P-T125ASE
2004 Catalog
page 37
TRANSFORMER, UNIVERSAL SINGLE ENDED, HAMMOND, 3 WATT, 25 mA
Designed for general purpose or replacement use (not Hi-Fi), in single ended, tube output circuits.
Frequency response: 100 Hz. - 15 Khz (+/- 1db max. - ref. 1 Khz). (For full frequency response (20 Hz. to 20 Khz.) - see P-T1627SE).
For push-pull output use, see P-T125A - optimized for push-pull tube output circuits.
Open style with minimum 12" long primary & secondary leads leads.
All sizes use butt stacked cores (using 29M6 steel) with an air gap, to reduce D.C. core saturation.
Primary impedance range from 2,500 to 10,000 Ohms.
Secondary impedance range from 4 to 32 Ohms.
Specifications
Audio Watts: 3
Primary Impedance (Ohms): 2,500 to 10,000
Secondary Impedance (Ohms): 4 to 32
Max. DC Bias (mA): 25
Mounting centers: 2-3/8" u-bracket
Weight: 0.5 lbs.
$33.62
Qty
Thomas,
Thanks for the thorough explanation. I'm a novice at all this technical electrical stuff, so I need all the detailed help I can get to get this nice old tombstone up and running. Is there any advantage to having an 8 ohm over a 4 ohm speaker (saving battery power)or should I just look for an efficient (high SPL) speaker? I don't want to be recharging the 135 volts of batteries too often if I can help it.
Regards, Larry
Unless you have wired together a bunch of rechargable batteries, radio batteries are not normally rechargable. If you have a rechargable battery set-up, you may recharge them by making a power supply using a diode capable of at least 200 volts forward and reverse current--1 ampere, an AC cord, a 10,000 ohm resistor, and a night light bulb. Connect the 10,000 ohm resistor in parallel with the night light bulb (best to use a socket for the bulb). Connect the diode in series with the bulb-resistor assembly with the arrow on the diode facing the assembly. Connect the other side of the diode to one wire of an AC cord. The lightbulb-resistor assembly will be your positive connection. The unused wire of the AC cord will be your negative connection. The bulb will indicate when the batteries are charged. Charge for about 16 hours.
Thomas
Thomas:
Could you send me a diagram showing me how to put together a charger for the fifteen 9 volt batteries I'm going to use. I'd planned to take them apart each time they needed charging, then charge four at a time. Would I have to disassemble them all or could I leave them attached together as a 135 volt battery while charging? Thanks for all your help so far.
Regards, Larry
Thomas
Thomas,
Yes, I would like to have a diagram if you wouldn't mind putting one together for me. It would be much appreciated.
Larry
Thomas,
Another thought before you draw up a diagram.....Can I make a 110VAC to 135VDC power inverter? If so, where could I get a diagram/schematic to put one together?
Larry
I can draw you a voltage doubler circuit.
Thomas
:You could build one. You may either use a transformer that provides 135 volts AC, or you may use a voltage doubler circuit with a bleeder resistor network afterward. Using a transformer is safer (less potential for shocks to ground, though the transformer secondary can give a nice shock by itself). A transformer that provides the exact voltage you need is not always easy to find, however.
:
:I can draw you a voltage doubler circuit.
:
:Thomas
These high impedance speakers were readily available at the time. They were actually kind of obsolete due to the emergence of low impedance speakers with high strength magnets. They came before these speakers due to the need for a moving cone speaker without the availability of a high power magnet for the voice coil to work with. A weak horseshoe magnet was used instead, and the large voice coil could produce enough magnetism to work with this weak magnet and move the cone. When your radio was produced, expensive high power permanent magnets were not being used much in radio speakers yet. AC radios got around this by using a field coil which produced the high magnetism. This field coil could easily be powered off of the radio's AC power supply. In a portable radio, however, unless you want to carry around a lot of batteries, this power is not available. Since the high impedance speaker was only recenly obsolete at the time, they reverted to its use for portable radios with much success.
In this day and age, however, high strength permanent magnets are readily available, and have been since the late 1930s, though they did not take hold in the speaker market right away. To-day's speakers are only low impedance types. Low impedance speakers tend to reproduce music more faithfully for reasons I do not care to explain now (they are very technical). A low impedance coil requires a lot of current (enough to light a small light bulb of the 6 volt variety) and low voltage. Placing a resistor on your radio will reduce the voltage to the speaker, but it will not increase current. An output transformer is a special device (like all transformers) that magnetically couples a coil of many turns with a coil of a few turns. It has a special way of working like a lever say, like that you use to jack up your car. The long side of the lever will allow a lot of motion with little force. On the other side of the fulcrum, the small side of the lever will move very little, but will have much torque. These items do not translate directly to electricity, but they allow you to visualize what is going on to some degree. The large coil in the transformer takes a current with high voltage (strength) low amperage (amount) and converts it to magnetism. The small coil picks up this magnetism and creates a current with a lot of amperage (amount) and very little voltage (strength). The output transformer is specially designed to match the speaker and tube in use so it does the job magnificently well. If you were to reverse the process and send the small coil high amperage low voltage, the large coil would translate this to high voltage low amperage. This is not done with output transformers, but is mentioned so that you get the whole idea.
Anyway, as everyone knows in here, I like to get detailed, but detail is good, I guess, because then it gives you knowledge and confidence in what you are doing. At any rate, if you wish, go to Radio Shack. Ask them if they have P.A. transformers. They should still, but they are phasing out all interesting items for premade crap, so they may not. Their P.A. transformers are not too expensive if I remember correctly. This transformer will likely perform well in your radio, though it was not specifically designed to do so. Its results may not be as good as a proper output transformer, but they likely will be very agreeable (they may be as good...who knows). Use the highest primary impedance on the transformer (it will have the lowest wattage rating marked on the transformer). Connect this to your radio as the original speaker would have been. Select the appropriate secondary impedance for the speaker you are using. I must let you know that I have used one of these transformers, connected exactly as I just stated, on a Philco 60 radio (a much higher power radio than yours), and the results are admirable. The radio performs well day in and day out.
You may try lower impedances on the primary side. See how they sound. Try not to use less than the 2nd or 3rd highest impedance. The lowest impedance is really not designed for your radio. As you decrease impedance, you may get more power. Bass response will suffer, however, and the tone may be harsh. Experiment a little.
Thomas
:Well, some of the transformers aren't that expensive, either. They're only about $35. You must use a transformer, however. Here's why: Tubes are high impedance devices. That is, they are high resistance devices. They use high voltage at very low current. The original speaker in your radio had a large coil that took advantage of this low current high voltage. The large coil provided a large impedance so as to not allow the current to flow through it too quickly. I am only using this for imaginative purposes, as this is not really what happens, but it gives you a vague idea. The large coil will produce adequate magnetism with only a little current (amperage), provided that the voltage available is high enough, which it is in tube circuits. Please excuse me if I confuse you at all, as it is 2 AM, and I just got home from work.
:
:These high impedance speakers were readily available at the time. They were actually kind of obsolete due to the emergence of low impedance speakers with high strength magnets. They came before these speakers due to the need for a moving cone speaker without the availability of a high power magnet for the voice coil to work with. A weak horseshoe magnet was used instead, and the large voice coil could produce enough magnetism to work with this weak magnet and move the cone. When your radio was produced, expensive high power permanent magnets were not being used much in radio speakers yet. AC radios got around this by using a field coil which produced the high magnetism. This field coil could easily be powered off of the radio's AC power supply. In a portable radio, however, unless you want to carry around a lot of batteries, this power is not available. Since the high impedance speaker was only recenly obsolete at the time, they reverted to its use for portable radios with much success.
:
:In this day and age, however, high strength permanent magnets are readily available, and have been since the late 1930s, though they did not take hold in the speaker market right away. To-day's speakers are only low impedance types. Low impedance speakers tend to reproduce music more faithfully for reasons I do not care to explain now (they are very technical). A low impedance coil requires a lot of current (enough to light a small light bulb of the 6 volt variety) and low voltage. Placing a resistor on your radio will reduce the voltage to the speaker, but it will not increase current. An output transformer is a special device (like all transformers) that magnetically couples a coil of many turns with a coil of a few turns. It has a special way of working like a lever say, like that you use to jack up your car. The long side of the lever will allow a lot of motion with little force. On the other side of the fulcrum, the small side of the lever will move very little, but will have much torque. These items do not translate directly to electricity, but they allow you to visualize what is going on to some degree. The large coil in the transformer takes a current with high voltage (strength) low amperage (amount) and converts it to magnetism. The small coil picks up this magnetism and creates a current with a lot of amperage (amount) and very little voltage (strength). The output transformer is specially designed to match the speaker and tube in use so it does the job magnificently well. If you were to reverse the process and send the small coil high amperage low voltage, the large coil would translate this to high voltage low amperage. This is not done with output transformers, but is mentioned so that you get the whole idea.
:
:Anyway, as everyone knows in here, I like to get detailed, but detail is good, I guess, because then it gives you knowledge and confidence in what you are doing. At any rate, if you wish, go to Radio Shack. Ask them if they have P.A. transformers. They should still, but they are phasing out all interesting items for premade crap, so they may not. Their P.A. transformers are not too expensive if I remember correctly. This transformer will likely perform well in your radio, though it was not specifically designed to do so. Its results may not be as good as a proper output transformer, but they likely will be very agreeable (they may be as good...who knows). Use the highest primary impedance on the transformer (it will have the lowest wattage rating marked on the transformer). Connect this to your radio as the original speaker would have been. Select the appropriate secondary impedance for the speaker you are using. I must let you know that I have used one of these transformers, connected exactly as I just stated, on a Philco 60 radio (a much higher power radio than yours), and the results are admirable. The radio performs well day in and day out.
:
:You may try lower impedances on the primary side. See how they sound. Try not to use less than the 2nd or 3rd highest impedance. The lowest impedance is really not designed for your radio. As you decrease impedance, you may get more power. Bass response will suffer, however, and the tone may be harsh. Experiment a little.
:
:Thomas
As for the schematic, I can simply e-mail it to you if you left your e-mail address on this thread.
Thomas
Thanks, Larry
:That transformer will work. It's a bit of overkill, though. Large size and sort of high price for what you are using it for. Still, it'll work well.
:
:As for the schematic, I can simply e-mail it to you if you left your e-mail address on this thread.
:
:Thomas
:Well, some of the transformers aren't that expensive, either. They're only about $35. You must use a transformer, however. Here's why: Tubes are high impedance devices. That is, they are high resistance devices. They use high voltage at very low current. The original speaker in your radio had a large coil that took advantage of this low current high voltage. The large coil provided a large impedance so as to not allow the current to flow through it too quickly. I am only using this for imaginative purposes, as this is not really what happens, but it gives you a vague idea. The large coil will produce adequate magnetism with only a little current (amperage), provided that the voltage available is high enough, which it is in tube circuits. Please excuse me if I confuse you at all, as it is 2 AM, and I just got home from work.
:
:These high impedance speakers were readily available at the time. They were actually kind of obsolete due to the emergence of low impedance speakers with high strength magnets. They came before these speakers due to the need for a moving cone speaker without the availability of a high power magnet for the voice coil to work with. A weak horseshoe magnet was used instead, and the large voice coil could produce enough magnetism to work with this weak magnet and move the cone. When your radio was produced, expensive high power permanent magnets were not being used much in radio speakers yet. AC radios got around this by using a field coil which produced the high magnetism. This field coil could easily be powered off of the radio's AC power supply. In a portable radio, however, unless you want to carry around a lot of batteries, this power is not available. Since the high impedance speaker was only recenly obsolete at the time, they reverted to its use for portable radios with much success.
:
:In this day and age, however, high strength permanent magnets are readily available, and have been since the late 1930s, though they did not take hold in the speaker market right away. To-day's speakers are only low impedance types. Low impedance speakers tend to reproduce music more faithfully for reasons I do not care to explain now (they are very technical). A low impedance coil requires a lot of current (enough to light a small light bulb of the 6 volt variety) and low voltage. Placing a resistor on your radio will reduce the voltage to the speaker, but it will not increase current. An output transformer is a special device (like all transformers) that magnetically couples a coil of many turns with a coil of a few turns. It has a special way of working like a lever say, like that you use to jack up your car. The long side of the lever will allow a lot of motion with little force. On the other side of the fulcrum, the small side of the lever will move very little, but will have much torque. These items do not translate directly to electricity, but they allow you to visualize what is going on to some degree. The large coil in the transformer takes a current with high voltage (strength) low amperage (amount) and converts it to magnetism. The small coil picks up this magnetism and creates a current with a lot of amperage (amount) and very little voltage (strength). The output transformer is specially designed to match the speaker and tube in use so it does the job magnificently well. If you were to reverse the process and send the small coil high amperage low voltage, the large coil would translate this to high voltage low amperage. This is not done with output transformers, but is mentioned so that you get the whole idea.
:
:Anyway, as everyone knows in here, I like to get detailed, but detail is good, I guess, because then it gives you knowledge and confidence in what you are doing. At any rate, if you wish, go to Radio Shack. Ask them if they have P.A. transformers. They should still, but they are phasing out all interesting items for premade crap, so they may not. Their P.A. transformers are not too expensive if I remember correctly. This transformer will likely perform well in your radio, though it was not specifically designed to do so. Its results may not be as good as a proper output transformer, but they likely will be very agreeable (they may be as good...who knows). Use the highest primary impedance on the transformer (it will have the lowest wattage rating marked on the transformer). Connect this to your radio as the original speaker would have been. Select the appropriate secondary impedance for the speaker you are using. I must let you know that I have used one of these transformers, connected exactly as I just stated, on a Philco 60 radio (a much higher power radio than yours), and the results are admirable. The radio performs well day in and day out.
:
:You may try lower impedances on the primary side. See how they sound. Try not to use less than the 2nd or 3rd highest impedance. The lowest impedance is really not designed for your radio. As you decrease impedance, you may get more power. Bass response will suffer, however, and the tone may be harsh. Experiment a little.
:
:Thomas