Just finished building a similar set using a 1Q5GT instead of a 12AU7. I also used an LM386 to drive a loud speaker. But the "magic" is in the front-end. The sensitivity and selectivity of these regenerative sets is just amazing!
Peter, thanks so much for your generosity in time to reply on your live stream!!! This is a fantastic project !!! Valves are large and easy to understand, using low voltages is even better! Keep the simple but amazing projects coming please 🙏
Incredible! I never thought valves could run on such a low voltage, I know some transistor circuits that cant run on 12 volt. It sounds pretty good from what i could hear thought the camera.
Yeah Dave very pleased with how it turned out. Want to put it into a proper case and add some extra bands: ideally 0.5 - 2, 1.6 - 4, 3.5 - 7.5 & 7 - 20 MHz. SSB should be acceptable up to at least 40m. Not all valves will apparently handle low HT, and anything that needs some power (eg an audio amp) is unsuitable. But that's what ICs can do well.
It appears that the radio uses a Hartley Oscillator as a detector. I have used a electron-coupled Hartley oscillator as detector in my TRF experiments. However, I should say that I have been using the big coke bottle Octal valves and 250V HT. A solid-state output stage would certainly eliminate the problem of RF getting to the audio stage along the HT line, making a 2-stage audio section unstable, (6SL7 & 6V6). I simply used a high-slope output valve & eliminated the pre-amp triode. Making your circuit would give me something I could run from the battery on my motorbike & it would be portable.
Man this build will keep u out of the high voltage..i built your loop ant and love it,, how abt simple tube transmitters cw/am i hope to hear u on in the us when the band opens up 73 kg6mn
Peter, Thanks for sharing this video which I found via VK6FH who provides a link and the schematic on his website. It's a great little regen and I plan to build one this summer. Did you notice the DX on 160m at minute 8:40 with VK3AMZ ending a CW QSO with G3FPQ ? Simply brilliant ! 73 Graham de G4VUX
Hello Peter, I also built this set out of pure curiosity. I did it slightly differently & built the chassis out of a base frame of wood with a deck & front panel that carries the speaker, variable capacitor, regeneration & volume control from some double sided PC board. I used the antenna coil from the Peebles AC-100PO set & a 1metre tuned loop antenna. I also incorporated the improvements noted in the cool186 web page. I used the LM386 amp with a small speaker. Works well. Peter VK5HPC.
Just found this video. Absolutely love it I'm itching to build one and was wondering what best tube to use and the bonus for me is the low voltage, amazing l..selectivity is impressive, quite nice loud audio I've got an old elac speaker from an old pye Westminster radio i would like to use, it would sound great. Do you have the circuit diagram?
Good show doctor! Like this video and your kit there. Would like to see a better shot of your handmade external antenna. Looks like something out of a frankenstein movie. Very Cool. 73
change the grid leak resistor (r1) to 2 megohm instead of the 100k .Change the grid leak for the audio to 1 meg (R3).Change the 22k plate reistor to 100k (R2).like your coil arrangement .The above values are more suited for a true regen .It will make a HUGE difference .
Hello Vk3ye, very good this radio, i have search in cool386 but did not find the schematic,please can you tell me where it is? Thank you so much Alexis old Xe1iak
I am wanting to use an LM386 IC to drive a speaker as you have done, in place of the emitter follower stage and phones, as above. I have a circuit for the complete 12AU7 circuit with LM386 that I printed out years ago, but am puzzled by a couple of component values, as follows:- (1) There is a resistor connected to pin 5 (output) that is labelled "1 " plus something that I cannot read. Is it supposed to be 1 ohm, 1K, 1M or something else? The other end of this resistor is connected to a 100pF (or is it 100nF?) capacitor which is connected to ground. (2) There is another, seemingly unlabelled capacitor connected from pin 7 (bypass pin) to ground. Is it also 100pF,100nF, or something else?
@@vk3ye Thanks for the reply. I should have explained that the emitter follower stage I mentioned is one I made using a BC549 transistor in place of an impedance matching transformer as used in the original Thames & Kosmos & cool386 versions, to drive Lo-Z HiFi stereo headphones. I was worried that excessive DC current through the phones could cook the windings, so I made up a prototype on a breadboard with a suitable resistor in place of the phones, and tried various values of base bias. resistors. I was able to ger it to operate OK with an emitter/headphone current of about 1mA (about 500uA in each phone, as L&R are connected in parallel). No need to reply to this.
Consegui montar um rádio desse ,pega am,oc,om,ssb....,até FM comercial e se tirar as bobinas e colocar um simples transformador junto comum auto falante vira um potente microfone ou pré-amplificador de áudio.
I haven't got a 12AU7, but I do have a 12AX7. Have you reverse-engineered yours to use this valve? Most of the available local stations are at the high-frequency end of the band where I am. If a 12AX7 is no good at all then my message will save some wasted effort on my part.
Just finished building a similar set using a 1Q5GT instead of a 12AU7. I also used an LM386 to drive a loud speaker. But the "magic" is in the front-end. The sensitivity and selectivity of these regenerative sets is just amazing!
Peter, thanks so much for your generosity in time to reply on your live stream!!!
This is a fantastic project !!!
Valves are large and easy to understand, using low voltages is even better!
Keep the simple but amazing projects coming please 🙏
Incredible! I never thought valves could run on such a low voltage, I know some transistor circuits that cant run on 12 volt. It sounds pretty good from what i could hear thought the camera.
Yeah Dave very pleased with how it turned out. Want to put it into a proper case and add some extra bands: ideally 0.5 - 2, 1.6 - 4, 3.5 - 7.5 & 7 - 20 MHz. SSB should be acceptable up to at least 40m.
Not all valves will apparently handle low HT, and anything that needs some power (eg an audio amp) is unsuitable. But that's what ICs can do well.
807 is amazingly good at low voltages
Built one myself many years ago for top-band and 80 with an ECC82.
Amazing. Wish I had the parts to try making it. No hand capacitance issues.
Someday someone make this a kit everyone can buy with directions ,I no a lot of people would buy it.
@hairymolly057 Glad you liked the radio. See the link in the description for the circuit.
@alexismex1 Yep it's there - checked today. In the cool386 link in the description above. There's 2 diagrams, the modified one about 2/3 down.
This was uploaded when there was music on AM
It appears that the radio uses a Hartley Oscillator as a detector.
I have used a electron-coupled Hartley oscillator as detector in my TRF experiments.
However, I should say that I have been using the big coke bottle Octal valves and 250V HT.
A solid-state output stage would certainly eliminate the problem of RF getting to the audio stage along the HT line, making a 2-stage audio section unstable, (6SL7 & 6V6).
I simply used a high-slope output valve & eliminated the pre-amp triode.
Making your circuit would give me something I could run from the battery on my motorbike & it would be portable.
Man this build will keep u out of the high voltage..i built your loop ant and love it,, how abt simple tube transmitters cw/am i hope to hear u on in the us when the band opens up 73 kg6mn
Great video, Peter. What was the hartley oscillator coil tap position?
@Jacob - link to circuit appears in above description (note updated link).
Peter, Thanks for sharing this video which I found via VK6FH who provides a link and the schematic on his website. It's a great little regen and I plan to build one this summer. Did you notice the DX on 160m at minute 8:40 with VK3AMZ ending a CW QSO with G3FPQ ? Simply brilliant ! 73 Graham de G4VUX
Hello Peter,
I also built this set out of pure curiosity. I did it slightly differently & built the chassis out of a base frame of wood with a deck & front panel that carries the speaker, variable capacitor, regeneration & volume control from some double sided PC board. I used the antenna coil from the Peebles AC-100PO set & a 1metre tuned loop antenna. I also incorporated the improvements noted in the cool186 web page. I used the LM386 amp with a small speaker. Works well.
Peter VK5HPC.
Just found this video. Absolutely love it I'm itching to build one and was wondering what best tube to use and the bonus for me is the low voltage, amazing l..selectivity is impressive, quite nice loud audio I've got an old elac speaker from an old pye Westminster radio i would like to use, it would sound great. Do you have the circuit diagram?
Thanks. Circuit & more details are linked in the video description.
Good show doctor! Like this video and your kit there. Would like to see a better shot of your handmade external antenna. Looks like something out of a frankenstein movie. Very Cool. 73
change the grid leak resistor (r1) to 2 megohm instead of the 100k .Change the grid leak for the audio to 1 meg (R3).Change the 22k plate reistor to 100k (R2).like your coil arrangement .The above values are more suited for a true regen .It will make a HUGE difference .
Who Needs Transistors, might modify the AR88 to run off AA cells and take it
portable.
Very good indeed
Hello Vk3ye,
very good this radio, i have search in cool386 but did not find the schematic,please can you tell me where it is? Thank you so much Alexis
old Xe1iak
Great video Peter. I was planning to have a go at this myself. Just wondering where the antenna coil should be tapped?
I am wanting to use an LM386 IC to drive a speaker as you have done, in place of the emitter follower stage and phones, as above. I have a circuit for the complete 12AU7 circuit with LM386 that I printed out years ago, but am puzzled by a couple of component values, as follows:-
(1) There is a resistor connected to pin 5 (output) that is labelled "1 " plus something that I cannot read. Is it supposed to be 1 ohm, 1K, 1M or something else? The other end of this resistor is connected to a 100pF (or is it 100nF?) capacitor which is connected to ground.
(2) There is another, seemingly unlabelled capacitor connected from pin 7 (bypass pin) to ground. Is it also 100pF,100nF, or something else?
1. 1 ohm resistor & 100nF capacitor.
2. 10uF.
Standard LM386 circuit.
@@vk3ye Thanks for the reply. I should have explained that the emitter follower stage I mentioned is one I made using a BC549 transistor in place of an impedance matching transformer as used in the original Thames & Kosmos & cool386 versions, to drive Lo-Z HiFi stereo headphones. I was worried that excessive DC current through the phones could cook the windings, so I made up a prototype on a breadboard with a suitable resistor in place of the phones, and tried various values of base bias. resistors. I was able to ger it to operate OK with an emitter/headphone current of about 1mA (about 500uA in each phone, as L&R are connected in parallel).
No need to reply to this.
hello VK3ye
Sorry to be blind,but where is that description to see above!!!!! in your video i did not see_ thanks
CoolDudeClem What do you think they used in the fields during ww2, and it's a quite powerful battery (it'd want to be for 25 dollars).
very clear. for fm 88 - 120mhz how many turns?
@alexismex1 See the link in the description above for the circuit
I cant get it to oscilate on 12 volts.the amplifier works though
Are there any other tubes you can use..thanks...this is a great video..
You can also use a 12U7.
Fun video! Amazing what a single tube ...er 'valve' can do! 73 Peanut
Friend excellent Regenerative Receiver please coil turns 7mhz ? please please 40m band coil?
Consegui montar um rádio desse ,pega am,oc,om,ssb....,até FM comercial e se tirar as bobinas e colocar um simples transformador junto comum auto falante vira um potente microfone ou pré-amplificador de áudio.
idea on coils yet? to get to SW 5mhz and up >>??? having tough time with that sideof this regen
Performance seems to drop off at higher frequencies. Try splitting the power supply so there's higher than 12 volts on the plates.
@@vk3ye sounds like a plan. ty..
I haven't got a 12AU7, but I do have a 12AX7.
Have you reverse-engineered yours to use this valve?
Most of the available local stations are at the high-frequency end of the band where I am.
If a 12AX7 is no good at all then my message will save some wasted effort on my part.
12ax7 has much higher gain, it will work but maybe more sensitive so may oscillate to much. Worth a try
amazing,what is your country?
Can you use an ECC82 in place of the 12AU7?
ECC82 is the same as the 12AU7
can I ask for a scheme?
See the links provided above
Great!! )))
Suiting, Russia
That is far from a country station.
peter might want to update that website as cool386.com dont exist now so it tells me.
colin K0lin