Questions tagged [preamp]
A preamp takes in very weak DC voltages or audio or RF signals and amplifies them enough to be used by a more conventional amplifier. Input may be in microvolts and output maybe 1 volt RMS or peak. They are often specific to amplify DC, LF/audio, RF or microwave bands. No preamp can cover DC to microwave bands and have good parameters at both DC and RF without software offset and gain correction.
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What is the maximum dBu I can send into a microphone input in this schematic?
The schematic below is from the Icom 9700 radio service manual (page 80). I would like to feed this input from a mixer board's ALT-3/4 outputs, and I want to avoid blowing the TS462 microphone preamp ...
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Can an audio isolation transformer between a preamplifier and an amplifier cause the amplifier's fuse to blow? [closed]
I'm building a microphone preamplifier. I was having problems with hum (intermittent ground hum when touching the case) and decided to try adding an audio isolation transformer (600 ohm : 600 ohm) ...
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How can the microphone senstivity be improved? It works for only a few centimeters
I am using an electret microphone with the preamplifier circuit attached below. The problem is that the microphone works only when I speak very closely to the microphone. If I speak from a distance, ...
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Excessive DC offset in high-speed opamp amplifier circuit
Background
A while ago I got my dad's old Musical Fidelity A1 MKI integrated amplifier from the early 80s (I believe). I found a blog that featured a lot of interesting information about this ...
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Trying to record from DIY op-amp results in seldom pops and clicks
I have a 741-based audio amplifier PCB here from the 70s:
When I tried to test it, I powered it with a 24V battery (I tried 12V as well with no difference,) then I shorted pins 15-19, connected the ...
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Voltage Buffer Vs Impedance matching
I am designing an Amplifier circuit for the microphone. For this, I am using a buffer in between two stages for isolation and I am confused between 2 circuits. I know, in voltage buffer circuits, the ...
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Output-Z (electret) higher than Input-Z (preamp)
What happens if an electret microphone capsule (JFET in catridge) is connected to a preamp with considerably lower input impedance than the capsule's output impedance itself?
ECM output Z: 2.2K
Preamp ...
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Understanding this MM/MC discrete phono stage
I am challenging myself at understanding my integrated amp's MM/MC phono stage; The amp is a Rega Elicit mk. I. It is a somewhat complex design and as a hobbyist I'm out of my league. The circuit ...
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Something about the impedances of charge amplifiers
it is my understanding that due to the effect of virtual grounding, the input impedance of a charge amplifier is basically zero. If that's the case, then is there any reason to even worry about the ...
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Extremely Noisy Preamp Circuit on Breadboard (EDIT: Oscillation?)
I built a simple circuit (included below) on a breadboard and have been having some trouble with noise. Generally speaking, I get what seems like random noise averaging at about 1.5Vpp. Otherwise, I'm ...
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Why am I getting this distortion in this circuit?
Can someone explain to me why I am getting this distortion for the following circuit? Input is a pure square wave. It happens at any input frequency or voltage. I was thinking the output would be a ...
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No Output for Preamp circuit in TINA
Is this a spice problem or a design(me) problem? The rails are producing the expected 9 and -9 volts, but nothing is coming through on the output. I haven't ever done op amps without a bias voltage ...
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Suggestions for Improving this Pre-amp Circuit
I made this preamp circuit for a dynamic mic and am mostly happy with it, but I'd love to get suggestions on how to make it a little better. I'd like it to have as little coloration as possible, and ...
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Why Am I Not Getting my Expected Output in this basic Op-Amp Circuit?
I thought that A = 1 + Rf/Ri for an op-amp non-inverting amplifier? With a 1mV input, I'm getting output voltages in the uVs...
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Microphone pre-amplifier op-Amp outputs larger voltage when Mic RL is larger
I am following TI's pdf Non-inverting microphone pre-amplifier circuit with AOM-4544P-2-R microphone. I probe the circuit on the Vout after the op-amp, (not on the mic directly). I am playing around ...
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