1. olivee.almaraz

    Would running a 12ax7 vacuum tube preamp without the tube burn something?

    I have a hybrid guitar amp that has a single 12ax7 in the preamp section and a class A-B solid state power amp section. I've been using it only as a power amp (I connect an external preamp to the "return" of the effects loop, completely bypassing the integrated preamp) and I recently noticed...
  2. L

    Balanced Audio Preamp Circuit

    I tried to make a preamp circuit but I'm not getting any output at all. The simulation on LTSpice seems to work well. The Op Amp I'm using is LMV821 datasheet I'm using a balanced dynamic microphone Zener Diode is 5V1. I don't mind if its noisy as long as I get a some sort of amplification from...
  3. C

    Microphone Filtering and Blocking

    Hello Everyone, I have a quick question about my audio section I am working on with a microphone. I have attached a screenshot of my setup. I am debugging the circuit in a couple of different areas and keep running across the same issue and I am not sure why....granted I am new at this stuff...
  4. C

    Discrete low-noise preamp for opamp.

    I'm designing some audio-frequency instrumentation for my workbench and am using TL074s for most opamp requirements. One section requires microvolt measurements and noise is therefore an issue. It's often difficult comparing opamps on noise and other figures because they're often stated...
  5. J

    Tips for bipolar power supply

    Hello, I need to design a linear regulated supply to power an dac output stage based on op amp. It must be a negative + ground + positive one. The problem I encounter is that I don't know wich topology to select between the first and second arrangement. I suppose that the first one induce a...
  6. J

    Solar Guitar™ prototype

    Hello, I am building Solar Guitar™ prototype, an eco-friendly, self-sustained musical instrument solely powered by the Sun: https://patents.google.com/patent/US9905213B2/en 10-15 watt, 2 speaker stereo guitar amplifier with reverb/chorus/delay/overdrive will be installed into the guitar’s body...
  7. E

    Audio Preamp Circuit for a Microcontroller

    I made a pre-amp audio circuit but it doesn't seem to work. I want to amplify an audio signal so that it has a DC offset of 1.8V. I tried to simulate a similar circuit in KiCad and the simulation seems to work ok. Below is the circuit I designed and assembled. On the scope, the voltage is as...
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