power for radio
12/12/2009 11:52:31 PMcrism(82262:0)
i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
12/13/2009 12:00:39 AMThomas Dermody(82264:82262)
You'd have to show a schematic of the supply and of the radio, or at least make mention of what you're using to build the supply (resistors, solid state regulators, etc.). It will take more current to operate the tube filaments in parallel than in series, so depending on the design of the set, you might have to change the construction of your supply. For instance, if I were to build an AC/DC power supply using the 117Z6G tube, and I was dealing with a farm radio where all of the filaments were wired in parallel, current draw would be too great for the resistance dropping method usually employed in this kind of power supply. It would be wiser to string the tubes in series and then feed them something between 6 and 9 volts, depending on the tube types and count. Current draw would only be .06 amperes, which is easy drop through a conveniently sized power resistor. Biasing configuration in the radio would have to be altered, and this would be a rather big job. Instead of redesigning the radio, it would be better to build a more robust power supply with something like a 6 volt transformer, a full wave solid state rectifier, some large (1000+ MFD) capacitors, and a LM317 adjustable voltage regulator, which can handle up to an ampere, which is more than enough for most battery sets with 1.5 volt tubes. Adjusted for 1.5 volts, the power supply would be able to power 4 or 5 1.5 volt tubes in parallel, perhaps more.
T.
12/13/2009 12:43:48 AMcrism(82265:82264)
:You'd have to show a schematic of the supply and of the radio, or at least make mention of what you're using to build the supply (resistors, solid state regulators, etc.). It will take more current to operate the tube filaments in parallel than in series, so depending on the design of the set, you might have to change the construction of your supply. For instance, if I were to build an AC/DC power supply using the 117Z6G tube, and I was dealing with a farm radio where all of the filaments were wired in parallel, current draw would be too great for the resistance dropping method usually employed in this kind of power supply. It would be wiser to string the tubes in series and then feed them something between 6 and 9 volts, depending on the tube types and count. Current draw would only be .06 amperes, which is easy drop through a conveniently sized power resistor. Biasing configuration in the radio would have to be altered, and this would be a rather big job. Instead of redesigning the radio, it would be better to build a more robust power supply with something like a 6 volt transformer, a full wave solid state rectifier, some large (1000+ MFD) capacitors, and a LM317 adjustable voltage regulator, which can handle up to an ampere, which is more than enough for most battery sets with 1.5 volt tubes. Adjusted for 1.5 volts, the power supply would be able to power 4 or 5 1.5 volt tubes in parallel, perhaps more.
:
:T.
:
:
:T.
:
12/13/2009 12:44:23 AMcrism(82266:82265)
::You'd have to show a schematic of the supply and of the radio, or at least make mention of what you're using to build the supply (resistors, solid state regulators, etc.). It will take more current to operate the tube filaments in parallel than in series, so depending on the design of the set, you might have to change the construction of your supply. For instance, if I were to build an AC/DC power supply using the 117Z6G tube, and I was dealing with a farm radio where all of the filaments were wired in parallel, current draw would be too great for the resistance dropping method usually employed in this kind of power supply. It would be wiser to string the tubes in series and then feed them something between 6 and 9 volts, depending on the tube types and count. Current draw would only be .06 amperes, which is easy drop through a conveniently sized power resistor. Biasing configuration in the radio would have to be altered, and this would be a rather big job. Instead of redesigning the radio, it would be better to build a more robust power supply with something like a 6 volt transformer, a full wave solid state rectifier, some large (1000+ MFD) capacitors, and a LM317 adjustable voltage regulator, which can handle up to an ampere, which is more than enough for most battery sets with 1.5 volt tubes. Adjusted for 1.5 volts, the power supply would be able to power 4 or 5 1.5 volt tubes in parallel, perhaps more.
::
::T.
::
:
::
::T.
::
:
12/13/2009 7:25:55 AMEdd(82269:82266)
 |
12/15/2009 6:22:08 AMPeter G. Balazsy - Hey EDD(82339:82269)
EDD:
I stumbled on this info while googling that P-T263AX part number:
Funny that it isn't listed that way at AES?
"One such transformer is made by Hammond and is available from Antique Electronics: P-T263AX. It comes with three secondary windings: 100-0-100 VAC @100 mA, 5 VAC @ 2 A, and 6.3 VAC @ 2 A. "
12/21/2009 7:39:07 PMcrism(82577:82269)
:
:
:
:
:
:
: : : : : : : :Sir Crism . . . . . : : : : :Interim info: : : :Pending further feedback info. : : :You also didn't give the Watterson model, or tube complement, but just considering that it might be using the 1A7-1N5-1H5-1C5 series of tubes and all wired for parallel operation, that filament arrangement would be needing about 250 millimperes @ 1.4 VDC from the "A" power supply. : : :Using a 3V battery across the supply would be well on up into the danger region for those tubes, or at least a boiling / stripping off of the active chemical coating on the filaments surfaces. : : :The power supply referenced, seems adequate, in the one exception of the schematic showing an extra filament winding (7-8) :on the drawing. With the Hammond spec only showing a high voltage winding and a 5 V /2 amp winding being on the transformer. Certainly would have been a bit better if the units 5V winding was a 6.3 or 7.5 V one. : : :With that 250 mils of filament consumption, seems like the set should work, but with a set that is using greater current consumption, I can see that initial raw B+ getting pulled down so low, that there is inadequate "headroom" between the RAW DC supply, the LM317 pass regulator's loss, and the desired output voltage of the "A" supply. : : :Another possibility could be marginal capacitance from C1 or C7 due to being bad, that should show up on a ripple test. : : :A safe way to test the capability of the "A" supply would be to disconnect the radio and test out the "A" supply by the initial :measuring of the A output in your meters DC mode to confirm the units output voltage, unloaded. Looking for that 1.5VDC out. : : :Then parallel (3) 10 ohm resistors to make a 3.33 @ 1 1/2 watt dummy load and place that across the "A" supply terminals and see if the 1.5 V holds, or pulls down in value ? Also check in AC mode to confirm if there is any degree of ripple. : : :That test should confirm how well the PS is holding its output voltage at a bit greater load that your expected loading by that Watterson . .IF . . that actually is the tube lineup that is being used. : : :The 1.5 output voltage is pre-set by the voltage divider set of R2 and R1, if R1 is slightly increased in value the "A" output voltage will rise in value. : : :Of course, one needs to initially know how well the unit responds to that resistive dummy load, as well as the model of the :Watterson, so that its requirements can be more fully researched. : : : : : : : : :73's de Edd : : : : |
:
:
:
12/13/2009 8:21:33 AMjim l(82270:82262)
:i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
Hello, Sir. I have a Philco farm radio, 46-132, and I used a 6 v. transformer from a junked cassett player/recorder and used resistors to drop voltage. Oh, first used diodes to make it DC. Radio Shack [now "the Shack'] has those power adapters in different voltages alread DC output, but u probably have hum unless u used 4700 mfd filtering
Hello, Sir. I have a Philco farm radio, 46-132, and I used a 6 v. transformer from a junked cassett player/recorder and used resistors to drop voltage. Oh, first used diodes to make it DC. Radio Shack [now "the Shack'] has those power adapters in different voltages alread DC output, but u probably have hum unless u used 4700 mfd filtering
12/13/2009 9:42:28 PMjim l(82295:82262)
:i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
:My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
:My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
12/13/2009 9:44:52 PMjim l(82296:82295)
::i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
Screwes up on model # Make that 46-123
::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
Screwes up on model # Make that 46-123
12/13/2009 10:20:07 PMThomas Dermody(82300:82296)
What I said was that it would be somewhat impractical to drop 120 volts through a resistor down to 1.5 volts at 250+ miliamperes, which is why all of the 3-way portables string the tubes in series. I don't think that a 117Z6G tube could handle 250 miliamperes, and the heat given off by the resistor would be enormous as compared to a similar voltage drop at only 60 miliamperes.
However, if you are starting with a high current low voltage transformer, it wouldn't be difficult at all to drop say 6 or 12 volts down to 1.5 volts, with adequate current to draw several tubes in parallel.
T.
12/21/2009 7:42:29 PMcrism(82578:82296)
:::i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
:::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
:Screwes up on model # Make that 46-123
:
:::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
:Screwes up on model # Make that 46-123
:
12/25/2009 9:02:51 PMjim l(82646:82578)
::::i built an ac to dc power supply for a watterson radio .Radio uses 1.5 volt filament /90volt tubes .It works but 1.5 volt output of supply does not seem enough.If I parallel a 3 volt battery to filaments .It works oaky until battery drains .Any one have any suggestions..I appreciate any info
::::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
::Screwes up on model # Make that 46-123
::
:
:yes please e-mail me schematic of power supply .BTW my watterson uses the 1A7GT,1N5GT,1H5GT,3Q5GT set up.I beleive they are wired in parallel .Should i wire filaments in series .thanks
:Info: Schematic sent to Crism. Others wanting it email me
::::My SECOND comment, To u Tom and others. All I know is the A power supply I built for my Philco 64-132 works Great. Tube filaments were in parrallel---did NOT have to wire them in series. Pwr Xmfr I used already had full wave output, added correct ohm wire wound resistor to drop voltage to about 1.5 v. added about 4 1000 mfd e caps in parallel for filtering, and used the LM317 for voltage regulation. Coud send schematic Wat sa now?
::Screwes up on model # Make that 46-123
::
:
:yes please e-mail me schematic of power supply .BTW my watterson uses the 1A7GT,1N5GT,1H5GT,3Q5GT set up.I beleive they are wired in parallel .Should i wire filaments in series .thanks
:Info: Schematic sent to Crism. Others wanting it email me