Apex radio

[radio nut]

I just bought an early apex radio and would like help in getting a model number and a diagram . any help would be really nice. Nostalgia air only has 3 apex diagrams and they are for newer sets than mine. Thanks, Doug.318103861_tp.jpg

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[Tom Bavis]

There are a few more Apex schematics on my site: http://www.audiophool.cjb.net/RTI.html

[radio nut]

Well, I checked and none of the diagrams match up to my set. I will keep looking.

[toxcrusadr]

No tubes in it, or a tube diagram on a paper label?

[Bob E.]

It may be a home-built unit, or a kit, that used Apex vernier tuners. There are a lot of models pictured in the "Radio Manufacturers of the 1920's, vol. 1" book, but none look exactly like that. There is a reproduction of a 1925 magazine ad that has some models pictured (drawings, not photos) and the "Super Five" model looks the closest, but it is a shorter cabinet, as if you cut it off right about where the switch to the left of the left-most vernier is.

But on the same page is a reproduction of another ad for just the vernier dial, appealing to the home-brew crowd, and the caption below says that many manufacturers used them as well.

It looks like a fairly straightforward TRF set, tracing out the schematic shouldn't be too hard, especially if you look at some other sets' diagrams from the period. There just ain't a lot to them!

I have an Apex model 36 Neutrodyne set that I am getting fixed up to show at my Antique Radio show next month. It's an early AC set from 1927-28, and was about the last thing they produced before they combined with four other companies to become U. S. Radio and Television. Oh, that reminds me, there are many more Apex schematics on Nostalgiaair in the U.S. Radio and Television folder...scroll down to the bottom.

--Bob

[radio nut]

Thanks, I will check it out. I showed the set to a old time electronics nut and he thought it was a home brew.I put tubes in it and i need to figure out what batteries to use and I should be set. All the coils show resistance and the output transformers read good. The set takes 201a"s. There was not a sticker anywhere in the set to identify it at all.I am also, due to the expense of 201a tubes thinking about running it with transistors as long as that is not an invasive job. I really use my sets often so tubes for this could get pricey.

[jeyurkon]

It's just a radio and you have every right to do what you want with it, but I'd feel like I was sinning if I transistorized a set like that.

The 01, 201A tubes should last a long time. I admit they're getting pricey, but not unreasonably so yet.

John

[radio nut]

I really do understand your sinning comment, I feel the same way. I like things original, Like a car for ex., when you take a model t and put a chevy350motor, corvette suspension and other mods. in it to me it is no longer a model t. So I really want my new radio original.I guess I would be happier if there was a sub. tube that was cheaper.

[Phlogiston]

You could likely buid a transistor sub into the base of an old, dead, 201 using rectified filament voltage. Then you could just plug them in rather than messing up the radio. It would take some thinking and would not be cheeper than used replacement 201's.

[Bob E.]

I'm not sure what you consider expensive (and you say in your follow-up post that you already put tubes into the set...), but 01A's are not all that pricey, compared to some of the output tubes sought by purists. They made millions of them, and they are not that hard to find. It looks like they can be had regularly on eBay for $8 to $12 a piece, sometimes even less. And you are unlikely to wear them out on your radio or blow them up unless you do something foolish with the power supply. Jeez, you're even in Fair Radio Sales' home town, you could drive over and get some checked out ones for $18 a piece, and save on shipping! That seems like a better deal to me than trying to kludge up something with transistors in a 1920's set that was never meant to be. You can buy a battery eliminator (ARBE III) or build one from a kit (www.tubesandmore.com has one), and have a nice vintage piece to show off, rather than a Frankenstein that would not be as impressive.

--Bob

[radio nut]

Ok!!!. I get it! One thing I did not think about is my radiola 18 with a 71a output tube. Those are even more expensive than a 201a. At about 20 bucks 5 tubes seems a bit expensive, but they could be 45's or 2a3's.I am going to try and power this set up hopefully today using a 6 volt variable battery eliminator for the filaments and a bunch of nine volt batts for the b+.

[Bob E.]

You could probably use a 112 for an output tube for increased power, but you would have to play around with the voltages a bit. What are you going to use for a speaker? Or are you going to use headphones?

Before powering up, you might want to test the windings on the audio transformers to make sure there are no opens, and check the grid-leak resistor as well (should be very high resistance, like 2 - 5 megs). Otherwise you'll be hearing silence!

--Bob

[radio nut]

Thanks, I did go through it with an ohmeter and I did not find any opens. What I think is funny is the lack of components. This set has one resistor and two caps. They are air variable. It is a glass tube with a piece of rod material in each side with an air gap and they look to be adjustable. I have headphones that should work and I also have a victor "flowerpot" speaker to try. I did too much shoveling snow here so I will wait and get batts. some time this week. I am really getting excited about having a set this old working.Before I forget maybe you can help answer this question; there are 2 audio transformers, each is hooked up to a different output tube and also different headphone jacks. Is this a type of volume control?

[radio nut]

Well, I ran it today(snowed in) and I had to fix a bad solder connection. One of the tubes is shorted so I only have one audio amp. stage but it worked. Hooked up to a good ant. I picked up just 2 local stations.This set has 3 headphone jacks, the first has no audio amp. and the next one has 1 stage and then the last uses both audio amps.My headphones are about 300 ohms and I am wondering if I need higher resistance to "load" the audio tubes betterfor more volume?

[7"estatdef]

The higher the resistance of the phones the more output you will hear. The better match you will have.
Terry