Tube Amp

Started by Dave.H in sci.electronics.basics12 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.basics11 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...


Noisy Phone (speaker?)

Started by W. eWatson in sci.electronics.basics8 years ago 6 replies

We have a Panasonic cordless set of phones. In the last month, we've noted that occasionally the ringer (speaker, I suppose) sounds very...

We have a Panasonic cordless set of phones. In the last month, we've noted that occasionally the ringer (speaker, I suppose) sounds very rough. My wife finally put it on another circuit for nearly a month. No problems. I think it's another device on the circuit that causes the problem. Here's what's on that circuit. The kitchen circuit containing the phone plug includes: 1. Kitchen...


AC current relay

Started by Anonymous in sci.electronics.basics8 years ago 15 replies

I want to switch on some receptacles when another one is drawing current. I want my remote controlled TV to turn on the equipment ancillary...

I want to switch on some receptacles when another one is drawing current. I want my remote controlled TV to turn on the equipment ancillary to the television - converter box, antenna rotor, speaker amp. Ideally something that can sense down to 1 amp or so then energize the other outlets, and uses minimal current itself. These things used to be fairly common to switch off the other comp...


Tide table audiograph

Started by Stumpy in sci.electronics.basics8 years ago 14 replies

I was looking at a tide table to find minus tides during the daytime to go poke at creatures and I thought that the fairly regular wavelength...

I was looking at a tide table to find minus tides during the daytime to go poke at creatures and I thought that the fairly regular wavelength would make some very boring music. If you sped up the frequency from days to kHz and had feet represent either volts delivered to a speaker, or actual sound waves you would hear something. Probably a very regular tone that varied more in volume t...


Electrolytic capacitors & playing with 556 chip

Started by Adam Funk in sci.electronics.basics8 years ago 14 replies

I wired up a 556 (two 555 timers on one chip) as follows: Timer A: astable circuit with equal mark & space width, R = 267 ?, C = 1000 µF...

I wired up a 556 (two 555 timers on one chip) as follows: Timer A: astable circuit with equal mark & space width, R = 267 ?, C = 1000 µF (electrolytic with 25 V rating), output: 320 ? in series with an LED, also tied to the reset pin on Timer B Timer B: same astable timing arrangement, R = 100 k ?, C = 10 nF (non-electrolytic), output: piezo speaker in series with a resistor


Designing The Perfect Coil?

Started by Ron Hubbard in sci.electronics.basics8 years ago 113 replies

I want to do an experiment in brainwave entrainment by making a 7 Hz sine wave oscillator out of an XR2206 frequency generator IC and a LM386...

I want to do an experiment in brainwave entrainment by making a 7 Hz sine wave oscillator out of an XR2206 frequency generator IC and a LM386 amplifier feeding a six inch diameter coil-- which should probably fit around my fat head. ;-) The LM386 has an 8 ohm output, so it shouldn't be hard to find a speaker, if I wanted to use one; but I don't know how to make a good 8 ohm coil to radia...


Reduce sensitivity of 100K ohm volume potentiometer?

Started by Anonymous in sci.electronics.basics7 years ago 6 replies

I have an audio DSP filter for my amateur radio equipment. It uses an LM380= op-amp in the final AF amp stage, using a 100K ohm pot as the...

I have an audio DSP filter for my amateur radio equipment. It uses an LM380= op-amp in the final AF amp stage, using a 100K ohm pot as the volume contr= ol. When using a speaker the volume control is fine, but when using headpho= nes, the sensitivity from quiet to really loud is only a small tweak of the= volume know. Anything I can do to reduce this sensitivity for my headphone output? ...


Speaker resistance and sound energy

Started by M. Hamed in sci.electronics.basics7 years ago 15 replies

I was reading the ARRL handbook (2010) and on page 4.7 there was this sentence: "it can be said that any device that dissipates power has a...

I was reading the ARRL handbook (2010) and on page 4.7 there was this sentence: "it can be said that any device that dissipates power has a definitive value of resistance" This made me think. I always see speakers modeled 8 Ohms. And this is probably their DC resistance value. But shouldn't the conversion to sound be accounted for somehow since it's a sink on energy delivered? I thought ...


Any speaker experts here?

Started by Anonymous in sci.electronics.basics6 years ago 33 replies

This speaker question kinda goes with my previous question(s) about tubes. I have been looking at tube stuff on the web and some of it really...

This speaker question kinda goes with my previous question(s) about tubes. I have been looking at tube stuff on the web and some of it really appeals to me. I'm a machinist and have a shop so making knobs and the like is easy for me to do. And some of the tube sets with exposed tubes and transformers sure are pretty. So I got to thinking about speakers. I would like to have metal enclosures (...


low-power audio amp basics

Started by Anonymous in sci.electronics.basics6 years ago 14 replies

For some low-power audio amps, usually less than 2 Watts, I see the amplifier powered by +V...

For some low-power audio amps, usually less than 2 Watts, I see the amplifier powered by +V and ground: http://www.redcircuits.com/Page33.htm For other, usually higher-powered amplifiers, I see a +/- power supply required. http://www.redcircuits.com/Page164.htm Do the amplifiers without a +/- supply continuously provide a voltage at 1/2 V during the silent parts, to allow the speaker room ...


usb headphone speaker has 4 pads and ? 3 wires ?

Started by robb in sci.electronics.basics5 years ago

trying to replace left headphone speaker in a set of USB headphones with mic Headphone very like...

trying to replace left headphone speaker in a set of USB headphones with mic Headphone very like this http://www.frys.com/product/4452636 Speaker like this http://www.digikey.com/product-detail/en/AS02808MR-2-R/668-1397-ND/4147321 The circuit board part with solder pads separated from the speaker from a fall to floor and the wires are so fine from speaker part i can not tell where t...


microphone impedance vs. speaker impedance

Started by Bruno in sci.electronics.basics5 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...


Looking for folks who know about Speaker Identification

Started by Ramon F Herrera in sci.electronics.basics5 years ago 12 replies

*Important Note:* If you rather not be involved in activism, anything remotely political etc. PLEASE go to the next post. Shalom. Vaya con...

*Important Note:* If you rather not be involved in activism, anything remotely political etc. PLEASE go to the next post. Shalom. Vaya con Dios. ================================================================== We started a project where The Community (Usenet, Social Media, We The People, whatever that means) will participate by looking for audio/video clips of Mr. Bill O'Reilly,...


High-pitched sound by you're house? High-pitched machine....

Started by Anonymous in sci.electronics.basics5 years ago 1 reply

The elderly in particular use a cat-deterrent in their garden. It is a small apparatus with a speaker attached to it. It produces a high-pitched...

The elderly in particular use a cat-deterrent in their garden. It is a small apparatus with a speaker attached to it. It produces a high-pitched bleep of more than a 100 decibel. The sound is mostly only audible for children, youngsters and people with ears that are still good. Many cat-deterrents use the same noise as the Mosquito. The sound causes pain in the ears, headache, and ringing in ...


Before it's put on a slow boat from China

Started by amdx in sci.electronics.basics5 years ago 13 replies

I need a 2.7uf 63V non-polarized capacitor for a speaker crossover. It is a radial lead 10mm x 22mm cap. Ebay has them from China. (slow...

I need a 2.7uf 63V non-polarized capacitor for a speaker crossover. It is a radial lead 10mm x 22mm cap. Ebay has them from China. (slow boat) I've checked Digi-Key, Mouser, Allied, and Newark. I've also checked several speaker part sellers. I have found an axial lead cap, for $0.50 plus $6.95 shipping. But I'd prefer a radial lead. Have any other sources? Refoamed a set of Pione...


Adhesive to hold Speaker crossover components

Started by amdx in sci.electronics.basics5 years ago 16 replies

I'm replacing a couple of capacitors in speaker crossover. The parts have a glue that holds them tight to the PCB, the glue is still a little...

I'm replacing a couple of capacitors in speaker crossover. The parts have a glue that holds them tight to the PCB, the glue is still a little bit rubbery after 33 years. (Pioneer HPM-700) What can I use that will do the same job, without solvent damage to the electronic parts? Mikek


Interface between Sat phone and PC SW?

Started by Anonymous in sci.electronics.basics4 years ago 3 replies

Is there a way of connecting a Windows PC to a satellite phone so that the = following can be done from software running on the PC: 1....

Is there a way of connecting a Windows PC to a satellite phone so that the = following can be done from software running on the PC: 1. Remotely control the satellite phone from software on the PC (i.e. answe= r call, hang up call, adjust speaker volume, adjust mic sensitivity etc) 2. Receive speaker audio stream as a digital 16-bit signed PCM mono audio s= tream. 3. Send 16-bit signed PCM ...


How to tell speaker + from -?

Started by Anonymous in sci.electronics.basics1 year ago 12 replies

In my shop I have a a Pioneer SX-434 radio/amp for my listening pleasure. The speakers are mounted high up, screwed to the wall, and are not...

In my shop I have a a Pioneer SX-434 radio/amp for my listening pleasure. The speakers are mounted high up, screwed to the wall, and are not easy to get at. I had to disconnect the speaker wires temporarily from the stereo and stupidly didn't mark the wires for positive and negative. Is there a way to tell which wires are which that doesn't involve ladders and me unscrewing the speakers from...


Speaker efficiency?

Started by Anonymous in sci.electronics.basics1 year ago 12 replies

Since I will be playing a low wattage tube amp through speakers it seems that high efficiency speakers are in order. How can I tell...

Since I will be playing a low wattage tube amp through speakers it seems that high efficiency speakers are in order. How can I tell the efficiency of a speaker from looking at the specs? Thanks, Eric