The solution is explained in this blog post : http://www.diyaudio.com/forums/blogs/abraxalito/862-flattening-nos-droop.html
I've built it using TDA1545A but there's no reason it wouldn't also work with TDA1541A. It does require a way to divide the current output on the two additional DACs though which requires some ingenuity. One way to do it is to divide the I/V resistor into 3 parts.
I've built it using TDA1545A but there's no reason it wouldn't also work with TDA1541A. It does require a way to divide the current output on the two additional DACs though which requires some ingenuity. One way to do it is to divide the I/V resistor into 3 parts.
Start with the known-good basics
Damper diodes or tube rectifier into CLC (aka Pi) filter. And run AC heaters.
if you can't find an inductor use a resistor dropping at least 20V.
Hexfreds if you must use hard rectification;
You can mess around with other architectures later.
Damper diodes or tube rectifier into CLC (aka Pi) filter. And run AC heaters.
if you can't find an inductor use a resistor dropping at least 20V.
Hexfreds if you must use hard rectification;
You can mess around with other architectures later.
KISS
Noise and simplicity.
Rectifying AC creates noise which may get from the heater to the cathode. Batteries have their own problems.
If the valve has good heater noise rejection; then there's no point in going away from AC. Which is conveniently the simplest thing to build.
Given that we're talking about low level signals we want to minimise the noise sources.
Noise and simplicity.
Rectifying AC creates noise which may get from the heater to the cathode. Batteries have their own problems.
If the valve has good heater noise rejection; then there's no point in going away from AC. Which is conveniently the simplest thing to build.
Given that we're talking about low level signals we want to minimise the noise sources.
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