Tube Amp

Started by Dave.H in sci.electronics.basics15 years ago 13 replies

Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to go with a regenerative radio. Does not have to be the best, but needs to...

Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to go with a regenerative radio. Does not have to be the best, but needs to drive at least 250 mW speaker, preferably 1 watt or more. Thanks, Dave Australia


Building a class A audio amplifier - no audio out

Started by Anonymous in sci.electronics.basics14 years ago 68 replies

I tried to build this Class A amplifier circuit as a learning experience: http://www.techlib.com/electronics/audioamps.html#class-a with the...

I tried to build this Class A amplifier circuit as a learning experience: http://www.techlib.com/electronics/audioamps.html#class-a with the following modifications: 1. I have no MPSW45, so I built a Darlington out of a 2N2222 and TIP31A. 2. 150k resistors: I only had two 100k resistors in my collection. But as long as they're identical, should work...??? 3. speaker: I had only a 10W...


microphone impedance vs. speaker impedance

Started by Bruno in sci.electronics.basics8 years ago 21 replies

Hi, If I measure the DC resistance of a hi-fi speaker with an impedance of 8 ohms, it comes out at approx. 8 ohms. But when I measure the DC...

Hi, If I measure the DC resistance of a hi-fi speaker with an impedance of 8 ohms, it comes out at approx. 8 ohms. But when I measure the DC resistance of a dynamic microphone with a stated impedance of 50k ohms, it comes out as only 1500 ohms. Another dynamic mic with a stated impedance of 400 ohms reads only 1.1 ohms DC resistance. Why do mics DC resistance seem to measure different...


Diagnosing speakers

Started by Andy in sci.electronics.basics2 years ago 16 replies

I have a 6 speaker home theater system. However the middle 2 speakers have no sound. I checked the voltages. 0 volts when a movie is...

I have a 6 speaker home theater system. However the middle 2 speakers have no sound. I checked the voltages. 0 volts when a movie is playing versus .22 Vdc when movie is not playing. Does that help at all? Thanks, Andy


Using mobile phone as an internet radio

Started by jim stone in sci.electronics.basics10 years ago 136 replies

Not being able to find a small internet radio to buy we liked, we got mobile phone with which we link with wi-fi to a modem router, and use it...

Not being able to find a small internet radio to buy we liked, we got mobile phone with which we link with wi-fi to a modem router, and use it as an internet radio. Keeping the phoned plugged into its charger all the time, we are using it to play *all-day* background classical music through an amplifier and speakers. Since the phone has no 'moving parts' unlike a computer, we are wonde...


Subwoofer help

Started by AK in sci.electronics.basics2 years ago 5 replies

I would like to add a sub-woofer to my home theater system. My system calls for speakers in the 6 -> 16 ohm range. When I searched Ebay, I...

I would like to add a sub-woofer to my home theater system. My system calls for speakers in the 6 -> 16 ohm range. When I searched Ebay, I found some speakers, but found out that they need a crossover. My system has an output for a subwoofer. Could someone show me a link to something for sale or else the specs I need to look for? Thanks, Andy


anti-music "remote control"

Started by Eli the Bearded in sci.electronics.basics9 months ago 3 replies

https://www.vice.com/en/article/jg8wnb/square-dancing-noise-china Residents who are fed up with the noise from China's ubiquitous ...

https://www.vice.com/en/article/jg8wnb/square-dancing-noise-china Residents who are fed up with the noise from China's ubiquitous "dancing grannies" are resorting to a special device that could mess with the speakers that blast out loud music. They use an infrared remote control dubbed "anti-square dancing magical device" to silence the noisy dancing troupes that have ...