Krell KSA 50 PCB

It depends if you want to go "up" of "down" in voltage
To to up yo need some sort of voltage doubler but it may end to high for your needs.
To go down you just need a voltage regulator and in both cases there are plenty of diagrams/projects online.
I remember a project that used a small VA transformer to "lift" the voltage for the preamp stages but that was over 25 years ago and can't find it anymore.

Good luck
 
Hi, I'm trying to build a ksa-50 on a delta-audio board. But I can’t figure out how to make two different voltages from one source. Couldn't find it on the forum. If anyone has a diagram of such a power supply, please post it.
Can you be more specific please? Do you mean + and - voltages lower than the raw psu output as it sounds like you want + and - from a single (+ve) supply.
 
I have two transformers, one per channel. voltage 230/ 36-0-36, 250W. and the question is whether it is possible to obtain two voltages from one such transformer. Probably someone assembled it using a delta audio circuit, pre stage voltage 50v, output stage 47v. I was hoping there was a ready solution.
 

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Here is my KSA50 schematic with voltage references if anybody is using a similar voltage. I am getting right at 50 watts/RMS/8 ohm load.

My KSA50 amps use +/- 33.5VDC, so in order to keep the zener diode circuit from possibly falling out of regulation, I am using 910R instead of 1k5 for R1 & R38. This allows approximately 7mA to flow through the circuit (3mA for the LTP and 4mA for regulation).

I also replaced the emitter follower (emitter resistors) R5 & R42 3k3 with 1k2. This allows approximately 1.3mA instead of 425uA to flow through the emitter follower.
in your schematic, you separate Agnd with Vgnd, where is the source from ground output/speaker, thanks in advance
 
Here is my latest schematic based on my power supply voltage. A few component values are optimized for my power supply voltages.

Some AP measurements as well.

1708192801669.png


1 Watt/8 Ohm
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1 Watt/8 Ohm Frequency Response (Yellow) vs THD+N (Green)
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Signal to Noise/1 Watt (8 Ohm reference)
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5 Watts / 8 Ohm
1708193107176.png


Power out / 8 Ohm
1708193115119.png
 
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