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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Fri 04, 2005 8:12 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1034
I have a Radiola 20 that someone has replaced the original 199's and 20 with 301's and a 71A. I can only assume the replacements are easier to come by than the originals.<P>After adjusting for the differences in the voltages --filament, plate, bias--the radio works, but is very touchy. Would it be more stable with the original type tubes?<P>------------------<BR>


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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Fri 04, 2005 6:40 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 31406
Location: Livermore, CA
Hi Lyndell<P> Those 01A's draw a lot more filament current. Radiola 20 uses filament rheostats more like wire wound resistors. With high currents these controls will be touchy. They are probably also getting warm?<P> Better tubes to sub for 99 is #30 and for 20 use a #31. (2 volt tubes) These are much closer to originals and will have smooth operation of the rheostats.<P>------------------<BR>Norm


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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Fri 04, 2005 9:45 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4981
Location: Wilmington, NC 28412 USA
Just sold a 20 that had all 30 tubes in it. The Paper work with it . Said 2 changes had to be Made. The Reostat for the Filament Voltage AND the Volume pot.<BR>Hope this helps<BR>JB<P>------------------<BR>


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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Sat 05, 2005 7:38 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Thanks,<P>I will replace with 30s and see what happens. <P>------------------<BR>


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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Sat 19, 2005 10:22 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 29
Location: rhinelander wi usa
hi lyndell, i have a radiola 20 i modernized with #30 tubes by a method i found in some old rca service bulletins. this works for 2 and 5 volt tubes. open the leads whic run from the center tap of the rf coils to the c battery .and insert 100,000 ohm carbon resistors. i have done this and the set works quite well. bill jelinek<P>------------------<BR>


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 Post subject: Tube substitutions in a Radiola 20
PostPosted: Mar Sun 20, 2005 7:06 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1034
Hi Jelin, thanks for the suggestion, but the radio is now on its way to Italy with a set of 30 and 31 tubes.<P>------------------<BR>


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