So glad that folks are still checking out this video 📞(and hopefully making their own lo-fi microphones). You can check out more hands-on audio electronic projects here: th-cam.com/play/PL7w4cOVVxL6F_MAwxOJbq73HXdG0OjdXn.html&si=_XQPAsQ1lX0wRF3O
Thank you for showing your whole trial and error process. Its super helpful to see someone working through a process i stead of just being told how to do sonething!
That's a newer generation CD-500 phone. The originals had a rotary dial and the TT version the keypad and board were one piece with coils used for the oscillator. I don't know if your version reacts the same, but you can generate a single tone by holding either two buttons down in a row or column. There was a book published of TT songs you can play on the keyboard.
Glad you like them. Yes! They're certainly little adventures for me. In reality these all take a bunch of hours, so be glad I only share the abridged versions.
Boy, that's a good question. I'm not sure. The microphone part (the carbon mic that I make in this video) I think would be high impedance, but if you (mis)use the earpiece as a microphone, I think it would probably be low impedance, since, as a speaker, it designed to be low impedance. I'm happy to be corrected if anyone knows for sure!
Good question! I've had these in my drawer for a long time, and they were some cheap eBay purchase. The only hint is, on the bag it says 500ct/8ct (in my handwriting). Really, though, I think almost any audio transformer should work. (An electrical engineer can correct me here, but the purpose of the transformer in the circuit is to remove the DC offset, the direct voltage from the 9V battery, right?)
@@brianzditowski6431 Seems like I need to look for the transformer you are using for a 1931 studio double button carbon (Universal Microphone Co.) I have even installed new carbon.
Hmmmmmmmmmmmmmm.... My short answer is: I don't know. For a slightly longer answer: So, the 9V battery is in the circuit, right? Without the transfomer, you'd be running the 9V into your mic preamp, mixer, or audio interface. Now, I believe most audio interfaces are "DC Blocked" so this might not matter, but I really don't know for all those other systems. It's only 9V, but still, I wouldn't want you breaking any of your equipment! Is there an electrical engineer out there who can answer this question?
Putting the output jack in parallel with the powered mic circuit, and with a capacitor in series with the jack should also work to block dc voltage(depending on the capacitor value, this will also act as a highpass filter)
Oh, one more question! I want to wire both the ear piece and mic to be microphones with a switch to toggle between the two. I'd like to put the switch on the headset, but the easiest way to wire it would require the voltage to go through the earpiece mic as well. Would this cause any issues? (In short, can I run a 9v voltage through the passive speaker mic?)
Hmmm. It's probably not good to send that 9V to the earpiece mic/speaker. Like, at the very least, the voltage will be pushing out the speaker, so it would have to vibrate with incoming sound while dealing with that voltage. You might not get any sound at all. It seems like you might be able to wire your circuit in a way that your switch won't send the voltage to the earpiece mic/speaker.
So glad that folks are still checking out this video 📞(and hopefully making their own lo-fi microphones). You can check out more hands-on audio electronic projects here: th-cam.com/play/PL7w4cOVVxL6F_MAwxOJbq73HXdG0OjdXn.html&si=_XQPAsQ1lX0wRF3O
Thank you for showing your whole trial and error process. Its super helpful to see someone working through a process i stead of just being told how to do sonething!
Thanks for watching! Glad to hear that you appreciate the process and journey!
That's a newer generation CD-500 phone. The originals had a rotary dial and the TT version the keypad and board were one piece with coils used for the oscillator. I don't know if your version reacts the same, but you can generate a single tone by holding either two buttons down in a row or column. There was a book published of TT songs you can play on the keyboard.
Cool! Great to know. Thanks for sharing your expertise!
I could watch these videos all day. They're like little adventures. (Additionally, you make a mess exploring these items' innards so I don't have to)
Glad you like them. Yes! They're certainly little adventures for me. In reality these all take a bunch of hours, so be glad I only share the abridged versions.
I’ve recorded those bells into songs. I can’t remember the notes they produce, but if it’s in key with the song it can be used.
this is so awesome thank you for documenting this adventure in electronics!
Glad you enjoyed it!
Insanely awesome
Nice video. I would like a schematic. Thank you.
So using the ear piece as a microphone what input would you hook it up to, hi imp. or low imp.?
Boy, that's a good question. I'm not sure. The microphone part (the carbon mic that I make in this video) I think would be high impedance, but if you (mis)use the earpiece as a microphone, I think it would probably be low impedance, since, as a speaker, it designed to be low impedance. I'm happy to be corrected if anyone knows for sure!
Awesome build, dude! what kind of transformer are you using there? Thanks!
Good question! I've had these in my drawer for a long time, and they were some cheap eBay purchase. The only hint is, on the bag it says 500ct/8ct (in my handwriting). Really, though, I think almost any audio transformer should work. (An electrical engineer can correct me here, but the purpose of the transformer in the circuit is to remove the DC offset, the direct voltage from the 9V battery, right?)
@@SimonHutchinson Great! clearly explained! I have some carbon mics in a box so I want to try build one! thank you for the info! cheers!
@@brianzditowski6431 Seems like I need to look for the transformer you are using for a 1931 studio double button carbon (Universal Microphone Co.) I have even installed new carbon.
Can I do that without transformer
Hmmmmmmmmmmmmmm.... My short answer is: I don't know. For a slightly longer answer: So, the 9V battery is in the circuit, right? Without the transfomer, you'd be running the 9V into your mic preamp, mixer, or audio interface. Now, I believe most audio interfaces are "DC Blocked" so this might not matter, but I really don't know for all those other systems. It's only 9V, but still, I wouldn't want you breaking any of your equipment! Is there an electrical engineer out there who can answer this question?
@@SimonHutchinson thanks for responding
Try using a 1.5v AA battery!
Putting the output jack in parallel with the powered mic circuit, and with a capacitor in series with the jack should also work to block dc voltage(depending on the capacitor value, this will also act as a highpass filter)
What kind of transformer did you use?
I tried to use the transformer that came inside my phone, and it worked, but I got lots of strange static buzz that came and went
Oh, one more question! I want to wire both the ear piece and mic to be microphones with a switch to toggle between the two. I'd like to put the switch on the headset, but the easiest way to wire it would require the voltage to go through the earpiece mic as well. Would this cause any issues? (In short, can I run a 9v voltage through the passive speaker mic?)
Hmmm. It's probably not good to send that 9V to the earpiece mic/speaker. Like, at the very least, the voltage will be pushing out the speaker, so it would have to vibrate with incoming sound while dealing with that voltage. You might not get any sound at all. It seems like you might be able to wire your circuit in a way that your switch won't send the voltage to the earpiece mic/speaker.
Oh sorry. Just saw I missed this question. I think I talk about the transformer in another comment here.