I'd like to build this amp, I already got all parts needed except the choke. Hammond 193V will be too expensive for shipping cost and extra customs fee. I'd like to ask local builder to wound the choke with m6 core.
My question is what the minimum inductance required? What is the formula to calculate it?
Thanks
My question is what the minimum inductance required? What is the formula to calculate it?
Thanks
Depends on how low the amp needs to cover. If it is a full range amp then Michael recommended to aim for at least 100 mH. If it is just for the midrange or tweeters then you could get away with less.
In my similarly choke loaded amps I run 193V for mids and 50 mH 193Ts for the tweeters, working great so far.
In my similarly choke loaded amps I run 193V for mids and 50 mH 193Ts for the tweeters, working great so far.
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Inductor works on any grade, the grading just determines what voltage you need at the gate to conduct X A of current. Some grades (KD) might need say -2V for 2 amps, which you get with a 1 ohm source resistors. My KE I tested needed ~ -4V if I remember correctly so I had to build a negative supply.
If you do build a negative supply that you can control by pot from say 0 to -10V then you should be able to use pretty much any grade. You can mix grades too on each amp as you can just set different bias voltages.
Also, inductors are awesome! I'm using the Hammond 193V on my midrange amps and 193Ts on my tweeter amps.
If you start at 0V then you will likely toast themOllBoll , thank you for the answer. I have all the necessary parts to amp and I will build it .
Another question , when done have it set to 0v and go negative voltage for adjusting , or start -10V and go to reducing 0v ? Just not my toast SITs
best regards
The SITs conduct more current the with higher voltage at the gate. When stating you want to conduct minimum current so set the voltage supply to minimum voltage. Then you increase voltage at gate until you have the desired current flowing through the device. If you have 193V and use 24V supply around 2A works great.
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All that info is in the vgs curve, which shows current through device if voltage at source is X in relation to drain.
http://www.diyaudio.com/forums/images/articles/Rothacher/s2k82a.jpg
On this device a gate equal to source thus 0V difference would at 20V conduct about 5A which is a bit too much so we need that negative supply.
http://www.diyaudio.com/forums/images/articles/Rothacher/s2k82a.jpg
On this device a gate equal to source thus 0V difference would at 20V conduct about 5A which is a bit too much so we need that negative supply.