RCA 222 scored - Videokarma.org TV - Video

bandersen · #1 03-26-2010, 08:57 PM

I stumbled across a listing for a Radiola 26 on the local craigslist, but the picture looked all wrong. It wasn't far away so I took a quick trip out to take a look.
It turned out to be an RCA 222!

The speaker is missing

Also, I'm not sure if the legs have been cut off or the stand was optional. I guess it's either a low, lowboy or a HUGE table top.

Checkout this thread: http://www.antiqueradios.com/forums/...45c23c0d6be727

It kinda looks like the radio is sitting on top of that little table/stand

On the positive side, the cabinet is in good shape, all knobs are there and all the tubes are the original RCA/Cunningham Radiotrons. They all test like new including the 2A5

I must confess that I know nothing about this radio. Only that it looks really cool and I'm guessing '34-'36 based on the tubes. I haven't been able to find out much about this model online.

Can anyone fill me in ?

Thanks!
Bob

jeyurkon · #2 03-26-2010, 10:19 PM

Nice!

Nostalgiaair says pre March 1934 and Radiomuseum says 1934.

John

bandersen · #3 03-26-2010, 10:41 PM

Thanks, that's a bit earlier than I thought. That image at Radiomuseum makes me think even more that the stand was a separate piece.
Maybe there's one floating around out there looking for a new home

bandersen · #4 03-27-2010, 12:51 AM

It cleaned up nicely, but really needs to be refinished sometime. There is finish loss at the edges, some veneer has separated and a few chips are missing but that will have to wait for quite some time I expect. I must finish the Westinghouse WR8 first!

Reece · #5 03-27-2010, 06:21 AM

This was about the last year for any "legged" consoles. It's not uncommon to find radios that people "modernized" back then by cutting the legs off. I suspect that's what happened here. Even so with the legs on, this was an interesting "moderne" design, the shelf underneath just crying out for some ornament. I'll bet a similar base could be made by someone with a woodshop in their garage.

Also, with missing speakers out of these old radios: I imagine a lot of boys in the 1950's saw those big honkin' speakers in grandpa's old radio stored out in the barn, and took them thinking they'd be great for their hi-fi. What a surprise when they didn't work (since they didn't know about field coil speakers needing power to the field.)

Sandy G · #6 03-27-2010, 06:40 AM

Me likey !

bandersen · #7 03-27-2010, 09:15 PM

Here are some pics of the chassis. It looks to be all original.

I think someone had a pet

bandersen · #8 03-28-2010, 04:55 AM

Even though I'm juggling way too many projects, but I couldn't resist polishing up a section of the chassis. The cadmium plating is in excellent condition

Remember, cadmium is toxic so take precautions if you're going to attempt something like this!

I've found that there's no need to clean off dirt and grime before applying the acid.

After a little acid treatment.

Now that's a purdy transformer

bandersen · #9 03-28-2010, 05:21 AM

Quote:

Originally Posted by Reece

... I'll bet a similar base could be made by someone with a woodshop in their garage.

Also, with missing speakers out of these old radios: I imagine a lot of boys in the 1950's saw those big honkin' speakers in grandpa's old radio stored out in the barn, and took them thinking they'd be great for their hi-fi. What a surprise when they didn't work (since they didn't know about field coil speakers needing power to the field.)

Good idea. I'll hunt around for some better pictures of that base and look into having a replica made.

I wonder if a speaker like this would work ? It's the correct diameter and the mounting bracket looks like it might fit OK http://cgi.ebay.com/Used-9-3-4-Field...160415947566QQ

The schematic and parts list I have don't specify the field coil or speaker impedance.

Reece · #10 03-28-2010, 08:11 AM

Wow, that chassis looks better than when RCA got done with it! Pet: at least the pet wasn't a mouse. Original: yep, the caps all look REALLY toasty and showing their age but the underside looks pretty clean. Speaker: the ePay speaker you show would have to be reconed so you'd have to add that cost in. Since he says it doesn't rub, it makes it easier. You can get cones of different sizes cheap from this source:
http://matelectronics.com/acatalog/M...ories_208.html
Only problem is they have a $25 min. order. Also these are modern cones with rubber surrounds and the old speaker might bottom out with such a flexy mount. I think I'd look around a little more and see if I could find a vintage speaker in better shape that didn't need reconing. In the meantime you could use a PM speaker for testing with a choke or big resistor ILO the field coil.

One other suggestion: it would be good to close off the bottom of the cabinet with a plywood shelf to serve two purposes: it would stiffen the cabinet, and it would provide a better baffle for the speaker. The way it is now, the back wave from the speaker has a short path around the bottom of the front baffle board and can cancel some bass from the front wave.

Sam Cogley · #11 03-28-2010, 10:08 AM

So the acid/Simichrome method doesn't damage the cadmium plating? What does it do to lettering? Where does one get Simichrome? I can't even find my old favorite polish, MAAS, around here.

Beautiful work so far. That varicap is going to be fun to clean...

I dig that Deco look. Someone obviously hacked off the legs, the wood there isn't as dark as the rest.

bandersen · #12 03-28-2010, 12:46 PM

Quote:

Originally Posted by Sam Cogley

So the acid/Simichrome method doesn't damage the cadmium plating? What does it do to lettering? Where does one get Simichrome? I can't even find my old favorite polish, MAAS, around here.

Beautiful work so far. That varicap is going to be fun to clean...

I dig that Deco look. Someone obviously hacked off the legs, the wood there isn't as dark as the rest.

Thanks!

I've used the same technique on about a dozen chassis and it doesn't seem to harm the plating. It works well on plain steel too. Most likely you will ruin any lettering. If the acid doesn't take it off, the polsih and rubbing probably will.

I got my Simichrome from Radio-Daze, but you can get it other places including ebay. A little goes a long way.

bandersen · #13 03-28-2010, 01:37 PM

Quote:

Originally Posted by Reece

Wow, that chassis looks better than when RCA got done with it! Pet: at least the pet wasn't a mouse. Original: yep, the caps all look REALLY toasty and showing their age but the underside looks pretty clean. Speaker: the ePay speaker you show would have to be reconed so you'd have to add that cost in. Since he says it doesn't rub, it makes it easier. You can get cones of different sizes cheap from this source:
http://matelectronics.com/acatalog/M...ories_208.html
Only problem is they have a $25 min. order. Also these are modern cones with rubber surrounds and the old speaker might bottom out with such a flexy mount. I think I'd look around a little more and see if I could find a vintage speaker in better shape that didn't need reconing. In the meantime you could use a PM speaker for testing with a choke or big resistor ILO the field coil.

One other suggestion: it would be good to close off the bottom of the cabinet with a plywood shelf to serve two purposes: it would stiffen the cabinet, and it would provide a better baffle for the speaker. The way it is now, the back wave from the speaker has a short path around the bottom of the front baffle board and can cancel some bass from the front wave.

Thanks for the advice. Wouldn't I need an impedance matching transformer to use a PM speaker ?

Reece · #14 03-28-2010, 03:48 PM

Yes. You'd need an output transformer. The 2A5 output tube is equivalent to a 6F6 electrically. It likes to have a 7000 ohm load. Luckily here is a site that uses the 6F6 as an example, showing how to calculate the transformer needed to operate with a speaker of a given impedance.

http://www.radioremembered.org/outimp.htm

You may have a transformer in the junk box that will work. I wouldn't hesitate to try one as it should be OK for testing purposes while you're getting the chassis recapped. Then a universal transformer intended for a single-ended amplifier should work fine as a permanent replacement. On those you can choose the taps that work the best, by experiment.

Your resistor to take the place of the speaker field coil can be about 1000 ohms, 15 or 20 watt. You might get by with a 10 watt but the higher the wattage rating the cooler it's going to run. It would have to be mounted so it wouldn't overheat any other components. Once the set's working, you could check the plate voltage of the output tube vs. a tube manual and see if it looks reasonable, or if the big resistor needs to go up or down in ohms.

EDIT: just noticed that the NostalgiaAir entry for this set shows typical pin voltage readings for the tubes: with a modern DVM, your voltages will show higher.

OK, now I'll get down off my soapbox for a while!

jr_tech · #15 03-28-2010, 07:37 PM

Nice find !

Looks like the restoration is coming along very well

"Checkout this thread: http://www.antiqueradios.com/forums/...45c23c0d6be727
It kinda looks like the radio is sitting on top of that little table/stand "

My 2cents (or less worth): For a couple of reasons, I think that "stand" was originally part of the radio and has been cut off.

1. It appears that the "grooves" on the corners of the radio continue down the legs in an unbroken pattern, except for the flare out at the bottom of the radio.
2. The "stand" would be very weak as a separate piece... note that it is braced only near the bottom, with no bracing near the top. If the legs were a part of the radio, it would be quite strong with the radio itself serving as the top bracing.

Might be fun to fabricate a replacement.

jr