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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Why are JJ Electronic R.F. preamp tubes preferred over A.F. tubes in guitar amps?
JJ Electronic has both R.F. (radio-frequency) and A.F. (audio frequency) versions of some of their tubes.
Yet in far the most tubeshops for guitar amps they only sell the R.F. versions (ECC83 S - ...
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Any tips on designing an audio preamplifier for low frequencies?
I'm currently trying to design an audio preamp with the purpose of amplifying very faint audio signals (possibly in the microvolt range) from 20-200Hz. I've tried both transistors and op amps for ...
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Help with resistor in gain and filter op-amps circuit
I'm designing a piezo preamp with high-pass filter using two preamps. The first one amplifies the signal, while the second one filters it (and some little extra gain). See schematic:
simulate this ...
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Question regarding simple preamp+audio amplifier
simulate this circuit – Schematic created using CircuitLab
simulate this circuit
Hello,as you can see,I constructed a circuit which consists of an amplifier(first scheme) and a preamplifier(...
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Preamplifier before latch stage in comparator circuit
Adding preamplifier based on simple inverter before latch stage can improve performance of comparator by decreasing offset voltage. Can anybody explain me how it works?
Best Regards
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transistor mic preamp
Hi I built this mic preamp circuit for use with an electret mic.
The mic I have is this PUI AOM4544 electret mic
I have plugged this mic preamp circuit to my soundcard line in. But I think the gain ...
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How does one calculate the input impedance of a tube based preamp?
I'm finding tons of information and equations on calculating this for solid state devices, but nothing for good old fashion particle accelerator based amplifiers :P
Currently I'm revamping the K270 ...
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Need a voltage follower buffer for a tube, how do I calculate and select a mosfet?
I'm finishing up a design here: https://123d.circuits.io/circuits/852190-jan-6418-vaccum-tube-valve-preamp which is a preamp for an instrument.
First, let me know if anything stupid pops out at you ...
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jfet preamp output attenuated and clipped on bottom rail when connected to codec
I am currently working on an embedded audio processing system for electric guitar. I have constructed two JFET preamps (left and right channels) based on the j201 transistor using the common source ...
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Why Doesn't This Op Amp Preamp Circuit Amplify?
I have the following circuit as part of a class D amplifier:
simulate this circuit – Schematic created using CircuitLab
I couldn't get the amplitude of Vsig to display, it is ~.447Vp, to ...
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cirrus/wolfson wm8731 - Connecting Analog Input to Codec
I am currently working on an embedded audio processor project based on the stm32f4discovery board and the wm8731 codec from cirrus/wolfson.
I was wondering if anyone here is familiar with the codec ...
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Identify this 2xNPN AC-coupled preamplifier circuit
My workmate has this nifty little EMI-detecting wand he built back in 2000. It senses EMI fields using an approx. 200 turn air-core coil, and converts them to audio signal. He uses it to detect e.g. ...
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Micro audio preamp with low consumption [SOLVED] [closed]
The audio output for all of my devices/computers is too small to push my speakers to the maximum.
I want to build a very small audio preamplifier to hook between the computer and speaker to boost the ...
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Source of a NP 47µF 60+V capacitor for audio? [closed]
I am building a preamp which calls for a 47µF 60+V capacitor. It needs to be non-polar and being audio low ESR. (Yes, this is a 1NA217 based circuit.) The circuit requires NP caps if phantom power is ...
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Try to make a preamp guitar
Hi i found this circuit in the net beacuse i want to make my preamp guitar..
I built it on my breadboard but when attach the battery, guitar doesn't make sound even if the amplificator is on... Have ...
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LM3886 full amp reduces hi freqs
I've bought this kit and successfully assembled it.
I use 23.4-0.23.4 V power source and two ELZET 10000uF caps.
So, after I connected my speakers (by the way it is Amphithon (Амфитон) 25АС-027 4 Ohm,...
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How is this preamp design?
I'm trying to design a preamp for this electret mic.
I kind of pieced this schematic up from something I have found on the web.
Does that look ok? I'm going to sample the output with an ADC (...
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Microphone Pre-Amplifier explanation
Here is the circuit of pre-amplifier which makes the weakest signal compatible for power amplifier to take for further amplification.
I literally can't understand this circuit's working. Which class ...
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How does a pre-amplifier work and why is it needed? [duplicate]
I am making an amplifier and came across the fact that, if I want to operate a microphone then I will need a pre-amp.
What is the difference between power amplifiers and pre-amplifiers? Do both of ...
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Electret Microphone Preamp Circuit
The following electret microphone preamp circuit seems to work pretty well. My electret model is a little off because on the bread board R6 needs to be ~33k to get the output at 1/2 supply.
Just a ...
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Bandpass audio filter in combination with PGA2311 analog ouput pins
I am working on modular preamp and I have Digital&Analog Power Supply, motherboard with CPU and Volume Control daugtherboard. On Volume Control Daughterboard there is an PGA2311 Volume Controller ...
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Faulty operational amplifier of electret mic preamplifier
I am debbuging a preamplifier for two electret mics. I use opa345 which is a dual low power op amp and i use the same topology as in this link for each channel: http://freecircuitdiagram.com/2008/09/...
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Electret microphone: selecting a bias resistor
I have inherited a circuit from a colleague using a MAX4063 pre-amplifier and an electret microphone. It's almost identical to figure 4 from the preamp datasheet:
But where that circuit has 2× 1 kΩ ...
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Line level voltage to drive LED display
EDIT: Please read the whole post before automatically down voting. I KNOW the diagram is crap. That is what I am asking about. It isn't my diagram.
Original post:
I Web searched a bit and ...
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Circuit analysis of mono audio preamp (K1803 Velleman)
For a school project I have a question about the first part of the circuit below (amplifies at 20*log(220k/2.2k)=40dB). I know that U2A is the amplifying part of the circuit. The problem is U1A and ...
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damaged capacitor and/or power amp
I have a Mackie MR8 MK2 powered studio monitor that recently started making a horrendously loud humming and clicking noise (I mean LOUD, as in cover your ears). Being just out of warranty, I decided ...
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correct wiring of a preamplifier and a lock-in amplifier
I've got a question regarding the correct wiring.
I'm operating a vibrating sample magnetometer. It uses two coils to detect the magnetisation via induction. The two signals are amplified and mixed ...
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The "10x rule" for impedance bridging
Quoting the Wikipedia impedance bridging article . . .
A connection is commonly said to be bridged if the load impedance is
at least ten times the source impedance.
Why the magical numer 10?
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Mic preamp: Inverting or non-inverting op-amp configuration?
What are the relative merits of using inverting/non-inverting op-amp configurations for a microphone preamp? While searching for microphone preamp schematics based on op-amps, I have found both ...
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Capacitor values for non-Inverting op-amp circuit
I found the following schematic here and built it to test it . . .
I think all the capacitors are there to just block DC, but how important are the capacitance values and how does one determine the ...
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Purpose of these two transistors
Hi does anybody know what's the purpose of the Q1 and Q2 transistors,
sounds to me like they are constant current sources. Am I wrong?
Could somebody explain me the purpose of those Q1 and Q2 ...
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What makes a mic preamp good or bad?
What are some of the factors that makes a microphone preamp good or bad?
noise, cancelling reverb and other factors.
I'm trying to build a electrec Mic that will handle voice recognition, from a ...
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Replacing a LM741 op amp with higher quality op amp?
I am a complete novice with electronics...but i'm looking to build a replica of a discontinued TC Electronic Integrated Preamp. Its a basic line booster with Volume, Bass and Treble but sounds great ...
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How to use a DKO48 telephone microphone?
I have an old telephone made in the sixties (FF-OB/ZB or FF53). Now, I was planning to make an external speaker for that telephone, but I failed miserably, so I've put that aside.
Now, the handset ...
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What is ALC on a preamp?
I have a preamp rescued from an old stereo: BA3308
It has a pin "ALC" and the data sheet keeps going on about how splendid this ALC is and how it has a built-in ALC diode and such.
Nowhere does it ...
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