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  1. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    If the metal case of a pot picks up electrical hum then it will feed the hum into the circuit. But if the metal case is connected to the circuit ground then there will be no hum produced by the pot. Since the output impedance of the preamp is much higher than all other preamps then the output...
  2. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    You have preamps designed for piezo pickups. They can easily drive the 50k or higher input of an audio amplifier. The input of many guitar amplifiers is 1M or more to be fed from a magnetic pickup. With a volume control and tone control on the guitar then the total resistance fed by the pickup...
  3. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    Most preamps made with an opamp have an output resistance of 100 ohms or less so 1k mixing resistors are fine. Since your preamps have a higher output resistance then use a 10k linear blending pot instead of the 1k resistors as I showed. Then you can use a 50k log volume control. Amplifiers...
  4. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    Experts say that a magnetic guitar pickup should feed a preamp that has an input impedance of 1M or more, to make a peak at about 4kHz. When it feeds a lower resistance then the peak disappears and the high audio frequencies are muffled. That is why vacuum tube guitar amplifiers had an input...
  5. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    Alec gave me a couple of ideas:
  6. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    No, you cannot connect the outputs of the preamps together because then each one is short circuited. Instead you must use a mixer to mix or blend them together. A series resistor from each preamp output can be connected together to make a simple mixer but then you cannot adjust their amounts of...
  7. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    A volume control is a logarithmic pot. A linear pot is used for adjusting a voltage or as a balance control. The value of a volume control depends on the input impedance of the mixer or amplifier it feeds. How can you "short circuit" outputs of preamps together? Instead you should mix or blend...
  8. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    I disagree. The pot is connected backwards so when it is turned clockwise the volume goes down and when it is turned counter-clockwise the volume gores up. But a volume control should be logarithmic like our hearing, not linear. Since the preamp feeds your mixer then why doesn't your mixer have...
  9. Audioguru

    Blocking Oscillator

    Your first circuit is similar to the circuit is a cheap solar garden light. The two transistors form a PUT (look it up) and create very low duration pulses that will not work well in a transformer.
  10. Audioguru

    Receiving a radio signal...

    I agree that the 10.7MHz from the mixer will never be zero. It will have either signal or noise. Maybe its muting circuit detects the amplitude fluctuations of the noise?
  11. Audioguru

    Building a device from a schematic (Yet another work in progress)

    This thread is very old so a lot of things do not appear today.
  12. Audioguru

    buttons for bluetooth receiver

    When the Bluetooth module uses pushbutton switches to control the volume then a pot cannot be used instead. Why did you connect the pot (and a battery?) to two LEDs? If the volume changes each time a volume pushbutton is pressed then an LM3914 LED controller can be wired so that a pot is used...
  13. Audioguru

    2-channel passive mixer-independent volume control for each pickup

    When the pot is wired correctly as a signal voltage divider with its center pin feeding the preamp, then the pickup is always connected to the 500k resistance of the pot. A magnetic geetar pickup will work this way but a 3M pot resistance works better. A piezo pickup needs 10M. But your idea of...
  14. Audioguru

    Will this synthesizer work?

    That website (in India?) does not work right now. If the diodes allow the 555 ICs to work then they will almost play the same frequency. Why use three oscillators when one will work much better? Use an audio mixer circuit to mix three oscillators together. Since they play almost the same...
  15. Audioguru

    Will this synthesizer work?

    Here are the important coupling capacitors and negative feedback for the mixer.
  16. Audioguru

    Will this synthesizer work?

    I do not know what you are doing because you do not know what you are doing.
  17. Audioguru

    Will this synthesizer work?

    Buzz, buzz, beep,beep is not a synthesizer.
  18. Audioguru

    Will this synthesizer work?

    Years ago I converted a high frequency squarewave to an oversampled sinewave. Instead of the 16 stage shift register shown here, I used a simple 5 stage CD4018 counter with 5 resistors creating 10 steps. One of the counter outputs is the squarewave and the counter is fed from a 10 x the...
  19. Audioguru

    Will this synthesizer work?

    A Cmos 555 can produce a perfect squarewave with the simple circuit using the output pin.
  20. Audioguru

    Will this synthesizer work?

    Please look on the datasheet of a 555 how to make an oscillator.The rectangular output of the 555 sounds awful like a buzzer. Your filters are so simple that they do nothing at low frequencies and reduce the levels at high frequencies before the waveform is near a sinewave. You are using...
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