• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6V6 line preamp

diyAudio Chief Moderator
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Hey Salas, do you still like the Maida regulator PSU for these? I'm currently working on PCBs for power supplies and was thinking of putting one together as a spiritual companion to the other boards.

I'm also putting together a simple mosfet ripple filter PSU on a 50x50mm PCB as well since it's what I use in 75% of my own builds, same basic circuit as the one Pete Millet used in his Engineer's Amplifier, but just with a diode bridge-

It would be easy to start with this and expand it to 50x100mm to work in an LM317T to make a Maida regulator board.
Hi,
Maida measures cleaner FFT grass with more PSRR, cap multiplier has 10dB more hum as it ups output impedance towards the lows. For directly felt noise they are both sufficient. Filter sounds rounder, Maida more neutral. I like both depending on system synergy.
 
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Hmmm.

Sy's Red Light Distrct amplifier turned me on to the Maida and it worked great for me on the screen supplies for pentode amplifiers. Haven't built one in years due to complexity and messy protobJones. The use of an LM317 IC may cause some folks to turn away, however.

The Engineer's amplifier turned me on to the mosfet filter, and I use it for most of my builds now. I really like it for screen supplies and lower power class A stuff. Dead silent and simple.

I've also used shunt regulators in the past and was happy with them- VR tubes fed by CCS being my favorite so far. There's also the zener types such as the Statistical Regulator by Morgan Jones.

I suppose for what we are doing here they all will work very well, just depends in how complex people want to go.
 
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For the LM317 set up as a current regulator- the formula is easy. 1.25 volts divided by the resistor value in ohms will give you the current, this current multiplied by the 1.25 volts will give you the resistor dissipation in watts- you then derate the total wattage in order to keep the resistor from running too hot, a common and smart practice is to make the actual resistor wattage 2-3 times higher than needed.

For example, assuming a 2R7 resistor, 1.25/2.7= 0.462. This multiplied by the 1.25 volts is 0.578 watts. So I would use at the very least a 1 watt resistor, but it would be screaming hot. Better yet a 2 or 3 watt so that it will not run too warm. 5 or 10 watt would be lovely.
 
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Thanks Lingwendil, I know and made the maths so the reason I asked.

Salas got the rheostat 3R 5W that kindly sent me time ago and never used.
 

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