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GB: Round #2; Fo-Felix EMI Filter for AC mains 120/230v; By Folsom

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The first round was gone almost in the snap of the fingers.

So over the years people have asked about the old version, made by someone else.

It's probably time for an updated one. This one is a bit different. You may notice it does not have following capacitors after the choke. I have tried both ways, and my preference is strongly without the following X2 capacitors. Also the capacitors prior to the choke are not varied in size because overall capacitance is more important - and they won't randomly resonate with each other.

The other major change is the addition of bypass resistors for the chokes. These don't ruin the filtration, but they do a good job of quieting the chokes that can get excited by different combinations of things on the mains.

Round #2 won't need nylon washers on the top and bottom of the PCB (screws were violating the clearance too easily on R1).

Fo_Felix_R2_Public_preview2.png


Gen1 w/comoco's
IMG_1974_1_22.jpg


Here's how it is different in settling time from the original.
Fo_felix_vs_felix.png


Here's a comparison between resonances.
Fo_felix_vs_felix_resonance.png


*2oz copper PCB (1oz is standard)
*Weco 983ZD terminals, copper alloy and can accept 2 wires for daisy chain. These are also safer, particularly if you use solid core wire that otherwise likes to make cold solder joints you can't see.
*X2 rated capacitors for safety, 4x 0.47uf. They are alternated for CFC (capacitor field cancellation).
*Discharge resistor for X2 capacitors
*Coilcraft Comoco choke w/fuse or Bourns 8120/8121-RC choke w/o fuse & 15/16A/20A(*) max sockets
*Fuse clips are beryllium copper (good for 30A)
*120/230v operation (parts & pcb)
*Mounting holes are sized to work nicely with M3 screws and standoff kits
*Size: 2.25x4.25in

The Weco 983ZD are preferred terminals, but not always available as individual sale. For this reason I'm going to include them in the price of PCB, so that I can meet min order requirements for them and save everyone the shipping.

Price: $13ea ($9 per filter board same as original, $2 per Weco, 2 needed per board)

Shipping: $8 US, priority USPS box
$15 CAD
$16 General international padded envelope
If ordering over 4x boards there may be an additional $10, depending on destination.

Need 32 filter board commitments to order.

**** For anyone with the originals that was not satisfied with having to use nylon washers (that I refunded $1 per board for to buy them) just tell me and I'll make a note to reserve them out of the printed lot, no need to commit to buying more****

1MOR 5
pcgab 2
paulab 3
hkknudsen 3
tripped 2
Paul Hirst 6
Dhsettim 4
vanofmonks 2
AmpUtator 2
Audiogurujax 10
passive420 4
GhostMM 3

Pictures of Enclosure:



 
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Quote.

*Coilcraft Comoco choke w/fuse or Bourns 8120/8121-RC choke w/o fuse & 15/16A max sockets
In-Quote.


Destroyer OS:
I was just getting ready to order 15 or 17amp fuses for the Bourns 8120-RC coils. Why no fuses if using the Bourns?

Are you saying to jump the fuse on the boards if Bourns are being used?

What do you mean by 15/16A sockets?

Sorry, just want to make sure I understand correctly.
 
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Quote.

*Coilcraft Comoco choke w/fuse or Bourns 8120/8121-RC choke w/o fuse & 15/16A max sockets
In-Quote.


Destroyer OS:
I was just getting ready to order 15 or 17amp fuses for the Bourns 8120-RC coils. Why no fuses if using the Bourns?

Are you saying to jump the fuse on the boards if Bourns are being used?

What do you mean by 15/16A sockets?

Sorry, just want to make sure I understand correctly.

Because the Bourns are rated for the full capacity of the socket that feeds them. The Comoco's are fused because they'll melt if they are drawing too much current, and it's possible to do so without triggering the breaker. These decisions are based on people using them in "power strip" type situations, not within say an amplifier where you may choose to have a fuse that is accessible on the back (in which case it's your option if you have the understanding to modify your fo-felix, if you're using a different fuse holder)

All sockets with blades like this are 15A, and in the EU they go up to 16A (13A is common)

images


Some people with custom romex lines may want to use the 8121 at 20A if they're using a 20A socket.
 
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Is anything gained from putting them in series, for example 8121 and the smallest one (well, several of them)? Or can the 8121 just as well be omitted then?

I suggest subjective testing on that. I've seen people put two in a row before. I believe one is a manufacturer. You're adding more inductance and more attenuating capacitance, but there may be some consequences to the complexity of the AC that might be audible but maybe not. You have to decide if it's simply "better".

You can do it technically, for sure.
 
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