I'm building a battery eliminator for my beautiful Philco 33-37! The radio requires 5 voltages! That must have been pricey for new batteries back in the day. Well luckily I only need to build 4 voltages. I have converted my radio from, well a radio into an MP3 player! So I disabled the RF side of things and hooked up an aux jack into the chassis. So I no longer need to build 90V. But I still have 2, 3, 9 and 135V! That's a lot! Well I only have two NTE956's currently. And as the data sheet says, I can use them as a high voltage regulator as it is floating. Well I want to get that 135V without a ton of resistors. So I need the advice of anyone here on building that WITHOUT frying anything. I don't want to attempt it without help first. While the second NTE956 can go towards making my 3V supply.
But wait? How do I get the rest? Well my plan is to use a resistor to get my 2V supply. I already know my current draw for the vacuum tubes and what resistor I need. I have a 2.5ohm 5watt picked out. Need an idea on how to mount though. The 9V I will have to get another NTE956 for that. I don't have enough space inside my project box to fit a 9V battery. But it's used only for bias so I might be able to use a few resistors as a voltage divider and get it. It's only used a bias on two tubes so the current draw is not important.
I have my project mostly set up and ready for parts to be thrown in. I drilled holes to mount my connector so I can disconnect it from the radio. The only problem with that is my panel mount connector is male pins. So if someone is dumb enough to touch it with the power on they will get shocked. However, I couldn't fit it on the radio without causing too much damage. Wasn't comfortable drilling a big hole when the original wires for the battery already had a big hole. Just wouldn't fit there without the flange sticking above the chassis. Also got my holes drilled to fit my protoboard inside. I don't have the equipment to make my own circuits boards so I'm using one of those universal type prototyping boards. Also have a fuse, power switch and light mounted. Well I'm cheating. Those were already there from an earlier project.
My project box is an old Heathkit oscilloscope transformer cage. Don't worry. I only took it to pieces thanks to the post office. No need to thank them for that kind action I didn't even need to ask for!. I'll attach images of what I have so far. I won't get any of the radio until I open it to add in my wires to the power supply. Kinda a pain to do so. However this will be an awesome MP3 player! The first thing I will play out of this as it's initiation will be some Korn!
Bought the radio for only $40! I think that's a great deal! Only missing one tube and shield. And my pilot light's burned out. And all wires on the backside are torn right up. And the veneer is coming off. And the AM radio doesn't work. But who cares? It looks perfect to me! And everything so, everything appears like it will work perfect. At least I don't have to align it anymore! But I always make sure any mods I do are as easily revered as possible. So I can bring it back to the boring non Korn side of things in maybe a few hours at most.
So if anyone can provide some information on using an NTE956 aka LM317 as a high voltage regulator please let me know! I'd rather not blow one of mine up just yet! At least not while I only have two! I will for sure keep updating this for others to follow if you have a vintage battery powered radio or interested in vintage radios like me. That's Kapton tape around the transformer. It has a high voltage winding of 900V and I added heat shrink around the leads then wrapped them up in different layers of tape to prevent shorts. It ain't having a party without my permission now! The pretty sticker is mine. Added because of the last failed project built in this case. A high voltage electrolytic capacitor reformer!
But wait? How do I get the rest? Well my plan is to use a resistor to get my 2V supply. I already know my current draw for the vacuum tubes and what resistor I need. I have a 2.5ohm 5watt picked out. Need an idea on how to mount though. The 9V I will have to get another NTE956 for that. I don't have enough space inside my project box to fit a 9V battery. But it's used only for bias so I might be able to use a few resistors as a voltage divider and get it. It's only used a bias on two tubes so the current draw is not important.
I have my project mostly set up and ready for parts to be thrown in. I drilled holes to mount my connector so I can disconnect it from the radio. The only problem with that is my panel mount connector is male pins. So if someone is dumb enough to touch it with the power on they will get shocked. However, I couldn't fit it on the radio without causing too much damage. Wasn't comfortable drilling a big hole when the original wires for the battery already had a big hole. Just wouldn't fit there without the flange sticking above the chassis. Also got my holes drilled to fit my protoboard inside. I don't have the equipment to make my own circuits boards so I'm using one of those universal type prototyping boards. Also have a fuse, power switch and light mounted. Well I'm cheating. Those were already there from an earlier project.
My project box is an old Heathkit oscilloscope transformer cage. Don't worry. I only took it to pieces thanks to the post office. No need to thank them for that kind action I didn't even need to ask for!. I'll attach images of what I have so far. I won't get any of the radio until I open it to add in my wires to the power supply. Kinda a pain to do so. However this will be an awesome MP3 player! The first thing I will play out of this as it's initiation will be some Korn!
Bought the radio for only $40! I think that's a great deal! Only missing one tube and shield. And my pilot light's burned out. And all wires on the backside are torn right up. And the veneer is coming off. And the AM radio doesn't work. But who cares? It looks perfect to me! And everything so, everything appears like it will work perfect. At least I don't have to align it anymore! But I always make sure any mods I do are as easily revered as possible. So I can bring it back to the boring non Korn side of things in maybe a few hours at most.
So if anyone can provide some information on using an NTE956 aka LM317 as a high voltage regulator please let me know! I'd rather not blow one of mine up just yet! At least not while I only have two! I will for sure keep updating this for others to follow if you have a vintage battery powered radio or interested in vintage radios like me. That's Kapton tape around the transformer. It has a high voltage winding of 900V and I added heat shrink around the leads then wrapped them up in different layers of tape to prevent shorts. It ain't having a party without my permission now! The pretty sticker is mine. Added because of the last failed project built in this case. A high voltage electrolytic capacitor reformer!