Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: blown240 on December 30, 2011, 04:51:10 pm
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I am going to recap my 5G03 Zenith radio. On the cap can it lists a 60mf and a 20mf. The 20mf is no problem. But where should I look for a 60?
And does anyone have a link to a schematic?
Sorry if this is too off topic...
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(http://www.hoffmanamps.com/MyStore/catalog/images/FT32.jpg)
FT 32uf/32uf 500 volt (http://www.hoffmanamps.com/MyStore/catalog/parts4.htm)
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> 5G03 Zenith radio
1950 plastic clock-radio?
Don't need a schematic... it's a 5-tube radio, they are all the same.
The main filter cap does not have to be 60uFd, and sure does not have to be 500V like the one I pointed to. It should be at least 170V. 100uFd will be better than 60uFd. If you have defunct PC power supplies there's often a pair of 200V caps inside.
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For a "5 tube radio" google "All American 5".
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Lots of 5-tube radios used a 50uf/30uF 150V dual cap. I use 47f and 33uf replacements with 250V rating.
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Cool, thanks for the info. I am going to recap this thing and use it. Maybe add an ipod input!
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Notice there's no power transformer. If you are planning on connecting other equipment you will need an isolation transformer to avoid fires and death.
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I was just going to put a spdt switch on the volume pot. One way is am, the other is just an 1/8th inch plug for iPod.
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I was just going to put a spdt switch on the volume pot. One way is am, the other is just an 1/8th inch plug for iPod.
Cool, just make sure your life insurance is paid up first.
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Why? Sorry to have to ask, but seriously, why is it so dangerous?
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http://www.angelfire.com/electronic/funwithtubes/AA5-6.html (http://www.angelfire.com/electronic/funwithtubes/AA5-6.html)
this is darn interesting, and here is the safety info.... interesting idea about using a hair dryer cord....
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you will need an isolation transformer to avoid fires and death.
Dunno why, but that just tickles my funny bone. Sounds like something out of Get Smart. :laugh:
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Why? Sorry to have to ask, but seriously, why is it so dangerous?
DO NOT ADD IPOD OR ANY INPUT TO THAT RADIO!
the chassis can be/is at line voltage potential. you need to redesign the power supply to make it safe.
there is a reason the entire radio is covered with plastic including and especially the the knobs.
on a footnote: it's nothing i'd keep in the house if you have a curious child that likes to take things apart.
--DL
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I'd listen to DL, with or with out kids!
I like me, but I like kids more!
Brad
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This radio has the same problem that my Hammond organ had. It seems if I put a polarized cord on it and have the neutral go to the chassis, then I should be ok.
Or maybe I should just leave it as a decoration...
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This radio has the same problem that my Hammond organ had.
your hammond is/was a relatively quick fix to make safe - it has a power transformer, all you need(ed) to do is add a three wire cord and add ground path to the chassis.
this radio is different - it has NO power transformer - line current is rectified, filtered and that's it. it has absolutely no isolation form the wall power and does not have a polarized plug. when you plug it in, there's 50/50 chance that the chassis can be hot. hence why the cheap piece of shit is wrapped with plastic.
you can safety up add and isolation transfomer, a three wire grounded power cord & ground the chassis, but usually there's no room to mount it an iso tranny where is should be; in the chassis.
--DL
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OK, well I guess I will just leave it as a decoration. I have enough projects right now anyway. The wife can continue to use her little ipod speakers. Thanks for the input, once again I have learned a ton!
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just curious blown - did you read that link I posted??
hope so, here's some additional in-depth info on AA5's worth reading
http://www.geojohn.org/Radios/MyRadios/Safety.html (http://www.geojohn.org/Radios/MyRadios/Safety.html)
I wouldn't even plug it in until it was made safe.
(not trying to take anything away from the highly competent and intelligent advice that has already been given)
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Some of those plastic radios had exposed and electrically "hot" metal screws on the bottom or on the back.
The classic death was when someone used one in the bathroom and it fell into the tub....
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There's probably enough room inside to use 3 x 22/500V illinois if you don't want to use a can
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If you want to use a cap can, Antique: http://tubesandmore.com/ (http://tubesandmore.com/) has a full stock. They have, e.g.:
a) 40 20 20 -- 40 + 20 in parallel = 60; and a 20 left over; or
b) 4X 20 can. 3X 20 in parallel = 60; and a 20 left over.
With some creative arithmetic, you can use their cap cans to get just about any uF you want, with a better voltage rating than the vintage caps. Also, if necessary, a radial or axial cap can be put in series or parallel with a cap in the can to get a desired uF.
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I like to have a little tinker with valve radios...recently got into them after I picked up a few from old junk fairs etc last year.
Re the ipod link....for safety and ease, I'd just get hold of a low strength home use AM transmitter (available in kit or ready built), and then plug your ipod into that...it'll broadcast your ipod round your house (but hopefully not much further!) on AM frequencies, so then you can just tune your radio in without having to modify it. This also pleases the very an@l radio collectors out there who value originality more than guitar amp guys, and thus keeps the value intact for re-sale. The AM kit I got was this one:
http://www.vintage-radio.com/reviews/amt3000.html (http://www.vintage-radio.com/reviews/amt3000.html)