This is actually an Arvin model 402 or 402A.. It dates to the 1940's. It also came in a 4 tube chassis. Yours is the model RE-55 Chassis. The 4 tube chassis was the RE-91 chassis. It was also sold as the Mighty Mite. Not a bad performer but will only pick up local stations. It was originally sold with a 20 foot antenna wire. These are easy to restore cosmetically and are neat little midget radios., You are lucky you have the back they are usually missing.
I have a four tube ARVIN from the 1950's - no IF tube - - needs an external antenna. Plastic body and a compo board back. It works fairly well. Made in the late 50's because many of it components look like cross over to transistorized chassis
Based on the Emerson CF255 from 1939. The 25B8 pentode is the RF amplifier which feeds the triode section as a grid leak detector. There is also fixed regeneration which helps with the selectivity and gain. These sets are designed to work with a specific length of aerial wire so that both tuned circuits track correctly.
here's the schematic for the radio: www.doctsf.com/documents/afficher_document.php?num_doc=6979&num_fic=1 That AF gain control is not in the audio path, it changes the bias on the RF tube cathode. BTW Arvin made a two tube version of the same radio, a 70L7GT replaced the 50L6 and 35Z5 tubes!
On the midget Arvin: Those who said this is a TRF set are correct. There's a small amount of regeneration to tighten up the bandwidth some. It seemed like a reflex set, but no. Those were covered some in the early GE Transistor Manuals. On HD Radio: HD has nothing to do with high definition, as we heard. HD stands for Hybrid Digital. On FM the bandwidth is there to allow for higher bitrates and multiple audio (and revenue) streams. You can see the blocks of digital carriers either side of an FM station on the waterfall of your SDR. On AM, the narrow bandwidth analog signal is actually preferable, unless one is into listening to audio thick with aliasing and other digital artifacts. A good hi-fi AM tuner sounds much better by comparison.
Two-section tuner, but the two sections are the same size. No antenna tuner / oscillator section like a superhet. That's a TRF. That 25B8 is a pentode and a triode in the same envelope. Very cool radio.
I made a 2 transistor radio with very few component and little knowledge of electronic when I was a teenager, the radio was working good, laud and clear, that simple homemade solid state portable radio was able to receive local stations without selectivity, just like that bulky yours, which reminds me then over 50 years ago, I wish I had that radio back as a part of my tangible memories.
Amazing !! One 50L6 radio bulb and the radio device works !! Perfect charge up of the main filter Cap thru the 40 Watt ballast capsule. That is an awesome find for 10 bucks.
The hd sounds compressed for sure on the am side. Remember am stereo in the older cars? It had a very warm sound. My dad had a am fm with am stereo in his olds. Your hd radio is a joke next to that really cute metal tube radio. Anyway I love hearing am sound on older tube radios as well as the older cheap transistor radios. Maybe I will pick up one of those cheap hd radios for the fun of it. Sirius XM is what I listen to most of the time for listening for a wide range variety of muzik. But love your radio. Have fun with it. Take care, Gary S.
It is amazing that this little Arvin could achieve so much sensitivity with a single tetrode RF stage. However, one of the drawbacks of TRF technology becomes apparent as Shango scans the dial; selectivity is much sharper at the bottom of the dial than at the top. JW Miller once came up with a special RF transformer set and matching four-section variable capacitor for use in a high-perfomance TRF radio (the Miller 570). The transformers employed a special coupling arrangement to maintain a nearly constant bandwidth, regardless of where one tuned the radio. However, these parts were not cheap! Lastly, I will say that something in your home is re-radiating AM broadcast band signals. I have noticed that in many of your videos, KFI and KNX have a lot of powerline hum riding on top of them. Have you attempted to use a portable radio to locate the source of the interference?
Ahhhh HD radio is much like you are right there. Nothing beats the good old stuff though. Our grandkids will look at us like whats HD radio lol atleast with the good old stuff we have something to show them.
There's a video he's got on a 1935 radio that worked out of the box as well, nearly 100 years old and it still works fine and dandy. A bit weak, but excellent for it's age nonetheless. Maybe not one bit, seeing as parity and correction are a thing, but in theory lose a few bytes and you're screwed.
Great to see that little old radio come back to life. not bad for its age. I wish we would have something like HD radio here. Like I already commented on your first HD radio test video we have digital radio, but it's on a totally different frequency band and the coverage isn't that great...and there are plans to switch everything to digital so millions of analog FM radios would become useless. I like the idea of HD radio doing it in a "hybride" way...so it's still the same frequency, the same transmitter and you can listen analog or digital...even on AM...that sounds cool to me!
I did a little bit of work experience in a radio station (news room) a few years ago. One story they tried to keep sneaking in was how much better digital radio was supposed to be. Well a few years down the track, and it still doesn't have that much of a foothold in the Australian market here either. Complete and utter waste of resources.
If you replace all of those wax caps that will help with the channel bleed over. All of those wax caps have moisture issues with age and get leaky. I actually slice the wax sleeve lengthwise and pull the guts out then wrap the sleeve around a modern axial cap, put the cut end inward towards the chassis, then they look original. The same things can be done with the filter caps, carefully pry the "can" off of the cap "base", solder modern caps into the base, then crimp the can onto the base and it will look original too. All depends on how much you care about keeping the antiqueness of the unit.
I have a 4-Tube ARVIN breakfast-tabletop radio that is superheterodyne, with AVC! It needs a lengthy aerial to pull in a few stations. The trick to getting its cost and chassis size down was to remove the IF amplifier stage entirely. It even still has its original back cover
The buzzing can / could be from people using LAN BPL (Local Area Network Broadband over Power Line) extenders, those things you plug into the outlet and then plug in your PC LAN cable to use the house power lines as part of the LAN network. If ONE person on your section of the grid (your neighborhood) has one then you will hear the buzzing it generated on the AC line. Another cause can be WAN BPL (Wide Area LAN, Broadband over Power Line). I don't think this is used in the US by consumer ISP's yet but more so by power/utility companies to give workers internet access in rural substations and so on so they can communicate directly back to the home offices. You would think the FCC would man up and step in and do something about this though but it only goes to show how much they actually care about inferior radios bands...
That chassis looks almost like the radio that Rocky turns on when he gets up and drinks a glass of raw eggs before he gets ready to go running in the 1st Rocky movie lol
Interesting the way the US does their "HD radio". It's piggybacked on the normal AM and FM signal. Here in Australia we use a system called DAB+ (Digital Audio Broadcasting Plus) which is AAC2+ and broadcast on a completely different frequency whereby we have 50 or 60 stations all on an old analogue TV frequency at around 200MHz. Thanks for the video as while I've been to the US many times I've never realised this is how HD radio worked over there.
+vk3crg HD Radio can be mixed with the regular signal or even broadcast on a separate tower. It rides along the sidebands of an AM or FM station. It uses a proprietary version of the AAC+ codec. The upper and lower sidebands transmit redundant data to reduce the error rate. An FM station can send 96 bps. Most stations break that in half to send a digital version of the station plus an additional HD-2 station. This gives audio quality somewhat better than FM with higher dynamic range and frequency response (analog FM is cut off at 15 Khz). Some rare stations (mostly classical) use the entire bandwidth on their staton and that gives incredible sound quality, definitely approaching CD quality to my ears. The main reason I listen to it is no multipath. Where I work most FM stations are buzzing crunching messes but HD Radio has no problem getting through.
I don't know I recall a neighbor on the farm had one of those in his line shack where the sheep herders stayed when the sheep were in pasture. Perhaps his was a 4 tube, I don't know but same size and it got quite a few stations. Of course he did have a long wire antenna running from the shack to the windmill.
It was a pity that the battery case was such in disorder, otherwise it was good working and I liked particularly the socket transistor system at hat was used by the early portable zenith radios. Thanks for the demonstration. I would have liked to see a "second"film on it.
hi I'm really glade your stillon youtube I really like your vidieo man I'm learning a lot guy radiotvphononut I see his video about what happen I'm just glade your still on keep it up thanks
That radio is cool! I believe it is a single stage superhet convertor with no IF system - looks like mixer-oscilator pentode drives detector/AF amp triode. You would get conversion gain from the local oscillator. I'd like to see a follow up video with a scope using 10X probe on each of the gangs of the variable cap to see what LO frequency is for a given RX frequency.
between 1998 and 2000 i had a 1928 or 1929 atwater kent trf radio. actually they called it a regenerative receiver but i bellieve that is basically a trf. i was told it was the first ac set atwater kent made. all i had to do to it was change the output tube and it worked perfect on all origional components the whole time i had it. no volume control though you controled the volume by varying the filament voltage. worked great but my neighbor hated it because no avc so it got loud all on its own when changing stations or with variation in signal strength.
+No Name yes my radio definitely wasn't a hot chassis set had a huge power transformer and the filter caps rectifier tube etc on a separate chassis from the radio. if memory serves it had a bunch of 29 a 45 and an 80 tube. haven't seen the radio in years so i could be wrong about the tube complement. it was the first and last radio i had from the 1920's.
AK went out of business for a lot of reasons, mainly the 1929 crash and it's effects. However, you are somewhat correct. They refused to "cheapen" their product to reduce prices in a time when that was obviously good for business. They did eventually do that somewhat, but it was too late. There was really no such thing as a "cheap" Atwater Kent radio. Hot chassis sets were still a few years from production when AK went under. They did make a few resistance line cord sets, though, for cost reduction. Probably too late in the game.
AK closed his factory in philly because he saw RCA among others "cheapening" up(nothing in the day was truely cheap as in todays terms) and he said flat out that hed rather close his factory than use anything but the very best. He let his crew go paid them and locked up never to return. Thats a man that believed in QUALITY and thats why his sets even the tombstones of the 30s are still around. Mostly original
There may be a bad transformer, or insulator, nearby in your power network. I have noticed from driving along side primary leads while listening to an AM station in a car, that sometimes I would hear a localized, pronounced low frequency interference or higher frequency arcing/static that is most likely caused by an issue to either of the 2. Maybe a walk around your power lead with a handheld AM radio tuned to the bottom of the band but off station might help you to localize the issue, but good luck getting the power provider to do anything about it.
"it's all metal" You will for sure know if it ever develops a short 😂 but looks to be very good build quality! and probably rare compared to the common AA5 radios.
Aqui em casa tinha um radio assim mas acaixa ers de madeira e ele era ah transistor o meu tio tinha um radio do mesmo modelo e era valvulado! Rio RJ Brasil
I've drilled a small hole in sealed pots and throwed the juice to them lol 😁 it works quite well. But it's best to use a small hand drill that you twist. Using a power drill I would not recommend.
That was a surprise it worked! The 3 tube radio is a TRF and by this time you probably found out the 25B8 is a combo tube, Pentode and Triode.... Just like AM stereo had a falling out of favor with the public, here the one local AM station doing the HD, also turned off their HD IBOC digital broadcasting, I'm so glad they did. IBOC should never have been implemented, as it ruined reception of adjacent stations. Last time I checked, only a couple of distance stations at night time are still broadcasting the digital HD IBOC crap. Another failed miserable attempt to upgrade AM.🤔
I have similar buzzing in the UK but only at night. It comes in on the neutral line and I think it's poor power factor correction on discharge lighting in the area.
Have you ever played around with C-QUAM AM-Stereo? The local AM oldies station 740 WDGY recently dropped their AM-HD signal in favor of C-QUAM. Nice score on that 3 tube set. Almost looks like an Arvin. I have a little metal cabinet 4 tube Airline model 84KR1520B. Metal cabinet and a hot chassis...
I like the styling of the radio, but jeez a metal case and a hot chassis. The radio looks very compact, but that has made for a very crowded layout of components under the chassis. I commend the use of the lamp-limiter. The higher the wattage of the bulb filament the less it restricts the current flow to the radio. I know you are well aware of that, but just in case others are curious. I am very surprised the radio works at all. The waxed paper capacitor is notorious for going electrically leaky & that radio is full of them. The B+ filter capacitors are also often dried out. If the performance of the radio is probably not going to be good enough for everyday use, you have to consider whether it is going to be best left alone.
Interesting, in the Uk we have digital radio, but its not in the form of sidebands on an analogue signal, we have dab, digital audio band, which is all digital on around 200mc's. Analogue radio here was scheduled to be taken down a couple of years ago, but for some reason, probably because so many still have analogue radios it was postponed for an undetermined period, so for now we still have sw, am and fm, tv is all digital. I liked your vid on the ferguson console, I had a bush console which looked like the same chassis.
UK might not have AM much longer: Absolute shut their MW transmitters, BBC R4 LW will be gone by March 31st and in 2026, they're shutting down 5Live on MW.
These were among the cheapest of radios, mainly intended for use in large cities with lots of local radio stations. No IF transformers, no AVC, and quite a bit of regeneration, so iffy at best. I have one like this that even has a 6E5 eye tube where the eye tube has audio going through it. Very clever but marginal design. Didn't catch on.
There is a difference between FM and HD our Classical station where I live even with a strong signal has some noise you can hear in very low passages. When it switches to HD all the noise goes away!
I'm not an expert, but based on a cursory internet search I am going to guess that it is a Kent model 402 midget radio from 1939. Supposedly there was also a 2-tube(!) version using a 70L7 and a 25B8. It would be interesting to understand the set's theory of operation. Especially the 2-tube version.
The three tube radio did you go through it,and if so do you still have it ,I would love to buy it from you .another great video ,I like the stuff you find and repair .
That 25B8 is a triode/pentode, as I recall. TRF set, I imagine. Guessing late '30s early '40s. Check out Arvin 402, 402a--chassis RE-55. Nostalgia Air will have schematic.
That 25B8 is a triode/pentode. That could be a superhet with the pentode as an autodyne converter, and the triode as a detector, no IF amp stage. If it is a TRF, the pentode would be an RF amp, the triode a detector, and the Pentode could function as a reflex af stage. When I was a teenager, I built a one tube radio that could drive a speaker. It had a 12AU7 that functioned as a detector / af amp and on strong stations would drive a 4" speaker. Used a selenium rectifier, and a 700 ohm 20 watt resistor in series with the heater. Wasted 20 watts just on the filament! I hope you were using an isolation transformer to test that. Or were wearing thick rubber soled shoes! Might have to drill a hole in the volume control to spray clean it. Or just replace it.
Interesting, first time I've heard "HD" radio as I think Australia doesn't have the broadcast technnolgy that's in America, I think there were plans for it but it simply got forgotten about. We still use AM/FM bands though.
@@charlesdoroszlay5370 bro I don't even remember making this comment, but there's always also been radio being broadcast on whatever we use for digital tv signal
You guys have DAB and something like Freeview and Freesat in the UK where your radio is available on Free Over-the-Air or Free Satellite TV, it's a World apart from how we decided to structure our digital radio format in the US (and some in Canada and Mexico).
About the digital AM radio; I'd never heard it till now. And that's as good as it sounds? You're right, it has a lot of aliasing; doesn't sound all that great! If that's as good as HD AM sounds, I'd rather listen to analog AM.
The 3 the condenser trf. Better of 30s trf has better am high frequency response .need a wire to Mexican wall for ant . Amazingly it works the key is both tuning condenser same size . I have a philco cathedral 20 is trf and it's later superhet brother both work about same 😎
Long wire? it was built when we didn't have too many stations. Ps a filter at about 455 will help. The tube rig. Used to have one at the mod center LIma ohio. The radio was forgotten by a NCO. that had a spot I took over. Parts/ tubes gotten from fair radio. LIma ohio. Radio station was wima.( 1150) there hi hi
I have two digital radios one is a Morphy Richards 27024 SDR multi band radio LW/MW/FM/DAB/DRM the other is a Technics ST-GT1000 LW/MW/FM/DAB (DRM is Digital Radio Mondale) not Digital Rights Management, is FFT used to decode the sub bands into Audio as they might have used a IFT to convert the audio into a IFT which that use to generate the sidebands for the HD radio that is how it is done in DAB, DRM does it an other way not sure how.
