I have a TDA2030A based amplifier that should make a decent headphone amp except that its gain, at about 32 dB, is way too high.
It is easy to change the gain setting resistor or even put in a switch to change the gain from say 10 to 15 to 20 dB for proper Headphone use. But there is a problem.
The TDA2030A data sheet says the chip needs to run at a gain in excess of 24 dB to maintain stability. That is too high for low impedance high sensitivity headphones. The volume control will never be in a linear tracking region.
A resistor could be placed in series with the output. But that destroys damping factor and sound quality. That is not an acceptable solution.
However, if you can get stable operation at lower gains not only can the amp be used for headphones but the necessary addition of feedback should improve distortion specs as well. It is a nice goal for a very available OPA.
Meier Audio uses the TDA2030A in their Corda Brick. It has switchable gain of -1 to +14 dB. So how do they do that with the TDA2030A?
Anybody got a working circuit that gets the TDA2030A down to a stable (switchable?) gain of 10-15-20 dB?
Suggestions?
Thanks
It is easy to change the gain setting resistor or even put in a switch to change the gain from say 10 to 15 to 20 dB for proper Headphone use. But there is a problem.
The TDA2030A data sheet says the chip needs to run at a gain in excess of 24 dB to maintain stability. That is too high for low impedance high sensitivity headphones. The volume control will never be in a linear tracking region.
A resistor could be placed in series with the output. But that destroys damping factor and sound quality. That is not an acceptable solution.
However, if you can get stable operation at lower gains not only can the amp be used for headphones but the necessary addition of feedback should improve distortion specs as well. It is a nice goal for a very available OPA.
Meier Audio uses the TDA2030A in their Corda Brick. It has switchable gain of -1 to +14 dB. So how do they do that with the TDA2030A?
Anybody got a working circuit that gets the TDA2030A down to a stable (switchable?) gain of 10-15-20 dB?
Suggestions?
Thanks
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