
Home  Forums  Rules  Articles  diyAudio Store  Gallery  Wiki  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 
Pass Labs This forum is dedicated to Pass Labs discussion. 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
27th December 2006, 10:22 PM  #1 
diyAudio Member

Pass: Constant Current Source Filter Networks
Hello,
just read the paper on firstwatt.com concerning the filter networks for a constant current source amplifier like F1. But I'm a little bit confused about getting the part values. Therefore can somebody explain it to me so that I an verify my thoughts? Let's say, we want to build an 2nd order Bessel filter with a cutoff frequency of 1kHz and 1K ohm load (just as an example). What re the component values? Greets, Raphael 
27th December 2006, 10:42 PM  #2 
The one and only

Referring you back to that article, on fig 5A you see a 2 pole
high pass and low pass network (in series) both of which are set for 1 KHz. You need only multiply the inductance values by 125 and the divide the capacitor values by 125 to scale the 8 ohm load to 1 Kohm. You can use these two networks alone  each does not require the other. The specific alignment of can be tweaked with modest variations, and of course you can multiply/divide values of the inductors and capacitors to scale the filters to other frequencies. 
27th December 2006, 11:36 PM  #3 
diyAudio Member

Ok, thank you Nelson.
I didn't recognized that they are set to 1kHz. So the only way to get the desired Bessel characteristic is try and error unti it fits in? Raphael 
28th December 2006, 07:50 PM  #4 
The one and only

If you are mathematically inclined, you can calculate the
exact LC values. I don't personally get excited about this when we are dealing with loudspeakers  precise filter types are not usually optimal due to the vagaries of the driver response. 
Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Constant Current Source article (Old)  tvi  Solid State  12  9th June 2012 10:33 PM 
Constant current source, am I missing anything...  gmphadte  Power Supplies  4  3rd August 2007 05:07 AM 
constant current source  hacknet  Solid State  19  13th March 2006 03:46 PM 
Constant current source for Clone  audioandy  Chip Amps  2  27th January 2004 12:55 PM 
Constant Current Source Circuit  mrfeedback  Solid State  8  22nd April 2002 06:07 PM 
New To Site?  Need Help? 