Search results

Search Forums New Posts
  1. Audioguru

    Analog guitar amp with digital meter

    Electric guitarists are deaf to high audio frequencies and do not hear the awful distorted fuzz that people with normal hearing hear. Old age also kills the ability to hear the awful fuzz. My new hearing aids make my hearing young again to hear then turn off the awful fuzz.
  2. Audioguru

    Charge time for lithium batteries

    Look at the numbers 18650. Each cell is 18mm in diameter and is 65mm long. The mAh is from 55mAh for a Chinese cheap fake one (many use the word "Fire" in their name) to about 3300mAh for a good name-brand one.
  3. Audioguru

    Analog guitar amp with digital meter

    Tubes in this day and age?? Many bands replace the worn out antique tubes after each show. Then a timer was not needed for them to produce the muffled and distorted old sounds.
  4. Audioguru

    Is it wrong to leave a transformer plugged in ??

    Most safe electrical products I have seen have a manufacturer's name on the spec's label. This power supply is hiding the name like the defective compact fluorescent light bulbs that were given out then recalled because they dripped flaming plastic. Seeing the missing manufacturer's name and...
  5. Audioguru

    Audio limiter to quiet loud radio commercials

    Most audio sinewave generators and audio automatic level controllers use a Jfet to set the level. The Jfet on-resistance is the same with either polarity of the input signal so that the distortion is very low. I think that your rectifier is too simple to be a fullwave active rectifier. The...
  6. Audioguru

    Audio limiter to quiet loud radio commercials

    I sketched an audio attenuator using a Jfet:
  7. Audioguru

    Audio limiter to quiet loud radio commercials

    Junkbox parts?? You must look at the datasheet of a Jfet to select one that works with the supply voltage you are using. A 2N3819 Jfet might kill your supply when it is turned on and needs a fairly high gate voltage to turn off. A 2N5484 draws a low current when turned on and needs a low gate...
  8. Audioguru

    Audio limiter to quiet loud radio commercials

    Three Jfets can modulate a Morse Code signal on and completely off, but one Jfet can pass audio or block it, or a resistor can pass audio then a Jfet to ground can almost completely turn it off.
  9. Audioguru

    Audio limiter to quiet loud radio commercials

    You do not need 3 Jfets, you need only one Jfet plus a resistor to make an audio switch. Also, most Jfets activate from only a few volts, not 18V. This voltage can be the positive supply voltage, not an additional negative voltage. What will activate the switch? Rectified program audio has many...
  10. Audioguru

    Audio limiter to quiet loud radio commercials

    Years ago, an incandescent low power light bulb to ground was used as a level control in an audio oscillator. But it was very slow and when a loud signal was the input then the levels bounced until it became steadily reduced.
  11. Audioguru

    Audio limiter to quiet loud radio commercials

    Your diodes would cause severe distortion to loud speech and loud music in addition to loud commercials. Usually a compressor rectifies the signal and feeds the DC to the gate of a Jfet that cuts the peak levels of the audio. The original commercial compressor reduces levels of the peaks which...
  12. Audioguru

    What should I do with unused outputs?

    The absolute maximum allowed output current of your 74HC163 is 25mA. But it has enough power to conduct 68mA into a shorted output which will destroy it. If you connect an output to ground (which is a logic low) but an input causes its output to try to go to a logic high then it will be destroyed.
  13. Audioguru

    What should I do with unused outputs?

    I don't have many unused outputs but instead I have a lot of amplifier power that is rarely used. I hate audio distortion and never play acid rock so I keep my amplifiers away from full power clipping. It would be good if I could save then later reuse the unused extra power. Remember when AA...
  14. Audioguru

    Cube Adaption to Amplifier

    The Banggood amplifier has stereo mic inputs (for people with two heads;)) with its volume control and has a stereo line input with its own volume control. I think the line inputs will not be used since the guitar is probably acoustic, not electric. I do not think the tiny low power speakers...
  15. Audioguru

    bridge 2 channels into one

    I just replied to another thread that mentioned the Banggood Chinese "digital 60W" amplifier. It is not digital and does not produce 60W. Its IC is class-AB and each channel is already bridged.
  16. Audioguru

    Cube Adaption to Amplifier

    The 22W is the electricity input power that mostly creates heat. The speakers are tiny and low power, two are 4W maximum and two are only 2W maximum. The Banggood Chinese amplifier uses the TDA8946 IC that is not digital and does not produce 60W. Its output is shown on its datasheet to begin...
  17. Audioguru

    What should I do with unused outputs?

    If you ground an output then it is shorted to ground. Then there will be damage when it tries to go high. The outputs use powerful Mosfets without any resistors to limit the current. Leave the unused output with nothing connected to it and it will be fine.
  18. Audioguru

    Modifying 4.5 V (alkaline) lamp to run brighter with 3.6 V (NiMH)

    I mentioned a voltage higher than 4.5V because a Ni-MH cell is 1.4V or 1.5V when fully charged. Its voltage drops to 1.2V after discharging for a while. Then if you boost the fully charged 4.5V to 5.6V the circuit might smoke and burn. You need a regulated 4.5V from the booster that still...
  19. Audioguru

    Blinking LED’s

    That wrong circuit with the TIP31 power transistor was an Instructable made by a kid who was only 10 years old and who knew nothing about electronics.
  20. Audioguru

    Converting an existing amplifier into a subwoofer amp

    A single capacitor makes a 1st-order lowpass filter like the simple tone controls on an amplifier. It is useless for a subwoofer. You need an active 2nd-order or 3rd-order lowpass filter plus matching active highpass filters for the other speaker amplifiers.
Top