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Posts tagged “power supply

SMPS for B+?

People hate SMPS. “Too noisy”, “All that hash will kill the music”. It is time to see if they are right. Show me another supply that can provide over 300mA of current at 800V+ all while having an output impedance of less than 10 ohms!

Here is a video of the SMPS supplying 770V B+ and -96V bias for my 826 IT GM70 breadboard amp. YouTube Video

EDIT: Well, once again I am late to the party. Way back in 2009 Ed Brown of diytube.com had the same idea. He didn’t stack as many, but the concept was proven valid with just six units in series. See more HERE.
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Greenvalve Luddite 2 10 Amp

Have you ever been sitting at home, listening to your stereo and thought “I wonder if this is as good as it gets?” Well, I have. I guess it doesn’t matter much since the idea of what is best is different to every ear. But that hasn’t stopped me from trying! I will say that this is one of the best sounding amps in existence.

Shown below is the schematic of my finest design. Although choke loaded VT-25 driving VT-25 finals is fantastic, it sounds best using the stunning RCA 210 driving another RCA 210. For those who know, they know this is special. This is my gift to you, the DIY guy with great ears.

I have changed the amp to use filament current bias on the input tube, while allowing a choice of driver tubes. The VT-51 (841) tube is a detail monster. If you are into vinyl the 841 driving the 10 is something you’ve just gotta hear!  An added bonus of using the 841 is slightly higher gain, but because of less current draw the B+ ripple is lower. However, my favorite is the schematic shown… a 10 interstage coupled to another 10.

How can I say that this is the best sounding amp in existence? Well, I can not. I haven’t heard them all yet. But compared to every amp I have heard so far… things look pretty good!

This amp would make a nice front-end for GM70 finals wouldn’t it? 😉

I wish you could hear this amp for yourself. The best I could do is make a few videos of it. They do give a sense of how well the amp images. For your entertainment… Link to Videos of the Luddite 2 10

The photos below show the amp at various stages of its development. It no longer uses the Mundorf SGO caps for coupling, instead using Hammond 126C 10K:10K interstage transformers.

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