LuminAria Article Available

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Pass DIY Apprentice
Joined 2001
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Good news, AudioXpress will feature LuminAria in this week's Audio Voice e-newsletter.

That means you'll be able to read and download the original article here:

You Can DIY!: LuminAria SIT Preamplifier | audioXpress

I'd like to thank the editors at AudioXpress for making this available and I hope you will be encouraged to show your support by subscribing.

I hope to have a new SIT preamp article for you this winter.

Mike

:)
 
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Pass DIY Apprentice
Joined 2001
Paid Member
You're certainly welcome. My pleasure :)

When I did this, it was meant to be a "show the work (design and calculations)" piece, so there are some things I ultimately did differently for my own copy. The main difference being fixed bias, which Tim has done here as well to nice effect.

Also, just in case it comes up. The PCB's shown in the article have never been publicly available. They were special prototype boards I used that had all kinds of extra jumpers and pads so I could try a lot of different stuff, so I don't intend to release them. Maybe I'll do one for the next one...
 
Pass DIY Apprentice
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You're welcome. Glad you enjoyed it. I'll check on that. It's been a few years now :) I doubt I would have gone as high as a 20k source impedance. What music source are we planning to use? The eff. input capacitance is around a hundred pf, so you can figure out the FR from there.

In actuality, the buffer is made this way, because it was intended to (also) work with a certain unobtainium part I had on hand in the same circuit with some resistor value changes. That part has an input capacitance of a couple pf.
 
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You're welcome. Glad you enjoyed it. I'll check on that. It's been a few years now :) I doubt I would have gone as high as a 20k source impedance. What music source are we planning to use? The eff. input capacitance is around a hundred pf, so you can figure out the FR from

That would be 50 percent of a 47k pot hung in front of the buffer :D

It's not the FR per-se that is of direct interest but the impact of the fet's varying input capacitance on THD if a reasonably high impedance pot is used.
No worries though - enough hints so far from you so that I can do the rest ;)
 
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