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votes
1answer
40 views

Op Amp over the rail output voltage

I'm designing a RIAA pre amplifier based on the 2 op amps from a NE5532 package. It seems that something is wrong, cuz the output of the 2nd stage is giving a 400V output which is way over the rail ...
0
votes
2answers
47 views

Amplifier Audio Ground to Signal Ground

I am using a VS1053 (on a SparkFun Music Maker shield) to provide audio for my project. I am taking a line out signal and inputting it into an op amp for signal processing, ultimately being input to ...
6
votes
6answers
2k views

Why does this potentiometer in an op-amp feedback path cause noise when adjusted?

I have placed a dual-gang 100k potentiometer in the feedback path of two op-amps that work as a Sallen-Key filters. This controls gain but also the Q factor of the filter (somewhat demonstrated on ...
0
votes
1answer
53 views

What will be the effect of changing the order of the filters on the sound coming from each speaker in my audio system?

What will be the effect of changing the order of the cross over filters on the sound coming from each speaker in my audio system?
0
votes
0answers
36 views

how would a non inverting op amp tone boost work?

I'm modifying an audio circuit to add more tone controls, and found a method I want to try. It involves separating the wanted frequencies into a boost circuit and the less wanted frequencies around ...
0
votes
0answers
44 views

Line level audio output from headphones level output

I am new to analog audio interface design. I am trying to get a line level output from a amplified headphones level output. I want both of the output to work at the same time in order for the user to ...
0
votes
0answers
36 views

Remove Echo in an Op Amp

I have been working with a distortion circuit that has an op amp amplifying the volume before sending it through the diodes. The op amp is configured as a non-inverting op amp with a feedback resistor ...
0
votes
2answers
307 views

LM358n versus LM386 for audio amp

Here's the pinout diagram for an LM358 Here's the pinout diagram for the LM386: Here's a very basic circuit showing an audio amplifier created using an LM386: If I built the equivalent circuit ...
0
votes
0answers
43 views

Negatively offset signal on op-amp

I am simulating the use of a tl074 quad op-amp and i have configured one of the op-amps as a non-inverting op-amp, where R1=1 Meg and R2=4 Meg and the supply voltage is 9V. Every time i put a signal ...
0
votes
1answer
50 views

Volume Control for Mixer Circuit using DAC Refence

I am mixing two stereo audio signals together and would like to control the output volume using the (0-3.3v) DAC on my microcontroller. I'm wondering if there is a simple modification I can do to this ...
1
vote
1answer
28 views

Handling Phase Shift with ANC

I've been working on a circuit to do active noise cancellation, but I'm worried about controlling the phase. Here are my assumptions, and I'd love some help understanding 1)what of my assumptions are ...
5
votes
3answers
1k views

OP Amp not amplifying audio signal

Hi, part of my project requires me to amplify an audio signal coming from an electret condenser microphone which outputs an average of 10mVpp to approximately 2.5Vpp. I Used two cascaded non-inverting ...
0
votes
1answer
61 views

OPA690 Stability

I'm having difficulties keeping this opamp from oscillating and heating up.The schematic is a slightly modified Mini3(mini cube )amp schematic with active ground. A 1nF cap across the 330 ohm ...
2
votes
1answer
223 views

Generating a constant-amplitude triangle wave from a square wave

I have designed a circuit that can generate sawtooth and arbitrary duty cycle pulse waves controlled by some variable DC current source \$I_0\$, giving a frequency proportional to this current. The ...
1
vote
2answers
93 views

SparkFun Sound Detector Circuit Analysis

I would like to request some help in analyzing the op-amp circuit used by SparkFun here. I'm particularly interested in the pre-amplifier portion of this design. The write-up included by SparkFun ...
-2
votes
4answers
144 views

Can I electronically substract an audio signal from an other one?

I encountered a little tricky situation in one of my project. I have two audio signals, A and A+B on two different wires. I would like to know if there is a solution to electronically retrieve the B ...
1
vote
2answers
77 views

Can I change op-amp supply voltage without affecting circuit behaviour

I am working on an audio project which is based upon various sections of several different schematics from various old musical instruments. I want to make a test board that has multiple different ...
2
votes
2answers
95 views

Feasibility of custom parabolic mic (amplified, bandpass filtered) for use with mobile phone app [closed]

I am not an electrical engineer, but I am up for a challenge and this is my first venture into electrical engineering. However I am beginning to think this may be a step to far! As a hobby I survey ...
3
votes
1answer
167 views

Enhancing the bass response of an audio isolation transformer

Below is a simple buffer circuit using an isolation transformer : The green trace is the output of the transformer and the blue trace is the input signal (20hz to 20Khz sine wave). As you can see the ...
0
votes
2answers
164 views

Ticking noise from guitar pedal attempt

I am working on a tremolo guitar pedal circuit. A tremolo pedal basically attenuates the guitar signal using a pattern. Most tremolos use a combination of LEDs and LDRs to do this, but since I do not ...
0
votes
1answer
210 views

Amplifying PWM Audio with an OpAmp

I have an 8 Ω speaker and a Raspberry Pi. To play sound, I can connect the Raspi directly to the speaker, which works, but with very limited volume. I assume this is because of the 3.3 V PWM output by ...
0
votes
2answers
60 views

Is it better to control an amplitude of audio signal or gain?

I'm creating simple headphones amplifier with an opamp (basic non-inverting config with RC high-pass on NI) and I wonder, what's better - to control an amplitude of input signal, or a gain of an opamp?...
2
votes
1answer
117 views

OpAmp choice and circuit configuration for DAC amplification to speaker

For a school project we're using a uC with a DAC which outputs values between 0V-3.3V, which we want to amplify and feed into a speaker. We haven't settled for a particular speaker but considering it ...
1
vote
1answer
138 views

Understanding Audio Amplification with OpAmp

I have what I believe to be a fairly simple schematic, as shown below, to take either a PWM signal from an AVR board to play a song/alarm, or radio signal. I'm connecting both of these with a ...
2
votes
1answer
619 views

Reasons for choosing a transistor instead of an op-amp as a buffer

I have often seen circuits for guitar pedals that use an emitter-follower configuration as the input and output buffer (see example below). If an op-amp can provide a greater input impedance / lower ...
1
vote
2answers
195 views

Is there a difference between specialized audio amplifier and general op-amp silicon?

I've been doing some research into creating a DIY audio amplifier from line-level inputs to speaker level power. I found a guide centered around the LM386 Low Voltage Audio Power Amplifier on YouTube ...
2
votes
0answers
142 views

Can I replace electret microphone with audio connector and expect similar results (sound levels)?

Last night I built a circuit that allows me to obtain sound via a SEED Grove Sound Sensor and input it into my MKR Zero for frequency analysis. It's as simple as this: simulate this circuit – ...
0
votes
1answer
65 views

What's this amplifier filter configuration?

I've come across an audio amplifier circuit that contains this following configuration: I recognize R1,C1, and R3 to be part of a first order high pass filter, but I'm not sure what C2 and R2 are for....
1
vote
1answer
166 views

Opamp Design for Low Impedance Sources?

I am terribly confused ... I tried myself at building a low impedance guitar pickup some time ago. Quick LowZ Pickup Intro Basically just two loops of aluminium with two magnets, a humbucking guitar ...
1
vote
0answers
274 views

Audio DC Offset

I want to make an audio processing device using a Teensy and I want to run an analog signal into it. My background is in audio programming, so electronic circuits are new to me. I realise audio is an ...
1
vote
0answers
73 views

Can this circuit be simplified?

The circuit is a LPF with a buffer stage in front of it that uses a linear pot. to control gain & attenuation. The setup is such that the response of the linear pot. is similar to a log. pot.. A ...
0
votes
1answer
243 views

Sound Chip Audio Amplification Circuit YM2612 + TDA1308

I've been working on a project for connecting a Yamaha YM2612 to an arduino and triggering sounds to be played from the chip. I'm having trouble on the audio part of the circuit. I've worked out a ...
0
votes
0answers
105 views

Low-Pass Filter Selection and Placement in Active Noise Cancellation

This continues in the same vein as my previous question - I'm working on an Active Noise Cancellation circuit to get rid of highway noises in my bedroom. Based off an ANC circuit pictured below, I ...
1
vote
1answer
405 views

Simple audio equalizer design: One filter is sending all the other signals to ground

I’m designing and building an audio equalizer with active frequency filters for my school project and I thought the base design was completely functional until I decided to simulate it on Proteus VSM. ...
2
votes
1answer
173 views

Audio Transformer output straight into an opamp?

Below is a circuit I'm working on. It's a guitar input buffer featuring transformer isolation. The transformer I'm using is pretty expensive and should be fairly linear, but I decided to add a graphic ...
3
votes
2answers
2k views

Unbalanced to balanced audio signal conversion

When I was looking for some information how to convert unbalanced audio signal to balanced, it was hard to find info other than "use transformer" or "buy X device to do this". Then I found this ...
1
vote
1answer
148 views

Precision Rectifier Circuit to detect peaks

I have a question about speed at detecting peaks. Essentially, my question is that I have a precision rectifier with a capacitor equipped to the end of it to smooth the incoming full bridge ...
1
vote
1answer
221 views

Odd distortion in op-amp circuit for audio amplification

I'm new to electronics, so I apologize if this is simple. I'm trying to create a simple amplifier mainly for a guitar input, but testing it with an output and input from my sound interface. The ...
0
votes
2answers
195 views

Replacing Electret Microphone with Dynamic in Velleman Voice Changer Circuit

I am attempting to build this circuit: https://www.velleman.eu/downloads/0/minikits/manuals/manual_mk171.pdf the MK171 Velleman voice changer, but with a 1/4"mic socket for a dynamic mic instead of ...
1
vote
1answer
132 views

Amplify 1W output to 3W

I'm trying to build an audio circuit using an WM8960 chip from Cirrus Logic based off a 2 mic Raspberry Pi board from Seeed studio. The chip outputs 1W per channel into an 8Ohm load but I'm finding ...
0
votes
2answers
89 views

Is there such a thing as a fully differential line driver?

I'm looking to find something similar to the TI drv134 (http://www.ti.com/lit/ds/symlink/drv134.pdf), but then with differential inputs instead of single ended. Is there even such a thing? I can't ...
1
vote
2answers
400 views

Why LME49710 does not perform at least as good as LM358 for audio mic op-amp?

I built a hobby mic op-amp circuit as described here: It gave me a pretty ok result: Now I replaced LM358 with LME49710. The circuit is the same, except from the wiring to the LME49710 pins (LM358 ...
-3
votes
2answers
69 views

Convert 'beep' to 'click' sound [closed]

I'm currently using a metronome with a 'beep' sound that I find quite annoying. I prefer the standalone metronome to a phone app but there's no way to change the sound it makes. Is there some way I ...
0
votes
1answer
124 views

Auto Gain control circuit idea

I am trying to make an Auto Gain control circuit. Having any input source's voltage the same. For example my latop outputs around 1.36Vrms @ 1khz and my iPhone outputs around 0.962Vrms @ 1khz ...
3
votes
2answers
267 views

Filtering capacitor only adds noise in a rail-splitter

Say I need to make a very low-noise signal inverting schematic. For that I came up with the schematic below - the U2 is a low-noise opamp in an inverting configuration, and the schematic around U1 is ...
1
vote
2answers
328 views

Finding the transfer function of an non-inverting audio op-amp

I am just doing some independent re-search for myself in audio amplifier (CHIP AMPS) such as the LM1875. I want to learn more about how to compensate for audio chip amps and how their bode plot ...
0
votes
1answer
155 views

Op-amp control theory

back at it again trying to use your genius brains. I have been trying to teach myself audio amplifier design. The big road block I am getting into is the control theory part of it, meaning how does ...
0
votes
0answers
115 views

Building a simple line out from a mcu DAC

I'd like to get audio (specifically a line out) from a Cortex-M4 10 bit DAC (LPC-4337). The dev board I'm using already has a 470 Ohm resistor in series with the DAC. Since I've never worked with ...
1
vote
1answer
214 views

Common audio signal voltage range on Line out connector

What is typical audio signal voltage range on Line out connector of consumer electronic devices? (Vmin/Vmax) I need specify Input voltage range to calculate op-amp. ...
0
votes
0answers
43 views

What's the maximum supply voltage for a OPA2134PA?

I built a MOSFET driver using a TI 741 op-amp, sounds like garbage - because you know... its a 741. I decided to continue my endeavors and purchase some better preamps and settled on a half-dozen TI ...