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GE 401 Tube sub question - Printable Version

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GE 401 Tube sub question - Paul Philco322 - 08-21-2022

Greetings:



I have GE 401, unremarkable but cute set I got for a fiver, cleaned up pretty well, matter of fact it was a hiddeous mess when I got it but had the feeling when clean it would look sharp, I bought for the challenge cleaning. Anyhow.....I think the rectifier is shot. While I have a few 35Z5's I have no 35W4's.



I looked in the Sylvania tube sub book but did not find a possible sub, any ideas? I imagine sometimes there is not a suitable sub. This set has a hodgepodge of tubes, use em' up they said they they did. Of course I just got a couple of needed tubes from 

Find a Tube and could have added a couple of these in for short money.



http://www.nostalgiaair.org/PagesByModel/657/M0007657.pdf


Here is mine....

https://www.flickr.com/photos/92577012@N02/38394736395/in/dateposted-public/






Ideas?



Paul

RE: GE 401 Tube sub question - RodB - 08-21-2022

If you have a 7-10 watt 240 ohm resistor you can remove the 35W4, connect the resistor across pins 3 & 4, connect a 1N4007 to pins 5 & 7 (cathode to 7) and remove the pilot lamp. I would also bring it up slowly on a variac. I haven't done this before but I know I'm headed for the same boat you're in and this is my plan when it happens. Anyone else?

RE: GE 401 Tube sub question - Paul Philco322 - 08-21-2022

I have heard that approach from some other folks, but for the cost of a couple of tubes....

My tester is a bit suspect as it gave 2 bad reports recently said they were dead and they were not, the paper rolls keep bunching up too. Have a pal who found me a new one but have not seen him since last Thanksgiving when he arrived unannounced with a tin of whiskey which I still have not had the courage to open. He forgot the tester.

So I have the other tubes, not sure about the 50C5 though, will do the old substitution routine and narrow it down, it has new caps and has played well, so think a tube.....like to think soIcon_smile. The little GE's are not bad though the speakers are kinda dull. GE 50's sets kinda bland but I have the brown companion to this they display nice, small so good to play my oldies or news, yak yak on.

Keep you posted. Thanks for the idea.

Paul

RE: GE 401 Tube sub question - David - 08-21-2022

If you do the 1n4007 set up please use a variac or you can damage the other tubes the high voltage DC will be up and running before the other heaters get there mojo going!

RE: GE 401 Tube sub question - MrFixr55 - 08-21-2022

I remember a few radios, including a Philharmonic radio / phono Ca 1947 (and it only plays 78s!) where the chassis was punched for octal sockets but wafer sockets for 7 pin minis were installed.  Some companies had marled their schematics for the octal or 7 pin mini tube and changed sockets mid run when their stock of octal tubes ran out. Even RCA did this.  Electronically (voltage drop, heater current, etc., 35W4s and 35Z5s are interchangeable.  Physically, not so much. hard to find a 7 pin plug.  Good news is 35W4s should be a dime per dozen on the Bay.

In entry level stereos and some upmarket ones, the manufacturer would run 2 50L6s (or 50C5s) and a 12AX7 in a series string but the rectifier would be solid state, therefore instantaneous.  These Units usually enjoyed a long life till the selenium rectifier blew and made everyone wanna toss their cookies (and the record player.  Same thing with the various Zenith AM FM Radios that used these same tubes and a solid state rectifier.  The bigger thing to wory about is to have some resistance before the 1N4007.  AA5 radios had no fuse, and did not need one.  The heater of the 35W4 was often the fuse, as the plate of the tube was usually hooked up to the tap in the heater.  They did this on your 401.

RE: GE 401 Tube sub question - Radioroslyn - 08-21-2022

If you don't have a resistor to replace act as the heater in the circuit you can try connecting a 1N4007 across pins 3 and 4. This will give you the 35v drop by clipping off the negative cycle of the ac voltage.

The other 1N4007 wiring (hv rectifier) stays the same.

RE: GE 401 Tube sub question - Paul Philco322 - 08-21-2022

Well this may be academic, I knew somewhere I had some more tubes, went to cellar for paper towels and rummaged around, I have 35W4 and a 50C5, can play substitution game! Thanks for the input on my simple little set. Whether large or small I enjoy listening to any tube radio......even though some certainly have better sound and tone than others.

Thanks gentlemen.

Paul

RE: GE 401 Tube sub question - mikethedruid - 08-22-2022

This is why I keep a stock of tubes. I make sure I have a complete set of extra tubes for all the radios in my collection, including 01As and WD11s. Once you start building a stock of tubes you'll find that you don't need to buy many, just the odd ones in particular sets, since you will already have the common ones. In my own case it has exceeded this. I now have hundreds of tubes, shelves full of them, and large boxes too. Needless to say, I don't often have to buy them any more, yet I still do. As for these rectifier and amplifier tubes, they are still available on eBay at fair prices. I'd much prefer to use them than try to change to solid state and have to use a variac every time I want to use the radio.

RE: GE 401 Tube sub question - Paul Philco322 - 08-22-2022

Yeah, I have a bunch of tubes, many good reasonable sources. Friend in my club a very nice fellow and a tube
salesman.he will be selling at KTown .I need to organize them a bit better, had them all the time.

These little sets sometimes have have a mix of what ever they had at the factory, once in a while something I don't have shows up.

Paul

RE: GE 401 Tube sub question - Paul Philco322 - 08-22-2022

Maybe a bad IF trfr. I did my swap, can tune over 850AM, but nothing lower. Had this before and 1 IF was shot, oh well tubecwould have been easy. Paul B.

RE: GE 401 Tube sub question - Paul Philco322 - 08-24-2022

Futzed around some more, while wiggling the 12BA6 tube got some good results, cleaned sockets for tube pins, firmly stuck it back sounded fine again, so played for ten minutes and seemed ok. Will run it for a while when I get more time. Like a simple solution.

Paul