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voltage on tube heater 46-350 - Printable Version

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voltage on tube heater 46-350 - mountain man - 02-02-2013

newbie here got the old girl working by recapping and replaced rect tube am concerned about the voltage diff from the 40 till now should there be a problem with raising the voltage from 115 to 120? i figure it may be hard on filament heaters Icon_crazy


voltage on tube heater 46-350 - Radioroslyn - 02-03-2013

Hi Mountain man and Welcome to the Phourm!
Wouldn't lose any sleep over the filament voltage. (Tubes with a cathode have a heater. Tubes without a cathode have a filament).Some of those 1.5v tubes have to run with 1.5v or a little better especially the 1R5. If you have any other questions you may want to start your own thread on the matter. It will be a little less confusing. Tnx for stopping by.
GL
Terry


voltage on tube heater 46-350 - mountain man - 02-04-2013

thanks for the info Terry it was just that the schematic shows 8.4 on tube heaters and at 123 vac this number is over that voltage considerably.


voltage on tube heater 46-350 - mountain man - 02-04-2013

Concerned about the higher operating voltages from 1946 110 to 2013 123vac in my area, this will raise heater voltages over 8.5 volts, I read that a power resistor may be in order, what type and size? also on alignment procedure it calls for an output meter to be attached to speaker terminals is this a volt meter?


RE: voltage on tube heater 46-350 - Conelrad - 02-04-2013

Resistors can be used to counter high line voltages, but either a bucking transformer or Variac mounted separately is a more efficient idea. Neither of them produces the heat as a resistor in the job would.

Any AC voltmeter with appropriate range can be used as an output meter, as you are just reading audio levels on the output, after using a tone modulated signal generator to accomplish set alignment.

Dennis


RE: voltage on tube heater 46-350 - Radioroslyn - 02-04-2013

To add to Dennis's comments you probably want to use an analog meter just easier to read. It will be set on the low setting for AC volts.
A bucking transformers an easy way to knock down the line voltage.
GL
Terry


RE: voltage on tube heater 46-350 - Arran - 02-04-2013

I still say this 110 volt line voltage idea is a myth, unless you are dealing with DC power grids, most radios from then were calculated around a working voltage of 117 volts at least as the line voltages could very between 105 and 125 volts. If the line voltage is 123 volts that's still a little high but 6 volts high not 13 volts high. Bring it down to around 115-117 and it will be fine.
Regards
Arran


RE: voltage on tube heater 46-350 - mountain man - 02-05-2013

does anyone have any information on component locations I see on the schematic "C"#'s. it would make alignment and part id a whole lot easier.


RE: voltage on tube heater 46-350 - Ron Ramirez - 02-05-2013

Mountain man

Contact Chuck and get the entire package of service info for your set, it will save you some headaches.

http://www.philcorepairbench.com/schematics.htm


RE: voltage on tube heater 46-350 - mountain man - 02-06-2013

Thanks Ron, also I am looking at a 20 ohm 25 watt power resistor to knock down the line voltage, any thoughts?


RE: voltage on tube heater 46-350 - Ron Ramirez - 02-06-2013

Mountain man

As Dennis (Conelrad) and Terry (7estatdef) have mentioned, a bucking transformer or Variac would be a better way to reduce the line voltage if you are determined to do so.

Google the phrase "line voltage bucking transformer" and you should get several results on how to do this.

Also, please do not post about the same subject in different threads. This only results in confusion. I have merged one thread with posts on the same subject from another thread into this single new thread, to keep it all together.


RE: voltage on tube heater 46-350 - mountain man - 02-06-2013

sorry just trying to get the hang it, please forgive my ignorance


RE: voltage on tube heater 46-350 - Ron Ramirez - 02-06-2013

Don't sweat it, we're here to help. Icon_smile


RE: voltage on tube heater 46-350 - TA Forbes - 02-06-2013

If you do use a resistor I would opt for something in the 40 watt range.


RE: voltage on tube heater 46-350 - codefox1 - 02-06-2013

Yeah, would be nice to slim the voltage to filaments a bit with bucking transformer or resistor. Not going to lose much volume and might get another year or three from tubes.