Doesn't depend on the psu...What size transformer and caps in the PSU?
I have this hum even if there is nothing attached to the filters..
Today I used some car dampening on the case and it is not so loud anymore...
Next what I have to check if one of the coils has loose wire.... And will put some glue on it.
I too don't believe that there is an error in the design...
And the amp I use with the filter is a 125Asx2 from B&O...
Interesting is that if I switch a relay there with the 220v the noise gets louder....
A group buy for coilcraft CMC's would be great, the sample 'AL' versions do not fit the boards...unless the new batch boards can be modified with extra holes to fit the samples 😉
It is difficult and expensive to just get a couple direct from Coilcraft to the UK and cannot seem to find a distributor to EU.
These are good for my individual devices:
Q4007-A - 5A
P3717-A - 3A
It is difficult and expensive to just get a couple direct from Coilcraft to the UK and cannot seem to find a distributor to EU.
These are good for my individual devices:
Q4007-A - 5A
P3717-A - 3A
the sample 'AL' versions do not fit the boards...
Hmm, I have Rev1 and Rev2 boards, P3717-AL, Q4007-AL, and Q4018-AL coils and they all fit both pcb rev numbers.

Hmm, I have Rev1 and Rev2 boards, P3717-AL, Q4007-AL, and Q4018-AL coils and they all fit both pcb rev numbers.![]()
Well that is disappointing to hear, do I have different boards? Not sure what version these are - The text says 'R2'.. so rev 2 I think but they definitely do not fit, so something is up. Maybe I made a mistake...
Can I have your boards 😉
The boards fit the Bourns 17A perfectly but I wanted smaller amperage rating for certain devices.
Attachments
Turn them 90 degrees
Yes the COMOCO's are not turned correctly. But the other torodial one looks correct. It would take a little bit of ingenuity to fit it.
A group buy for coilcraft CMC's would be great, the sample 'AL' versions do not fit the boards...unless the new batch boards can be modified with extra holes to fit the samples 😉
It is difficult and expensive to just get a couple direct from Coilcraft to the UK and cannot seem to find a distributor to EU.
These are good for my individual devices:
Q4007-A - 5A
P3717-A - 3A
Check eBay pricing for sending COMOCOs. They may be much more friendly on shipping.
Yes the COMOCO's are not turned correctly. But the other torodial one looks correct. It would take a little bit of ingenuity to fit it.
Well that makes me the biggest idiot in the solar system... having just got them today I hadn't looked properly. Sorry people.
All is well now. Didn't think of ebay though. Thanks guys.
How can I check soldering iron temperature?
My inexpensive DMM has a small temperature probe that can be used to check temperatures up to 1400F, so the manual say's.
I tried using it on the end of a soldering tip, with my Hakko FX-888D set to 750F and I measured 509 degrees. That's a 241 degree difference.
I'm sure this is not an accurate way to check temperature but do you guy's think it is getting me at least close?
The photo shows 71.4 degrees setting at room temperature which is okay.
My inexpensive DMM has a small temperature probe that can be used to check temperatures up to 1400F, so the manual say's.
I tried using it on the end of a soldering tip, with my Hakko FX-888D set to 750F and I measured 509 degrees. That's a 241 degree difference.
I'm sure this is not an accurate way to check temperature but do you guy's think it is getting me at least close?
The photo shows 71.4 degrees setting at room temperature which is okay.
Attachments
I wouldn't worry about it. Just set it and try to make it work well. If you need more heat turn it up.
Coilcraft on eBay
eBay seller motorsportsjs charges less for shipping and about $1 less for each of the 3A comocos.
I ordered 3 P3717-A. Each product is made with two E shaped ferrite core halves which are glued together. Upon arrival, I was very surprised that the cores were not properly aligned. All were off by about 0.5mm. But the worse one was off by 1mm, which is a lot for a 12mm thick core. This would result in much larger stray magnetic flux from what is expected to be a high quality (some say audiophile quality) common mode choke.
I suspect these products are seconds or somehow rejects and did not make it as primary stock at Coilcraft and hence are being sold "as is, without warranty" on eBay.
Had I known, I would have sprung for the extra dollar each and bought them from Coilcraft.
Check eBay pricing for sending COMOCOs. They may be much more friendly on shipping.
eBay seller motorsportsjs charges less for shipping and about $1 less for each of the 3A comocos.
I ordered 3 P3717-A. Each product is made with two E shaped ferrite core halves which are glued together. Upon arrival, I was very surprised that the cores were not properly aligned. All were off by about 0.5mm. But the worse one was off by 1mm, which is a lot for a 12mm thick core. This would result in much larger stray magnetic flux from what is expected to be a high quality (some say audiophile quality) common mode choke.
I suspect these products are seconds or somehow rejects and did not make it as primary stock at Coilcraft and hence are being sold "as is, without warranty" on eBay.
Had I known, I would have sprung for the extra dollar each and bought them from Coilcraft.
Attachments
I would contact the eBay seller. eBay much nicer to buyers than sellers about defective items or such.
I don't think the results will be quiet as drastic as you may think. But thank you for bringing this to our attention.
Do you think you could break it free and re-glue it?
I don't think the results will be quiet as drastic as you may think. But thank you for bringing this to our attention.
Do you think you could break it free and re-glue it?
Looks like coilcraft are now made in China and not Mexico. I wonder if this has anything to do with it.
I will post a pic once I remember how to do it. : (
Paul
I will post a pic once I remember how to do it. : (
Paul
It looks like the one with the original misalignment is from Mexico.
The one on the left I just received is from China. I purchased it directly from Coilcraft.
The one on the left I just received is from China. I purchased it directly from Coilcraft.

Last edited:
It looks like the one with the original misalignment is from Mexico.
The one on the left I just received is from China. I purchased it directly from Coilcraft.
Hello Paul,
Did you purchase the Mexico P3717 from eBay?
- Home
- Group Buys
- GB: Round #2; Fo-Felix EMI Filter for AC mains 120/230v; By Folsom