[rghines1]

Here's my latest project. Found locally in the newspaper and surprised it was would show up here in SC. It's a 15 tube set from 1935 with two sets of double doors. Radio had been completely recapped around 1960 based of the vintage of the caps used. The voltages were good and found a dead 6L7 mixer. Replaced the tube expecting it play well but no go. Cranked up the signal generator and soon discovered all the calibration screws were tighten down! Following re-alignment the radio is very sensitive and selective. Link below for photos. Richard

http://s170.photobucket.com/albums/u250/...3%20radio/

[Doug Houston]

I don't know if this is the sme one i wrote some comments on in the antique radio board. But anyway, RCA is my other passion in radios, and the C15 sets fall right into the arena of preference for me. The model year was 1936, and it was the first year for metal tubes, and also the first year for tuning eye tubes. Among my collection is a C13-2, almost a C-15! The next year, 1937, had the 15k, the counterpart of the C15. In those years, the big technology race was between RCA and Philco. Zenith was a follower, but never a contender in the technology contest. Also, the 1936-37 years were the plateau of achievement for performance in radio. The next step upward came in the late thirties, with the introduction of hotter tube types for television applications, and also the loktal tube line by Sylvania. The new design innovation of the Loktals made possible better performance at high frequencies than the earlier tubes could deliver.

The initial menu of metal tubes consisted of nine types, developed by GE, and manufactured by RCA. The big advances from metal tubes were self-shielding, the octal base, and two new types, which were unlike anything previously. They were 6L7 and 6H6. The performance of metal tubes at high frequencies was marginally better than that of the fat pin tubes, if at all. In the 1936 model RCA's, tuning was set up to cover up to around 60 megacycles, and some RCA sets would get up that far, but not all of them. i have several of those models, and if they do work up that high, they will pick up channel 2 video and sound. The 6K7 in the RF stage is the determining factor.

Since RCA was in the record business, they made some very superlative record players. their 1936 line includeed the model D22-1, a phonograph combination, with a 22 tube count. The 6L7 and 6H6 made possible a volume expander for the phonograph, giving it an expanded dynamic range. The power output of the set was around 30 watts, with push-pull prallel 2A3 power amps, driving two 12 inch speakers. An example of that creation is also in my collection, and lives up to the expectations that its specs suggest. The radio receiver circuitry is the C13 design.

[Texasrocker]

Very nice RCA Rghines!! A great addition to any collection indeed! Congrats!!

As far as Zenith , just being "followers"? in 1936 , Im not so sure? Not knocking RCA, or Philco in any ways, Zenith in-fact " upped the ante" on high-tube count sets way back in 1927-29 with their TRF design "Spanish Deluxe" Large Ornate Console that resembled a Piano. http://www.radiomuseum.org/r/zenith_span...h.lat.html

Seems Zenith started the higher tube count chassis war way back then? Im not sure tho!

In 1936, Zenith introduced their "Stratospheres" models 16-A-61 & 16-A-63 respectively, both,( 16 tube sets ). Then came the grand-daddy of Zeniths (25 tube) Stratosphere mod 1000Z.

http://www.oldradiozone.com

If Zenith was dragging-their-tail, they caught-up fairly quickly!? What yr did the EH Scott ( high tube count)Philharmonics sets come out? Im not sure.

In any case, your RCA console set is Awesome RG! I had the opportunity to purchase a Zenith Spanish-Deluxe a few yrs ago locally. I passed at $6500. for a TRF!! The radio was passed-down from Conrad Hiltons 3rd Hotel ever built in San Angelo, Tx. " The Cactus Hotel". Story goes, Conrad Hilton placed a "special-order" to Zenith for the large Zenith radio for his new Hotel lobby.Several yrs later,after Conrad sold the San Angelo Cactus Hotel to new Investors in Galveston, the radio remained in the main lobby for many yrs. The Hotels mgr that stayed-on, acquired the vintage Zenith for free removal several yrs later. His son ended up with the radio, and told me he had been offered $6500. for it from a Calif vintage radio collector. I told him he better take the offer. I couldnt afford it anyway, but I told him not to plug it in until it was serviced!!

Enjoy your vintage Radios guys!!

[rghines1]

This is a new find, was not aware of another on ARF. 1936 is no doubt the correct year and was a little puzzled when two radio books and nostalgiaair schematic said 1935. Must admit RCA is not among my favorites of radio brands. The lady advertised it as a 1940s radio for $100. Called just in case the owner was mistaken, not a big fan of 40s radios. When she emailed me the pictures I was floored and did not quibble over the price. This is my highest tube count radio and first to be factory fused. Thanks for your comments.

Richard

[exray]

1936 would be the correct model year but there's good odds it was actually manufactured in 1935. New year models typically hit the market in about September of the preceeding year. Sort of like automobiles.

Nice radio and an extremely good catch!

[Doug Houston]

Radio models were like automobile models. Announcement and beginning of production was in the fall of the year previous to the model year. F'rinstance, I have a Philco 640X, that was bought new by my aunt and uncle. I first saw it in their home on Thanksgiving day, 1935. It's a '36 model set. Then, my father bought a Philco 37-650X just before Christmas, 1936.

RCA was no different than any other of the companies. Their "Red books" were published in the fall of the year when the radios came into the stores. The books are dated for the year they came out (the 1934 book covered the 1935 models!), and that was the way it went for every year.

Now, on Zenith. I fully acknowledge that there are lots of Zenith afficionados among us, and Zenith has become more of a cult than any other brand of radio I can think of. Anything said about Zenith that's not a literary genuflect, causes a flame war. More about that below.

In the thirties, tube count was the measure of radio performance. Companies, like Midwest sold radio chassis (and cabinets, if desired), riding on tube count. They usually had push-pull pparallel output stages, and two rectifiers, rather than one larger one (Wait 'til I get to Zenith!), so they stacked up a lot of tubes for the impressionable customer. Then, International Kadette broke the camel's back with a "10 tube" table model set, using as many ballast resistor tubes as functioning tubes. I understand that the Federal Trade commission, gave them a whippin' for misleading advertising.

Now, when we look at E.H. Scott, we see the most superbly engineered radio chassis in history. If a tube was required to perform a function in the chassis, it was used. Indeed, the tube count was large, but it could never have been questioned why a tube was employed. Scott was the leader in high fidelity audio, and in the 23 tube all-wave set, used Push-pull parallel 2A3 tubes in the power amp stage. You simply cannot challenge Scott's engineering and avoid being considered a fool.

Now again, on Zenith. Didn't bloat tube counts? Look at the Stratosphere. The power amp stage has eight 45's in parallel push-pull. Didn't those guys know about 2A3's? Is it possible that Zenith wanted to ace the rest of the industry in some way? Then, in subsequent years, they were well known for using two 6X5 rectifiers, instead of a single 5Y4. They also had a reputation for under-rated power transformers. Power amp stages in several Zeniths had multiple tubes in a "dynamic coupled" circuit, using a 6P5, and 6AC5 each side of the push-pull output. Nothing wrong there of course, but maybe another case for tube bloat. Zenith radios have a mystique that causes a unique affection for them. Is it possible it's because a family of farmers on TV had one?

Now, if you want to see the grand daddy of tube count bloat, look at the 37 tube Crosley "WLW" set. If you study the schematic, you'll see the silliest accumulation of tubes in one cabinet ever offered. And, the receiver section of that set is most mediocre. The circuit design of the set is nauseating, at least to me.

In 1936, Philco built their model 680, a magnificent creation. As with Scott, every tube in the set was there for a reason, and none were added just to use more tubes. The same was true for RCA, Stromberg-Carlson, Freed-Eisemann, and so on. RCA and Philco were Zenith's prime rivals. Not even Philco could surpass RCA in technological innovations, but Philco was able to stand up to RCA with Hazeltine's engineering. Zenith never pioneered anything technological, thus my use of "following". And, there is nothing wrong with that either. Zenith did make some fine chassis; good performers. I have a few in my collection, and love them. But, standing alongside Philco and RCA, Zenith doesn't stand as tall; that's all. Zenith did rise to its greatest heights in radio receivers, with its Trans-Oceanic sets. I have one of each iteration of those glorious creations, from first to last. RCA ,Philco, and everybody else were the followers there.

I understand, possibly better than most, that every one of us is differently attracted to his or her own artifact. I don't expect anyone else to go ballistic over the same stuff I do, and have done for about 65 years. Nor should anyone be vexed if I don't worship his holy grails. It's fun for me for my own reasons; that's all.

[Arran]

It's good to see that it has Sprague condensers, those are much better then the Sangamo Little Chiefs that you often find in sets overhauled in that era. I think that Sprague must have used some form of plastic film in their dielectrics since most of the ones I have tested still check out. Those are excellent sets, and are an excellent value for the money, both then and now, which is why so many of those 1935-36 series RCA sets are still around. The father of a friend of mine owned a 10 tube Canadian G.E version, I never did here it play, but always wanted one the same. He refused to turn it on since he had paid someone to get it working and was convinced that it would break if he used it. It was a sort of a bizarre circular logic, what does it matter if it works if you never use it? I guess he wasn't aware that if he did let it sit too long, the next time he powered it up it would likely go off with a bang! If he at least used it once a week it would last for years without any repairs. I loved that pinwheel flip dial that it had, hopefully I will find one for the right price one day.
Best Regards
Arran

[Arran]

Now, on Zenith. I fully acknowledge that there are lots of Zenith afficionados among us, and Zenith has become more of a cult than any other brand of radio I can think of. Anything said about Zenith that's not a literary genuflect, causes a flame war. More about that below.

In the thirties, tube count was the measure of radio performance. Companies, like Midwest sold radio chassis (and cabinets, if desired), riding on tube count. They usually had push-pull pparallel output stages, and two rectifiers, rather than one larger one (Wait 'til I get to Zenith!), so they stacked up a lot of tubes for the impressionable customer. Then, International Kadette broke the camel's back with a "10 tube" table model set, using as many ballast resistor tubes as functioning tubes. I understand that the Federal Trade commission, gave them a whippin' for misleading advertising.

Now, when we look at E.H. Scott, we see the most superbly engineered radio chassis in history. If a tube was required to perform a function in the chassis, it was used. Indeed, the tube count was large, but it could never have been questioned why a tube was employed. Scott was the leader in high fidelity audio, and in the 23 tube all-wave set, used Push-pull parallel 2A3 tubes in the power amp stage. You simply cannot challenge Scott's engineering and avoid being considered a fool.

Now again, on Zenith. Didn't bloat tube counts? Look at the Stratosphere. The power amp stage has eight 45's in parallel push-pull. Didn't those guys know about 2A3's? Is it possible that Zenith wanted to ace the rest of the industry in some way? Then, in subsequent years, they were well known for using two 6X5 rectifiers, instead of a single 5Y4. They also had a reputation for under-rated power transformers. Power amp stages in several Zeniths had multiple tubes in a "dynamic coupled" circuit, using a 6P5, and 6AC5 each side of the push-pull output. Nothing wrong there of course, but maybe another case for tube bloat. Zenith radios have a mystique that causes a unique affection for them. Is it possible it's because a family of farmers on TV had one?

Now, if you want to see the grand daddy of tube count bloat, look at the 37 tube Crosley "WLW" set. If you study the schematic, you'll see the silliest accumulation of tubes in one cabinet ever offered. And, the receiver section of that set is most mediocre. The circuit design of the set is nauseating, at least to me.

In 1936, Philco built their model 680, a magnificent creation. As with Scott, every tube in the set was there for a reason, and none were added just to use more tubes. The same was true for RCA, Stromberg-Carlson, Freed-Eisemann, and so on. RCA and Philco were Zenith's prime rivals. Not even Philco could surpass RCA in technological innovations, but Philco was able to stand up to RCA with Hazeltine's engineering. Zenith never pioneered anything technological, thus my use of "following". And, there is nothing wrong with that either. Zenith did make some fine chassis; good performers. I have a few in my collection, and love them. But, standing alongside Philco and RCA, Zenith doesn't stand as tall; that's all. Zenith did rise to its greatest heights in radio receivers, with its Trans-Oceanic sets. I have one of each iteration of those glorious creations, from first to last. RCA ,Philco, and everybody else were the followers there.

I understand, possibly better than most, that every one of us is differently attracted to his or her own artifact. I don't expect anyone else to go ballistic over the same stuff I do, and have done for about 65 years. Nor should anyone be vexed if I don't worship his holy grails. It's fun for me for my own reasons; that's all.

I did some figuring once on tube usage and figured that in terms of dealing with an AM all wave set you could pretty much do everything with every bell and whistle that you could think of with maybe 18-19 tubes, in most cases with less then that. That's with double conversion, extra RF amps, extra IF amps, volume expanders, AFC, and push pull parallel outputs. Not really any reason to add any more unless you were looking for more all out Wattage in the power output stages. Eight type #45 tubes seems stupid, like you mentioned did they not hear of 2A3s, 6A3s, or 46s or 47s for that matter?
I have to agree with Zeniths having a bit of a cult following, many seem to be gilded junkpiles built for bottom dollar to be impressive, why else would you paint a chassis and speaker frame gold? In spite of the rantings over line voltage being hard on transformers on the other forum, Zeniths seem to be the ones most afflicted by this problem, ditto with the 6X5s, none of my non Zenith radios have an overheating problem or transformers incinerated by 6X5s. But then again they had a car salesman and accountants running the company, the head of Philco was a least an engineer, a chemical one, but still an engineer, Sarnoff wasn't an engineer but he knew that it was the gateway to new markets so let them go to it. In my opinion Zenith was one of the few where their engineering and build quality actually improved after the war. Unlike most sets out there the Trans-Oceanics are one of the few that is not overrated and is sought because it was a good radio, but in the T.O's case they let the engineers do their job instead of the marketing department.
Best Regards
Arran

[rghines1]

The radio continues to work fine. Appears to have had a full restoration in the 1950s. Link below is a photo of the chassis that has the area circled where a module has been removed in the past. The Riders info doesn't help much. Anyone know? The interstage transformer has replaced in the past as well. Thanks, Richard



https://photos.app.goo.gl/8BXAynWTg8vEKZC5A

[Ron Ramirez]

It is what RCA called a "capacitor pack" containing two capacitors and two resistors. The parts are C53, C54, R23 and R27. The components are part of the set's bass compensation circuit. One resistor-cap combo connects to the "Voice-Music" switch that is also part of the on-off switch as well as to a tap on the set's volume control; and the other two connect to a different tap on the set's volume control.

See partial schematic below, also the sketch showing internal connections and color of leads coming out of the can. In the partial schematic, R24, R25 & R26 comprise the set's volume control.

   

   

The original RCA print of the schematic and under-chassis drawing was shrunk considerably to fit on one 8-1/2 x 11 inch sheet when it was originally printed back in 1935-36, so that the quality is very poor as you can see above. But this should at least help you out.

Yes, the interstage transformer is definitely a replacement. Mine fortunately still has the original, and is still working (knocking wood).

[mikethedruid]

Here is a link to the RCA Service Data manual for that period. Your C15 data begins on page 253-B
https://worldradiohistory.com/ARCHIVE-RC...1938-B.pdf

[Ron Ramirez]

Richard, since this is an older thread and your original Photobucket link no longer works (in your first post above), would you care to post a photo of your C15-3?

Let me also say that Doug Houston knew his stuff. One would do well to read carefully and heed what he had to say regarding RCA (and Philco for that matter). I don't know why Radiomuseum, for instance, cannot grasp the concept of model years but insists on listing radios by approximate date of first manufacture instead - which has only created confusion among the radio collecting community. Those who worship at the "altar" of Radiomuseum insist the first date of manufacture is correct "because Radiomuseum says so and is all-powerful and omniscient". I (and Doug, too, when he was alive) believe otherwise.

I don't own any of Doug's radios, but I am honored to now be the caretaker of his collection of RCA Red Books.

[morzh]

Wow......the thread from my youth.....when I wasn't even a member, and was still a couple of years away from being 50....and I am 60 now.


And Doug is no longer with us.


Good to meet you, Richard.

Mike

[rghines1]

Hi Ron,
Saw your thread on ARF on your RCA C15-3 and the nice job on your restoration. Congrats!
Below is a link to my "Past Radio Repairs" on Google Photos which shows the RCA and other radios. Plan to add more radios over time.
Thanks for the help and so fast!

https://photos.app.goo.gl/2tGHiY3T3GJrP298A

[rghines1]

Here is a link to the RCA Service Data manual for that period. Your C15 data begins on page 253-B

https://worldradiohistory.com/ARCHIVE-RC...1938-B.pdf

Hi Mike,

Thanks for the web site and Red Book pdf download. Went to the page on the C15-3 and appears Riders got permission to use the Red Book info. Heard of these books but that's about it.

Richard