• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

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

Hey everybody!

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.

Higher-Res image
Fo_Felix_public_previewcrop3.png


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 (even of different sizes, 12-20ga). 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 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 international padded envelope

Need 32 filter board commitments to order.

AmpUtator 2
C37 2
torb 3
wushuliu 1
KaffiMann 3
drkingweeb 2
limits 3
ckwong99 4
ericimage2 5
Mcluxun 4
wcwc 5
vinylvalet 4
dhsettim 4
bvtrinh 6
shattered_dream 3
 
Last edited:
The CMT4's are not going to work right.


Is it due to the spacing or are the CMT4's not right for a Felix?

I don't have the technical savvy you do, can you shed some light on the 4s?

I've been hoping to use my two CMT4-17-9L (9 amp) and two CMT4-10-15L (15 amp) coils someday. They are 1.500 by 0.900 spacing.

I suppose I could purchase 4 blank boards and use them that way?

Here's a few pics of my Bournes and CoilCraft units.

The CMT4's are much larger.
 

Attachments

  • IMG_0356.jpg
    IMG_0356.jpg
    227.6 KB · Views: 2,858
  • IMG_0364.jpg
    IMG_0364.jpg
    235.3 KB · Views: 2,817
  • IMG_0369.jpg
    IMG_0369.jpg
    296.8 KB · Views: 813
They push the fuse right off. In your photo with the Comoco, the comoco is turned 90* off of the mounting direction.

The board size could be increased a lot, and I'd make it so all of the CMT4's were fused since you can go under ampere with them in the same holes. Where as the current ones simply work, and are easily available.

A project board might be the best way to use the CMT4's, unless a flood of people want to use them, then I could make another board.
 
They push the fuse right off. In your photo with the Comoco, the comoco is turned 90* off of the mounting direction.

The board size could be increased a lot, and I'd make it so all of the CMT4's were fused since you can go under ampere with them in the same holes. Where as the current ones simply work, and are easily available.

A project board might be the best way to use the CMT4's, unless a flood of people want to use them, then I could make another board.


So the layout is turned from by attached pic. I see now.
 

Attachments

  • IMG_0372.jpg
    IMG_0372.jpg
    220.8 KB · Views: 1,205
So the layout is turned from by attached pic. I see now.

I'm looking into the CMT4 some, because of some of its attributes. I'm also looking at Wurth.



I guess a big question is, what would people like to see perhaps, instead of just the current updates? The Bourns have been known to be pretty undetectable compared to others. But it may be possible to increase the distance from saturating with some other chokes. They however will cost more.

I'd recommend amps that use no more than 4.25A during regular playback (200-255wpc for 120v for class AB) with the 17A bourns, but can go larger with the 8121. Why? Because it prevents any possible saturation during the most intense peaks.
 
Last edited: