Great demonstration. I'm getting an early 1930s valve radio restored and the valve radio Guru Dude alerted me to the fact that these speakers were the original fitment, so now I had to get me all learned up.
Terry I found a set of Jensen speakers there triax research tells me these might be worth thousands made in the 50s some clame them to be the best vintage speaker ever made I wish my ears could appreciate them they have crossovers with 2 pots of send pictures if I could I subscribed to ur videos because I enjoy old electronics and tube amps like you
I've long been a fan of field coils. Was actually lucky enough to find a couple inside a thrift store console a few years ago that were vintage prime. Mm ki uy🎉
Very cool... I appreciate the demonstration! I found one of these last night in an old Montgomery Ward radio that's been collecting dust in my basement for 20 years(it was my grandma's). I need to clean it up and refinish the cabinet, and I was wondering if I could use the speaker for one of my projects. Thanks for teaching me how to use it :D
Do you happen to have a model number for the power supply? I've been searching for a high voltage power supply at a reasonable cost to no avail. Also interested in the model number for the heathkit signal generator. Thanks
Ok....that’s a HealthKit?!? I have one just like it in my garage that my Dad gave me. I need to look at it again, because he must’ve assembled it in the ‘60s. Thanks!
I just bought a nonworking Philco 37-630. I was hooking up the 2 wires running from the speaker to my iPhone. I couldnt get any sound. After watching your video, I now know why. I'll try plugging the original cord into the wall to give it power, then see what happens.
Great vid, just bought me a 1948 Operadio 1A65 40watt amp, im wanting to set it up as my guitar amp, am thinking wouldn't mind getting one or two field coil speakers to match up & use. Im a complete electronics novice so any advise would be much appreciated.
So what happens if you put a modern speaker in an old radio in place of a field coil speaker, ..and conversely, what happens it you install a field coil speaker into a modern amplifier. ..? 🤷
Have a Hammond 44w amp field coil 2650 ohm The speakers are crazy expensive so i used 8 henry choke, 150 ohm and a 50w 2500 ohm resister. now i can use normal speaker.
The 44w amp (built by Leslie, used with Hammonds) did not use the field coil as a choke. It was used, however, to add a load to the screen circuit, thus keeping the screens about 36 vdc below the plates. It also effects the bias voltage. Using the choke and resistor combination you describe (or just a resistor only) is actually wasting about 29 watts of power. There is a mod you can do that will keep the screen voltage down and save the 29 watts of power, giving the amp more head room and a tiny bit more power. It involves installing a zener diode in the screen circuit and changing the bias resistor.
just enough residual magnetism in the iron yoke, or, some sort of inductive coupling with the yoke and secondary coil, ......just enough to repel & and attract the primary coil / diaphragm.
Great demonstration. I'm getting an early 1930s valve radio restored and the valve radio Guru Dude alerted me to the fact that these speakers were the original fitment, so now I had to get me all learned up.
Absolutely love that sound. I have a 10" Grigsby Grunow that I repaired it is connected to my Hallicrafters sx25.
Terry I found a set of Jensen speakers there triax research tells me these might be worth thousands made in the 50s some clame them to be the best vintage speaker ever made I wish my ears could appreciate them they have crossovers with 2 pots of send pictures if I could I subscribed to ur videos because I enjoy old electronics and tube amps like you
Good clip Terry just coming across these for the first time in an old 37-620 philco tombstone. This has helped a lot!
I've long been a fan of field coils. Was actually lucky enough to find a couple inside a thrift store console a few years ago that were vintage prime. Mm ki uy🎉
Very cool... I appreciate the demonstration! I found one of these last night in an old Montgomery Ward radio that's been collecting dust in my basement for 20 years(it was my grandma's). I need to clean it up and refinish the cabinet, and I was wondering if I could use the speaker for one of my projects. Thanks for teaching me how to use it :D
Love the sound of my old '33 Philco highboy. It has a ten inch field coil speaker in it.
Hey Terry if I do not have the specs to the speaker and I know the Ohm's on the field coil how do I determine the proper field coil voltage
Do you happen to have a model number for the power supply? I've been searching for a high voltage power supply at a reasonable cost to no avail. Also interested in the model number for the heathkit signal generator. Thanks
How does one calculate the required voltage for a FC driver. 3k Ohm FC. 16ohm VC.
Thanks J
So, if today's subwoofers had a 2nd coil, you could add or remove excursion by controlling the 2nd coil.
I wish you would have played music with it.
Really great info! Thanks, Terry.
Is it possible to replace a field coil speaker with a modern day magnetic speaker if so any videos on how to do it?
Ok....that’s a HealthKit?!? I have one just like it in my garage that my Dad gave me. I need to look at it again, because he must’ve assembled it in the ‘60s. Thanks!
I just bought a nonworking Philco 37-630. I was hooking up the 2 wires running from the speaker to my iPhone. I couldnt get any sound. After watching your video, I now know why. I'll try plugging the original cord into the wall to give it power, then see what happens.
M Harth Hello, I used a regulated high voltage DC supply for the test. Do not connect the speaker coil to AC or it will go down in flames!
Absolutely EXCELLENT vid - thanks a million :))
+sowhatdude1 Glad you like. More to follow
Nice demo!
Great vid, just bought me a 1948 Operadio 1A65 40watt amp, im wanting to set it up as my guitar amp, am thinking wouldn't mind getting one or two field coil speakers to match up & use. Im a complete electronics novice so any advise would be much appreciated.
So what happens if you put a modern speaker in an old radio in place of a field coil speaker, ..and conversely, what happens it you install a field coil speaker into a modern amplifier. ..? 🤷
Have a Hammond 44w amp field coil 2650 ohm The speakers are crazy expensive so i used 8 henry choke, 150 ohm and a 50w 2500 ohm resister. now i can use normal speaker.
The 44w amp (built by Leslie, used with Hammonds) did not use the field coil as a choke. It was used, however, to add a load to the screen circuit, thus keeping the screens about 36 vdc below the plates. It also effects the bias voltage.
Using the choke and resistor combination you describe (or just a resistor only) is actually wasting about 29 watts of power.
There is a mod you can do that will keep the screen voltage down and save the 29 watts of power, giving the amp more head room and a tiny bit more power. It involves installing a zener diode in the screen circuit and changing the bias resistor.
Why does it work even if the field coil is off?
just enough residual magnetism in the iron yoke, or, some sort of inductive coupling with the yoke and secondary coil, ......just enough to repel & and attract the primary coil / diaphragm.
Good video, but would better if you had cut off "elanor R" after about 20 seconds or so.
Interesting !!
So basically... Its the world's first form of a powered speaker
..I thought Dr. D was Kevorkian, ..no?🤷
..not Paul.
No Reply. 🤷
is this speaker related to nazis or neo nazis?