rest were PM speakers for ~ decades prior to 1965 like maybe a Catalin madness or Plastik AA5 radio or '40's Zenith T.O. anyway apart from a 1952 Seeburg 100 B happy days juke box I owned , salvaged and repaired in H.S with good tunes and usually up to date selection labels.



Beyond multiband tuning coils , a BFO and such ,a phono plug or a treble cut a 1935 AC/DC - AA5 AA5 is an 1965 AC/DC - AA5 /AA4 but with a PM speaker and mid century 7 pin small tubes on the latter.


If you unplug the radio playing normally the hum vanishes instantly while it still plays .thus the heater/line cord hum leakage you brought sounds plausible but I'm thinking more heater leakage but both may be a good place to look ,thank you again



Apart from the standby noise at any volume, above zero ( fault there too or unlikely related fault ) ................................,

I'm thinking common mode AC hum may be DC ripple or heater/cathode ,hum is present at both REC and STBY maybe a faulty no name new lytic of three or all of them the Pay Bay seller put in and or AC potential leak in the B+ or any DC or audio grid or something in there


OTOH NOW that I remembered the hum clears at unplug [ON],maybe a cathode or (heater leak like you brought) in a tube or HK short in a tube diesel jeep mentioned here . :thmbsp:

Even with the unplug [on] result may be pointing away from the Lytics if I am thinking well I will put my DVM on ACV at B+ and DC and see what I can but I don't know the AA5 tolerance for that like 1.0- 1.5 volts on an automotive alternator .



Variable amplitude and cadence with volume Standby noise is in addition to common mode AC hum at STBY and REC. but not an issue if REC is unaffected here ,its never going to be valuable radio on the 21st century AFAIK anyway and a lot of pay bay sellers are asking high on these. IMO,they may think it's really a decent SWL radio :D

STBY noise is like an uncontrolled variable @ loudness control. oscillation (s) and maybe harmonics @ not a stable one as you vary the loudness pot and at the schematic STBY switch doesn't seem to open the Plate B+ @ any tubes but more something at AVC 1st audio tube (or to it ) to the volume pot or .001 film cap there but maybe from the AVC /first audio tube or IF but not a control grid or plate

I need to revisit the official schematic .pdf here about that. but AFAIK looking at the dia. STBY SW . is definitely NOT tube plate voltage interrupt in the schematic keeping in mind this goes back 4+ decades for me and I was never into AA5 beyond a typical and nearly deaf Hallicrafters . S38 AA5 and more deaf National radio S54 and just Lytic caps ,dial lamps and tubes and on those & new strings on the S38's . the S120 will be getting a bandspread tuning string also .

The common mode hum is maybe leaking in after the standby SW or just included somehow ,

Beyond that I read the .001 film cap at the Vol. pot can make these deaf or hum and commonly does .


Maybe importantly the 50C5 beam power control grid cap is supposed to be .001 uf Film cap in the S120 schematic and .001 uf -.002 uf at AA5 reference diagrams ,it is a .0047 Mica cap and definitely OE so whatever that cap is doing or not has been since day one and no opinion on that or NOS tubes just because of the age of the tubes and no emission tester here maybe I should wait or just put may caps on order in it and see if I want to change out the Lytics and (now) moreover the tubes before lytics depending on the results or my ouija board :-\


Again I am getting 6 Volts at the 50C5 beam power AF control grid instead of zero or (neg volts) specified Imagine all that and maybe a hum since new and an uniformed buyer perhaps or is that a stretch electronically ?


Another question I posted is the zero to negative volts 50C5 beam power control grid voltage spec. valid at normal radio play volume power on or @volume [OFF] power [ON] or no? IOW do I need to close the volume pot for a valid result

+++ thats sounding plausible along with the tube heater leak .

the audio distorts at lower volumes but I think thats hum garble and not so much thd+n although that present thd + n may get some improvement that won't hurt at all with the tubes in any case and if the crummy and small midcentury alnico speaker can produce cleaner audio that is .



OTOH there is a high thd+n result going on I don't recall on some other AA5 but I did not associate that with the hum given the crummy even for a comm radio speaker in there in a less than ideal metal box and you all may be onto something here.:thmbsp:


The radio is getting all new NOS maybe same brand tubes either way ,they are also less or same as the new ,tube store tubes but they arent spendy audio tubes or RCA black plates that IMO aren't any different sounding from a GE grey plate and I had a lot of them off the jobber store shelves back in the day and we didn't worship a GE 6L6 vs black plate RCA we never thought was anthing special or the various name brand 5886 & other tubes vs another name brand


OTOH we didn't mind a same tube output section or matched tubes and output tube bias accordingly or in any case appropriate on the PP and PP /PP amps ,

AFAK the MTBF on all that was not a wide variance @ a name brand consumer grade tube /consumer OEM unless a company has a known dog tube or line of tubes like some of the CRT and specifically IIRC moto (Motorola ) 24" color CRT .

RCA , GE & the others made re labeled and print screened tubes for any number of reasons and the JAN tunes ( Joint Army Navy) and TV /Radio brand tubes and tubes outside of tube # product coverage for each other too .


OTOH the exotic metal cable audio fools outside of legitimate matched tube rolling and BIAS accordingly on the outputs think they can hear the black pate RCA & exotic cable swindler speaker wires and other hi zoot cables ,garden hose AC cords in a 15A Romex circuit on a public utility ,HUge power conditioners on a well designed and large spendy monoblock amp and spendy data cables too :D

That said tonite I will order and install the NOS tubes upon arrival before anthing else ordered already given all that facts and wisdom here and the in spec. voltages outside of the 50C5 control grid and wrong uf cap there at the control grid .

1. Try substituting the tubes with new ones, to rule out heater to cathode leakage.

2. Verify that the new capacitors are grounded to the same point as the original can, this can be critical.

3. Verify the "across the line capacitor" is good and connected properly

4. Check if the volume control is bad, jumper the middle and negative terminals of the volume control to see if hum goes away.

Thanks I will unhook the selenium rect. and maybe put in the obligatory resister I noticed was not there but...............,

Again I will order a tube set tonite and it goes in before the other except maybe the CORRECT uf 50C5 cnrtl .grid film cap & maybe the notorious .001 volume pot film cap in those Hali. S120 .

FWIW I checked the values of installed replacement parts already and the related wiring and anything that may stand out as odd in general like that and I cut the B+ leads on the OLD Filter Caps the seller left in with the new Lytics in parallel .


Edit
FWIW I'm not accustomed anymore to a prolonged warm up I haven't timed but it's longish on this Hallicrafters, I think even for 5 or 17 tube like my HQ 170a I had so maybe there is a dog tube in there or it's a typical AA4 /AA5 warm up I don't recall but its only a 30 sec warm to play anyway

Again I found and will correct a wrong .0046 uf mica cap at the 50C5 beam power tube control grid noted above and its definitely a factory boo boo and pretty much any AA5 final tube control grid will have the correct .001-.002 film cap there anyway given that a 1935 AA5 is basically a 1965 AA5 ouside of maybe a PM speaker on later AA5 's but I never saw an electro magnet speaker AA5 or pre war AA5 IIRC .

I only tinkered with and owned the larger 1937-1939-1948 table top (tombstones ) and console Zenith all wave's or late 40's console AM/low band FM. and later mid century stuff ,console pulls and better and my happy days jukebox /45rpm record grinder :smoke:

Thanks and all good points :yes:

1. All new NOS tubes will be ordered before I log off windows 10 and rolled in one at a time to eliminate an offending tube if any out of the lot of (4) and all rolled in anyway like I intended before I bought the radio .



2. Cap grounds are grounded to same as OE and double checked ,


3. AC line cap seems to be OK but I don't have a CAP tester and maybe should replace it anyway and probably will . I thought about that and may have it on my Cap order and if not I will get one .

4. Volume plays and works fine outside of a too loud to allow at low volume AC hum but there's a specific and notorious suspect .001 film cap there I will replace and Yes I can jumper the pot anyway . maybe the pot is leaking an ac potential or DC ripple in to the audio path , good point but the hum amplitude is constant and actually garbles speech at lowest volumes .

I have seen 2-3 AA5 sets with field coil electrodynamic speakers, not common, but some did it.

What matters with the output grid is that it be negative with respect to the cathode. One thing you can do is connect a large cap (.22-10uF) between the output grid and signal ground to bypass any hum from proceeding stages to ground, then put the meter common lead on the grid and the hot lead on the cathode...That should give you a positive voltage indicating the cathode is positive WRT the grid and that the grid is negative WRT cathode.

lacking a new tube set delivered yet the common mode fixed hum daig.process is going slow at least at my chosen path given I am chasing a possible tube heater /cathode fault .

Using my secondary phones for a signal tracer at C15 to VOL pot distorted audio and same fixed hum,16 away from Vol pot same result

@above testing update the tell is the hum bogey is ahead of the beam power final tube ,or into the 50C5 tube or one tube back as I interpret the results and ofc the 50C5 control grid cap and signal needs to be fixed and at least have the correct uf capacitor if nothing else ,

Note today thd+n is virtually and suddenly making the radio nearly useless , no change @common mode fixed hum!
Maybe a deteriorating tube or discrete circuity part is my guess without an ouija board or a wise leprechaun LOL

Update 08.11.2017 17:27 PDT .


Hum diag . For bad tube leaky heater or H C short @ a tube I can pull tubes one by one power [up ] (only after the other heaters cool so you dont over volt a heather and fry a tube electronics 101 heat vs restive load EZ peay s B4 Univerity study too ! ) ag if i use alligator clip to puled tube hater pins I first though of decades ago in one of these but it was the Lytics !


I have a testing update and the tell is the hum bogey is ahead of the beam power final tube ,or into the 50C5 tube or one tube back (or more ) as I interpret the results and ofc the 50C5 control grid cap and signal needs to be fixed and at least have the correct uF capacitor if nothing else ,

Note today thd+n is virtually and suddenly making the radio nearly useless , no change @common mode fixed hum!
Maybe a deteriorating tube or discrete circuity part is my guess without an ouija board or a wise leprechaun LOL

lacking a new tube set delivered HERE the common mode fixed hum daig.process is going slow at least at my chosen #lazyfair slow path given I am chasing a possible tube heater /cathode fault .but the new tubs > sWill fix that anyway if that is prob

Using my secondary phones for a signal tracer at C15 to VOL pot distorted audio and same fixed hum,C16 away from Vol pot same result




.O

4. lacking anthing better like a signal tracer I got creative or started tweaking without chemicals who knows ? I used my Sennsheiser HD 280 secondary headphones for an audio signal tracer for audio and hum .

Result : same as above Distorted audio same fixed hum @ Vol Pot C15 ,C16

ofc . This AC-DC AA4 Hallishafters S120 is just a a nostalgia bedside radio for me ,a mid century adolescent bedroom trophy or brand starter radio and a nearly deaf SWL radio anyway .that would be outlawed today .

I bought it for what it is ,not what it is not ,or never will be :!:

I came up on that generation and been in more than few tube radios ~but not much tube action since 1970! :(

When you say last and first tubes in the string that is rather vague...Better to refer to them by their functions: converter(AKA 1st detector), IF, Second detector/AVC/1st audio, audio output (at least that is what the line up would usually consist of in an average selenium powered AA4).

Do you have any clip leads (that have small alligator clips on both ends)? You can pull a tube (google it's data sheet to find the heater pins) and use 2 clip leads to reconnect only the heater leads to the circuit....It is simpler than using a light bulb. Avoid using the light bulb as a substitute heater the bulb has to have the same voltage drop and current rating as the factory heaters or it will not work (and it could burn out the other tube heaters).

Got a diode and a small cap .001uF or less? You can make an AM signal tracer easily just use the diode as a detector and the small cap to filter RF out of your listening device. You can even add an amp* between the detector and the listening device.

*Make sure the amp is battery powered or that there is a power line isolation transformer powering the radio.....If you neglect that then you could create false hum from connecting devices with different signal ground references, and or damage the devices.

EDIT 08.15.2017
Yes and more and lots of solid state ( SS experience ) note my education futher down


Noting you must let ALL the tube heats cool B4 next power up lest you fry a tube or are stupid and lucky but the rest of it is 4 + decades OLD NEWS but the AA5 radio back then had bad LYITCS as I suspected the reason > AC hum much Much LOUDER than this RaDiO !

This hum is forward of of the DUAL TRIODE FIRST AUDIO /AVC 12AT7 PARALLEL WIRED DIODE PLATES or maybe 1st audio cntrl.grid if you happen to know what all that is


FWIW I was reading tube DATA and building projects (transformer powred ofc) out of RCA tube manual ref. designs we all used 4 decades before you were conceived & later getting proper EDUCATION

I dont mean a vocational certificate diploma mill or High school but >>>>>> Electronics and Solid State Engineering study but not tube radios there LOL .......maybe NIXI tubes on some counters or just to make something red hot explode or melt for a prank or some lessons but not many


TBH I was humoring you
.
4 NOS tubes and circt. parts arriving soon may fix all this while your sig trce Detector diode idea is very good and detailed
I am too to lazy ti gin up a proper circuit trace jimmy rig in an Altoids Tin ,with a diode DETECTOR probe capacitor uF like you say that can discern an AC hum ,an OP amp, a battery and buffer caps & whatever for a Ti PDIP- 8 op amp .


I have it covered note my edu. and now that I spent some-refresh- tine with the schematics ...I can read these old crude AA4-AA6 circt. diag.and figure them out ...........SRSLY they basically haven't changed outside of the the tube sockets since 1936 BTW
h

and thank you for your rely

full stop







,

If by millennials your referring to me....Don't, I'm not like 99.9% of those around my age.

Also don't assume I'm not knowledgeable on tube radios. I've owned well over 200, worked on ~80% with a 95% success rate, and have over 130 presently...Not to mention all the tube TV work I've done.

I say vague on your pulling the first/last two in the string vs using the function names since you could be referring to the signal chain (which is a standard topology), or the heater string which does not need to be wired with the tubes in any fixed order.

Um.. by convention, in a series heater string, the first audio tube is usually at the bottom (ground) end of the string to minimize hum pickup. The OP might want to verify that the 1st audio tube's heater is indeed at the bottom of the string, in regards to his hum problem.

(Edit) Also, the rectifier (e.g., 35W4 etc.) is conventionally at the top of the heater string to minimize heater-to-cathode voltage. The audio output (e.g., 50C5 etc.) is usually the next one down the string.

EDIT :
without an electronics or EE education (~ 3yrs EE study at a universality like CAL State Electronics and Solid State Engineering study (like me) or bench tech experience (like me >part time + short timer ) and concomitant qualifications all that sounds like unqualified and hobby opinions to me and you are wrong about the heater wires ( I was informed below ) on these radios anyway stick to your day job mate






I

Dude, just to reiterate, check the heater wiring to verify that the 1st audio tube's heater is at the bottom (ground) end of the string. If it's not, it could be introducing hum downstream of the vol. control

^^^ Interesting and makes sense electrically unless the fundamentals have changed since I was in school :D

IIRC even some transformer heater wiring and lead dress was very specific in something like a boat anchor comm radio or spendy audio gear and a there were a only a few AA5 variants and virtually AA6 radios , the pre 1936 AA5 variants and the different tube envelopes & sockets for the same bloody AA5 circuits and the superior Zenith T.O. variants :D

Your edit that makes perfect sense . I tried to stay away from AA5 and AC/DC rubbish in the hobby but my 2 exceptions today are this deaf SWL specific model Hallicraftors S120 nostalgia radio for me and maybe a Zenith
Transoceanic H500 legitimate AA6 variant .


Benching TV & radios at a Magnavox AD when I was doing that there at 1967-1970 , Most of us understood a given signal path or output path tube order to function because you had to know it to fix the bloody things and where to start anyway .

we didnt have all these web forums and web sites or FUD :D

But your info here is not FUD .☺

EDIT 08.15.2017 20:30 PDT

I just assumed anyone replying to me would know the mid century AA4-AA5 tube order to function order correlation that hasn't changed much since 1936 and we had had to know all that in our sleep in school and how to to build an AA5 in the lab too .and that was H.S. advanced electronics lab before college which wasn't tubes anyway 3 periods a day BTY

I think I saw some electromagnet speaker AA5 photos . I amassed a huge old radio web image collection with actually thousands of images but I'm not so sure there were many or any of those electromagnet speaker AA5 past the 1936 reference AA5 revision but if they were I may have the image trus`me


That other thing may be something if its off spec. with a (correct uf capacitor to output tube cntrl. grid we don't have now ) . so maybe that should be shelved for now. especially if we look at the cap uf in there at output tube contrl. grid as opposed to spec that may be bigly over volting output tube cntrl. grid now like I think it is and I see +6V on my DVM .


I can verify so far the 50C5 output tube control grid input is indeed +6V and the output tube 50C5 GE tube data spec is specifically 0 to neg volts with no mention at all about the cathode only at a brief glance of pin out volts .

AVC /First Audio and Output tube and first IF amp tube heater and plate volts are fine.


I did not read the diode plate voltages at the 12AV6 First Audio AVC Duplex Diode Triode that are wired to each other in the radio and the VOL pot is not deaf anyway so probably nothing to see there given the vol pot is ranging normally and phone volume is normal but lots of distortion that may be something else ,a tube or one of the caps I ordered .

I am sure if I had the parts and tubes like you surely have in your workshop this radio would be done ,

So that where it ends for me until I get my NOS tubes and or the caps on order, beyond that ,maybe tomorrow now the clever one at a time tube pull with alligator clip tube pin heater leads you mentioned I have the leads here at the ready

Edit:

oh you have any photos here or at the usual spots of your hoarders conflagration of electronics refuse or is it a nice tidy 200 radio collection?

that sounds plausible and also given that the factory put in the incorrect uf value output tube control grid cap,

SRSLY no joke and it exact matches mica caps all over that radio and its a .0046 uf Mica vs an .001 presumably film cap it's supposed to have there per the schematic and the AA5 reference design that can go to .002 uf also
who knows what else they did .

I'm obviously not an AA5 or even radio expert like most of you here , so the input is all good and teaching me thank's :banana:

During my career ,some of those screw ups and product were butt of inside humor or more or a PITA ,

IOW some misplaced wires would not suprise me in a USA mid century home radio ,they already put the wrong output tube cntrl.grid cap in that crude radio with 1936 AA5 budget model ciruits in a deaf SWL 1965 radio .


It's almost criminal and that radio or a AA4/AA5 would be today because it can electrocute us without much provocation ! You cant make that up :tongue:

I never worried about being electrocuted on a hot chassis receiver, as I've been doing it for over 60 years!
I also worked as an Industrial Electrician for 30 years, so I'm no stranger to even higher voltages.
I have one of those receivers in my warehouse, somewhere. I remember working on it and it had a floating B- line. Trying to remember if it's U/L listed.
On mine, someone replaced the 'lytic with a metal can type and installing it tied the B- to the chassis, which made it a shock hazard. I corrected that right away.
Those type of SWL receivers generally didn't sound that great, mainly they were made for speech or code reproduction and not really for music.
Also, that receiver was one of the last ones built in USA. They seemed to shift their production to Japan. Possibly, they used what left over!

QUOTE=dieseljeep;3188044]
I have one of those receivers in my warehouse, somewhere. I remember working on it and it had a floating B- line. Trying to remember if it's U/L listed.
On mine, someone replaced the 'lytic with a metal can type and installing it tied the B- to the chassis, which made it a shock hazard. I corrected that right away.[/QUOTE]


Right AFAIK AA5 wasn't a metal Lytic ,that I recall and sometimes wax paper covered lytics laid in with the circuits instead of on top like this radio that sounds thats reckless or stupid on that radio you fixed good eye !


Setting aside the selenium rectifier and Zenith T.O. with an RF amp , the last AA5 tube radio was basically a clone of a 1936 reference AA5 even the Japanese radios and that time they were not uncommonly rubbish products anyway IRRC one could get get a chep no name or maybe regency Japanese or Taiwan AA5 for less than $10.00 in the mid '60s with the currency exchange rates back then.

IRRC Sony never made AA5 tube radios but I may be wrong and they got into the first Sony pocket transistor radios instead of rice cookers late like 1955 I think .

I read the Japanese S120 Hallicrafters AA4 had Japanese parts or a lot of them ,thats one way they said to tell if they had a Japanese made S120 AA4 or whatver


I had a number of boat anchors and comm, radios , 2 Hallicrafters S38 AA5 and a National Radio S54 AA5 and a Hammerlund HQ 170A (w/a squaker ) like all that and the marine radios on my offshore power boat money pitts I had so I know about comm. radio speakers and that audio.

OTOH This radio has elevated thd +n way more than it should or my other AA5 radios and the other radios above and the fixed hum that is too loud and garbles speech at the lower volumes .

Again SRSLY 50C5 beam power output tube has the Wrong value control grid cap and that cntrl. grid is over volting +6v + more if factor in the negative volt spec. but its a work in progress . I will know more with the new tubes and parts it could be tube and or circuit faults or something ahead of the 12AT7 AVC First audio contl. grid see below

The radio gives me the same distortion and same hum at the VoL. pot and center tap .head of the 50C5 output tube


Lets allow an argument that I didn't buy this deaf SWL AA4 for music . Bd'cast AM Frequency response is typically 40 Hz–7 kHz with a 50 dB S/N ratio at best and this radio can't make either end .

I been an Audio enthusiast since the mid 1960s & studied the popular digital audio codecs in depth more recently but not like what snob audio fools think hires is ,they knew what we could hear in 1950 and 16 bits is plenty if its done well :tongue:,

LOL those snob audio fools think they can hear different color tube plates in an amp with ~1% thd+n and a difference of adequate CT11000 copper wires & cables and AC cords vs the exotic metal cable fool stuff too and hires over good 16 bit in the same production but the industry is banking on those fools daily !

Lets allow an argument I may not the guy to be talking to about loudspeakers :tongue:


Lets allow an agrumant that if you have a post 1936 AA5 it wasn't basically any different at all than a 1936 AA5 unless it had an RF amp in the first tube on the radio side of the antenna like the Zenith T.O or a tone circuit pr phono in. or it was an AA6 variant but the same anyway as far as AC and B+ ,you can only do so much without a transformer in these .

I don't know if you attended electronics school but belive it or not we did learn some things an enthusiast may or may not know in some corners but we weren't on a TV radio curriculum for the most of it at all especially being near Silicon Valley if you know what I mean and we were all recruited back then ,

I changed study and career paths that ultimately paid and kept me more engaged and some would say well traveled
I ended up with a generous fortune 100 company corporate retirement plus , at 55 :tongue:


.Well then ,then you must be very lucky or know what not to touch & how not to put yourself in harms way here with these lethal contraptions 99.99 % of consumers simply won't know today given that my radio is 52 yrs old and that would apply to a higher number of folks today without the tribal knowledge about all this so perhaps spreading FUD on web about all this or just minimizing this hazard anecdotally is reckless or no?

.
Lets allow an argument that aside from perhaps being reckless downplaying the lethal potential of these radios there may be folks without yours or an understanding of electrical current paths reading all this or have no idea what these 52 yr old plus radios can do to them without much provocation :

no need to debate all that ,the science around this is settled science )

lets imagine I'm in my 50's riding a competition level X country mountain . bike @ least 75 mi a week in the season and getting some gravity and getting laid regular with my real nice ,smart good looking professional gal Tuesday and maybe Thursday too and current weekend getaway squeeze and feel a little tired around all that thinking my GP may reccomend a vitamin regimen and maybe something else eh?
EDIT :

Well it was a cardiologist and sudden coronary by pass surgery without more than a days delay ,
wholly unexpected by me or my GP or anyone that knew me at all including the gym trainers .

The analogy here is these radios are lethal and you are being dismissive about that and your GFI outlets are not foolproof and neither was my significant exercise regimen .if you can not see the analogy here perhaps have someone explain it to you .


.True story here and ......We never know when the bogey man is coming .:tongue:

Good God, all that dialogue over a S120!!!
BTW, I'm a little more than just a hobbyist, plus I have four years of Tech school, associated with my Electrician Apprenticship. Plus, several years of practical experience, that no tech school can offer! Why do you think, I knew exactly what set you were working on, if I didn't have experience with the faults of the set.
Another thing, I've been equipping my workshop with GFCI receptacles, ever since they became available, something like 30 years. It minimizes a shock hazard when working on equipment like this! :thmbsp:

+1 Had the same thought.

Sounds like he went here for his medical work. https://youtu.be/jWMO3rAD98k?t=1m32s :D

???

Too bad you have stooped to this level and don't value a good argument but given you may wholly overestimate your abilities here I am not surprised :tongue:

Consider all this :

1. You may believe you are an above average Millennial .

2. Where are your valid statistical data and test subject data stores or [citations] and or some PhD peer reviews and papers to support your statement .

3 Did you use trained or random test sample groupings for your conclusions,controlled conditions, any accredited test proctors or any clinician or standardized testing ,

4. Did you use a statically valid number of qualified or peer test subjects?

5. Did you use reliable double blind ABX testing like we do in pharma research ,statistical validation,engineering validation ,field product reliability
validation, random MTBF destructive & competitive testing and many disciplines or no ?

6. How did you arrive at your statistically valid conclusion or anecdotal subjective or cognitive bias hypotheses ?

7 . Let's allow an argument of how many of your radios statistically just needed a random tube substation ,some cleaning , new connections ,De Oxit or only obviously visibly bad discrete circuit parts ,just new circuit part hook up wires jusk electronic cables ,a RF or IF coil or related cap again visibly bad parts or tubes ,only a line cord , a pot or switch (s) ,recap instead maybe resistors .lyrics or a loudspeaker.or a comprehensive electronic restore .


7.a Le'ts allow an argument that most ME, EE, ,EE grad EE undergrad deals in statistics ,materials science ,electrical conductivity, circuits ,thermal design, micro circuits ,controls,software and HDWE , diffused silicon , metallic alloys ,refined base metals, elements rr diffused exotic metals......... ,

or fabricated materials ,network controls ,fail safe and and devices and the scientific method , what I missed here you probably can not imagine outside of a lab ,university or private sector tech ,industry ,materials , eng. ,science and silicon .

8 Let's allow an argument that Discrete circuit superhet. AM radios were not rocket sconce since 1939 or perhaps well before that and niether are yours or mine .

7. How is working on 200 or even 2000 collector or refuse radios a credible electronics qualification as with a professional vetran techician resume and concomitant qualifications . or an accredited academic and lab A.A. , EE grad or EE undergrad studies ?

7a. Let's allow an argument this would be absurd if you know better more on that later,

9 . There are those that say some Millinials a have recieved poor educations and were never thought to think critcally or value a good argument like scientific or geo political debates and supporting arguments like technical, engineering ,medical and science necesities .


9a. I raised a now grown Millinial ,extended millennial family & virtually most the friends when I wasn,t abroad or far (work) and lots of them are *or were* lacking desirable educational and employment or skills ,attributes or situational skills we found that in the 105 yr old Fortune 100 global company I retired from managing at also and some of them typically over estimated thier abilities with exceptions ofc.***

9b. ***** This is not unto itself an indictment of Millennials at all there are many ,exceptions but more an indictment of our failing institutions .****


10. Let's allow an argument that without concomitant education ,experience in the private sector or related pubic sector and qualificatins any given enthusiast may be confused about all this and over estimating thier abilities ?????

11. Let's allow an argument you appear to be wong about an AA5/AA6 heater order and Old coot 88 is the smartest one in the room abuot tube radios or more


12. I was there (ONLY part time short timer +_hobby ). I chose a different career and study than TV radio & ultimately no electronics beyond the current hobby and , ahem ....hacking PC 's maybe decades ago just to look but never private citizen except a prank to someone I knew with a restart out for them (from mail attachment , all the geeks did it then ,


Today hobby are Nix & Windows 10 PC PC, solid state ,digital CE repair only if I have to and I can ,digital codecs ,Window 10 software validation and I/O throughput Linear Power supply class A+B amplified devices like amplifiers and 5.1/7.1 AVR and PWM/PSU & complete LCD TV repairing , LCD TV panel LED today but not for$$ I dont need and not public and not frequent like a bench tech )


13. You have to respect the EE's that make all this possible and moreover the real techs today and the old school techs that get it done and blazed the trails and figured out and fixed the many EE's or production boo boos and still do today in the field its not like a hobby at all . My radio her came new with the wrong 50C5 cnrtl grid cap

14. except for the good heater wire order and related heater cathode faults noting it getting all new NOS tubes anyway I have now

I have what we call a null and what I aleady new here all along but din't call the folks on it and dismissive FUD about about the AA 4-5-6 lethal radio hot chassis that can fry someone without much provocation

Nonsense about electromagnet speaker outside of the scope of this thread or 80 years now or about my radio and ( an unqualified opinion ) about my radios thd+n distortion and speaker that is poor one but not to this high thd+n I hear

An opinion without any supporting arguments or direct observations or inquiries about the severity of the audible distortion ,comparable or ,at least the volume setting.

A qualified conclusion or peer reviewed opinion result is called the scientific method where I was educated some folks may not be familiar with , and you missed something about heater wires you were corrected on

15. trus`me I can fix this radio on my own and your LCD TV or PC and more presumably without vacuum tubes ( I can fix some if that and figure out the rest by reading the circuits (reference design) ) and tube data and whatever testing I know how to do

.You ever seen a discrete AM radio with a complex Compactron tube ?

You now what scan line NTSC color TV demodulater (s) do or what they are ? >I worked on TV's with those in a TV shop and way more complex stuff ,some at CAL State ,more abut that later


16. IOW maybe ,Let's allow an argument to your day job instead of advise on these radios or get detail observant here ,presumably you are not an EE engineer or undergrad and who knows what kind of radio tech?

EDIT : 08.15.2017 08.15.2017

17. I never mentioned where or exactly what I studied anyway ,since the subject is tube radio, . most folks don't understand it anyway ,you have to be there or in the business .



17.b LOL.. After High School Grade 10,11,12 Advanced Electronics & Lab
3 hours per day 5 days a week and some vac.,tube study + projects and same for Solid State and ,some computers and and lab inst.+ math drugery for all this ...................,

Our HS instructor for 3 yrs was an E,E, and industry & spared no money funding all this in a new dedicated electronics lab building with frosty cool AC too and the best labs this side of a spendy university .

1967-1790 H.S, those were optimistic and superb upper middle class times for us with obligatory nice vacations amd some weekenders & summer (but coll.. prep drudgery lots' and I worked hard too also ) and America had the Apollo missions

Then there was all this :

18. LOL before my unrelated career subject degree at Cal State my most significant related edu. was Electronics and Solid State Engineering study (~ 3 yrs) at CAL State that was not so much about tube radios and TV or a usually poor for profit tech school diploma mill study to a dead end job like a (** by now**) a vanishing TV shop bench job or fixing office copiers or printers in the field or pulling cables for TV content productions amd pooling CATCV cable and putting yip TV dishes or selling or Geek Squad at Best buy


: 6 Years here TRUMPS a thousand radios tongue:

full stop .



.

:D They say "talk is cheap" ....

And ,

Thank God here at VK we don't pay by the word , cause this dude would have a $10K bill after a week of posting :p:

:thmbsp: PS , NO I most certainly did NOT read the entirety of the post before mine .
Like the old proverb , oftentimes the more words there are , the less is actually being said .......

hint :

yes it was wordy see the edit ,:D

# That'a a good point I may delete the anecdotal drama rubbish or append it
FWIW that drama was the analogy to a lethal radio and common design here a poster was dismissive about and his GFI outlets or mine are not foolproof, they are not crowbar switches or fast blow fuses or isolation transformers a fool-would not own if they work on a lot of these AC DC tube radios . :yes:

They say you cant fix stupid and electricity doesn't care :D

ppfftttt yes too wordy , see the edit and it should be clear now !

OTOH maybe the original direct reply to another was an analogy with a specific intent over your simple mind anyway :D

yes it was wordy see the edit ,:D

pffttt read the edit or have some one explain it to you:thmbsp:

:nono: When you resort to hurling personal insults at folks like the one I quoted above , it's proof that you've lost any kind of original point you were trying to make , and are now looking for a good ol fashioned "internet dustup" ....

:no: Let me tell you , this board takes a VERY dim view of such provocation , and I have seen plenty of folks shown the door for hurling just the kinds of "simple mind" insults you just posted .

:thmbsp: Think about it ......

I will add the common mode fixed AC hum and thd+n high distortion is present at VOL control center tap and other end presumably from the 12AT7 First Audio AVC dual-triode > Diode plates that are parallel wired in this radio.


Including the 2 Vol.pot caps and 50C5 final beam power tube correct uF cntrl.grid cap ,

I have 4 NOS not spendy tubes shipped and ~10 discrete circuit caps with the uF # @630v values from Hayseed Ham-fest ready made made cap kit parts listing for this radio but USA name brand caps not whatever they sell there and noting new Lytics are installed in this radio anyway so pricing was more favorable this way and total $2.50 USPS .


Instead of getting stuck up for small order at Amazon, E bay, Mouser or Digikey :no:

I found them all cheap at Tube Depot store with the over priced tubes I wont buy there :LOL:D

If all that does not fix it I will jimmy rig a sig. tracer and diode detector with a Ti PDIP- 8 op amp and some buffer caps and a battery & whatever else it may I need all I probably have sine its nit tube radio stuff & I can use the Senns. HD280 phones and for the amp/tracer a capacitor /diode detector series probe for the radio sig path before AF conversion ofc with a cap uF verified that passes the AC hum and see if I can find the origination of the AC hum if it is not the bloody tube heater wire order you kindly informed me of ,they could have skewed that too , noting the 50C5 outpt. cntrl. grid cap is way wrong uF from factory ,will keep advised,

OTOH i could use my Schitt Audio Magni headphone amp it is very quiet and runs on DC wall wart .what do you think about that + diode and cap probe instead of op amp and maybe a cap on audio in to HP amp ground or no ?

full stop.

regards

You are not the VK board or a MOD and the intended to be harmless humor obviously does not suite you for some reason I don't concern myself with .

OTOH My background CAL State University education EE undergrad studies on the subject at hand may be superior to whatever you have in this electronics world so no need to jump in about the radio ,I have it covered thank you for your reply .

:scratch2: Hmm , I've seen that misplaced anger somewhere before ......

Ah Ha ! Now I remember , "Captainclock" , is that you ?

So, how bad is the hum, anyway? Every time I fix up an AA5, there's always some residual hum, I think it's kind of the nature of the beast.

I belive you crossed the line to trolling to incite others a long time ago I may report you , think about that :thmbsp:

I try to NOT TO LET ignorant trolls get to my vanity and those poor behavior mechanisms I use some times if that applies to you to you BTW :thmbsp: