the Radio Geek thread

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phil
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Re: the Radio Geek thread

Post by phil »

The Edison R-2 sounds interesting. I relate edison to phonos and cylinder players but there is an original ad for the radio here , $260.00
http://forum.talkingmachine.info/viewto ... f=2&t=3871

The broadcast unit sounds perfect for sending signal to the radio from whatever input you choose.
I have a tape machine made by Revere that has an eye tube and is stereo, sort of , it only has one speaker, to get "stereo sound' you run one side through the tape machine's amp and speaker and to get the other side you have to couple a radio and use the amp and speaker of the radio for the other side.

also have a little FM transistor tuner that you can plug a car antenna into. its quite small and I can use that in my old car which has a AM radio, but to get FM I can cheat and hide the little tuner and the radio picks up the FM signal over its antenna. It won't broadcast but I suppose I could cheat and at lest get FM to my old radios this way.

glad you found the group. we got way off topic in this thread but we have a pretty close knit community of old house lovers and this forum is doing really well and we have mick to thank for getting it up and running.

Phil

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Don M
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Re: the Radio Geek thread

Post by Don M »

phil wrote:I also have a little FM transistor tuner that you can plug a car antenna into. its quite small and I can use that in my old car which has a AM radio, but to get FM I can cheat and hide the little tuner and the radio picks up the FM signal over its antenna. It won't broadcast but I suppose I could cheat and at lest get FM to my old radios this way.\Phil


I use to have one of those FM tuners in my '63 Falcon convertible. It didn't pull in FM stations of any distance very well but it did work on the close ones.

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Jamie
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Re: the Radio Geek thread

Post by Jamie »

My Edison R2 Radio has been restored and working fine. Edison only produced radios for two years 1929 and 1930. Talk about bad timing to enter the radio market. These early sets can be a nightmare to restore. There is a bit of "hum" but Edison sets were notorious for this.
I made a holder for the "tape-mitter" and added an on-off switch for the battery. Otherwise the battery must be removed when not in use as it drains out fast. The antenna wire is wrapped around the unit for maximum reception.
Image

It is really something to listen to period music and old time radio shows over this set streamed from my computer.

Image

phil
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Re: the Radio Geek thread

Post by phil »

Jamie wrote:My Edison R2 Radio has been restored and working fine. Edison only produced radios for two years 1929 and 1930. Talk about bad timing to enter the radio market. These early sets can be a nightmare to restore. There is a bit of "hum" but Edison sets were notorious for this.
I made a holder for the "tape-mitter" and added an on-off switch for the battery. Otherwise the battery must be removed when not in use as it drains out fast. The antenna wire is wrapped around the unit for maximum reception.
Image

It is really something to listen to period music and old time radio shows over this set streamed from my computer.

Image



Yea was it /29 that the stock market crashed. when I go to look up schematics you can see data on many companies that failed around then. the surprising part was that similar to the way computers "went big" around 1995 or so, Radios did that right at the start of the depression. Everyone had to have one in their home and to this day there are many consoles manufactured in those years. Yea the depression started, but radio sales boomed!

Most radios will hum if you don't change the filter capacitors. usually large cans on top of the chassis. this is very important as often if they are put to use the capacitors short. sometimes they go off with a bang and a puff of smoke but often they can take out the power transformer as the load shoots way up when they see a short. Also these old radios had electrodynamic speakers and so a large coil of wire is used for the speaker magnet. In order to get a potential difference in voltage the radio often uses the voltage drop through this coil in it's circuit. The speaker field coil can get fried this way too. ( bad capacitors) These two parts are often specific to the manufacturer and so are difficul tto obtain , but there are certain things you can do to prevent mishaps when powering them up. I have many radios I have never tested. I only test them after changing filter caps. lots of the old sets have also metal cans under the chassis with paper capacitors inside.

hum can come from many other sources. fluorescent lights are bad. when these early radios were made the stations weren't as strong as today and often they were quite sensitive. they also did not have automatic gain control. all modern radios do. so if you do tune distant stations and then switch to strong local stations you can damage the speaker easily. sometimes hum can come from things as simple as shifting some wires around.

Most of the early radios are TRF sets. (tuned radio frequency.) The superhetrodyne circuit eventually took off and is still in use today. The early manufacturers experimented a lot and there were a lot of different ideas, some were good and some not so much. My 1929 rogers radio has a copper cup linked to a knob. it is a selectivity control and as you turn the knob it covers the tuning coil with a copper cup.

many radios won't work properly without proper alignment. I would advise anyone not to go turning screws unless they first find data on how to perform the procedure, or someone to assist. Those early TRF radios had fins on the tuning capacitors that could be bent to fine tune them. often the pot metal core warps or people straighten the fins after observing that they are bent , but not having the knowledge they are de-tuning the set.

Phil

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Re: the Radio Geek thread

Post by phil »

Tapemitter? you are coupling the signal from the tape head on a small tape player to the radios antenna ? interesting idea !

I really want one of these !
http://www.sstran.com/pages/AMT3000/overview.html

Phil

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Re: the Radio Geek thread

Post by 1918ColonialRevival »

Smart to suggest not applying power until the filter caps have been changed at a minimum. Power transformers aren't exactly cheap and it can sometimes be hard to source a direct replacement. The good thing is, if anyone is looking for a late '20s/early '30s set to use and enjoy, this is often all it takes to get it going again. Pot metal disease has been known to plague chassis of this era, particularly in the tuning mechs as you already pointed out.

To those who have early radios, it's always fun to "broadcast" period music and shows over the air for it to receive, especially since a lot of AM programming stinks nowadays. The best unit I've found for this is the SSTran, which comes in kit form. http://sstran.com/

EDIT: Looks like phil and I posted the same product at the same time!

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Re: the Radio Geek thread

Post by phil »

lots of people talk about "reforming capacitors" basically they slowly power up the set , increasing voltage a little at a time and sometimes the electrolitic power supply capacitors can be reformed. The capacitors wont' actually see power until you feed the radio about 70VAC , then the rectifier starts to work. Some will replace the ( usually 80) rectifier with a diode so that it starts to pass voltage at a lower level. at home I have a super industrial quality capacitor checker and it has all kinds of charts and data about how to reform capacitors.
I think by this stage most of the radios are so old that for me , it's a no brainer just to replace them with new components for safety and reliability. I have techniques to re-stuff the old cans and re-stuff the carboard tubes so that it doesn't change the look but you have to remove the chassis and look inside to see this so many just replace the parts and don't worry about cosmetics inside the chassis.
at minimum you can make up a dim bulb tester which is simply an extension cord with a light bulb hooked in series with one of the wires. If there is a dead short then the light bulb will glow at full intensity. Its not a perfect solution but better than plugging them straight in. You can also simply measure the resistance from one prong to the other and see if you have something close to 0 ohms, if so don't try plugging it in.

If anyone here wants to restore their own antique radio I always refer them to Phil's old radios. He has an excellent document here with references to things like how to read the value of a dogbone resistor, and how to replace the caps.

I never had formal training on tube electronics and I just jumped into the hobby and learned lots from others over the internet. The advent of the internet actually did a great service as it gave us free access to all the knowledge and data and reading material one could want. I still struggle a bit with some of the concepts but it's fun and I find I can get almost any of them going if I am determined so long as they have most of the parts.

Most schematics are available free or at a low cost. I have collected a lot of radios and tubes and knobs and parts to try to supply myself with most of what I need without a lot of purchases. Its really not an expensive hobby and once you get going it can be addictive. It's not hard to find un-restored radios and its really satisfying to restore them. once you do you can play them every day if you want. I always tell people not to leave them plugged in when not in the room though. I have never seen a restored radio go up in smoke but it doesn't hurt to be cautious.

I have no connection with Phil from Phil's old radios but he has provided a great website and this document should help anyone who wants to "put the smoke back in" their old radio so they can enjoy that old warm tube sound while they scrape paint. They really do have their own "warm sound" and at reasonable volumes they will provide many hours of enjoyment. in some of the really early (1920's) radios tubes are also collectable and can be pricey but most of the radios from 1929 or so on are not difficult to find working tubes for. Its the capacitors that fail mostly, and a few resistors but they are cheap. Speakers , coils and transformers do fail sometimes but many sets just need new caps and in most cases a workaround can be found even for those with unobtainable parts.

http://www.antiqueradio.org/recap.htm

many old radios have "eye tubes" or tuning indicators, they go dim in time, and the 1929 radios often had '45 tubes and they are a bit pricey. There is one tube used in zenith transoceanics that's probably worth 30 to 50 bucks. A lot of the radios sit in collections and are not used so we aren't' really wearing them out. tubes are like light bulbs, in that they keep well, so I don't' think this is going to end the hobby any time soon. Most of the collectors are older people so there may be some weakening of the market because a lot of the people that have attachments by early memories of them are getting to the point in their life where they aren't buying so many, of course the high end ones always hold their price just like any other antiques.

Phil

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Re: the Radio Geek thread

Post by 1918ColonialRevival »

Since capacitors are cheap, I always just replace them. I usually re-stuff mine for a more authentic appearance. The only rectifier I'll modify is a 6X5 since they are prone to shorting and taking the power transformer with it. The 1939 to 1941 model higher tube count Zeniths are especially notorious for this issue. No reason to modify an 80. It and the 5Y3 and 5Y4 were some of the best rectifier tubes made and are all still easy to find if a replacement is needed.

Phil Nelson's site is excellent and I've communicated with him several times over the years. He's a really nice guy.

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Re: the Radio Geek thread

Post by phil »

1918ColonialRevival wrote: No reason to modify an 80.


no I didn't explain well. I have heard of some people trying to reform the electrolytics in the power supply bu slowly increasing voltage to the set. The problem with that is that the set only sees power once the rectifier works and that happens way up at about 80 volts so they aren't reforming them since they won't see power before the rectifier starts to work. as a workaround one can sub in a solid state rectifier for the purpose of ramping up the power in an effort to reform the electrolytics. - and of course replace the original rectifier when done.

I agree with you. I just replace them. I might take exception if it was anything really valuable but I don't collect catalin sets. too pricey for me.. ;-)

with the paper caps I keep a tin can in a double boiler on a hotplate going half full of wax, and as I swap them I just soak them in hot wax. then i can push the guts out easily. the new caps have thin wires so usually I splice on thicker leads and hide the splices. I fill any extra space with wadded paper towel and then seal up the ends with hot melt glue. when i'm all done I give them a dip in my wax bath and they look just like they did when I cut them out.

I have pretty good confidence in the mylar caps or the orange drops. I am a bit skeptical about how long the electrolytic caps will last. Most of the sets I have done I put them inside the original cans but I am slowly rethinking whether it may be best to keep them under the chassis so they can be replaced in 20 years if my theory that the electrolytics won't last forever is correct. Sometimes it can reduce hum to keep them in the original location to avoid stray signals. I'm not sure how often that would really make a significant difference.

Phil

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Re: the Radio Geek thread

Post by 1918ColonialRevival »

phil wrote:I have pretty good confidence in the mylar caps or the orange drops. I am a bit skeptical about how long the electrolytic caps will last. Most of the sets I have done I put them inside the original cans but I am slowly rethinking whether it may be best to keep them under the chassis so they can be replaced in 20 years if my theory that the electrolytics won't last forever is correct. Sometimes it can reduce hum to keep them in the original location to avoid stray signals. I'm not sure how often that would really make a significant difference.

Phil


Most of the mylars, ceramics, and orange drops should outlive us. Every ceramic cap from the 1950s I've tested has still been fine with one exception.

You're right on the electrolytics - expect a 20-30 year lifespan before they'll need replacing again. I've worked on several video arcade games of the 1980s and I've seen so many that were bad, especially in the monitor and power supply boards, that I go ahead and replace them all like in a radio. I also won't use any that are more than a few years old in a restoration.

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