DC blockers and mains filters

[2 picoDumbs]

Mindutis has a thermal switch in series with his MOV's, guessing this is to prevent a catastrophic failure of the MOV.
I think this is a good idea.
Maybe 3 MOV's in parallel with a thermal switch on each one.

 

[planet IX]

IMHO one should distinguish surge protection from lightning protection. I wouldn't expect a surge so high, that a fat MOV couldn't handle it. Also I would not put any resistance in series with a MOV - that would probably reduce its effectivity.

 

[2 picoDumbs]

It's a thermal switch not a resistor. A thermal switch should have virtually zero resistance.
I agree with everything you say though.

 

[Destroyer OS]

Here is an example of a mains filter.
Does anyone have any ideas or opinions regarding improving it further.

Yes, you should have joined my Fo-Felix group buy.

Y caps are ok if you run entirely truly balanced and shielded equipment - in theory at least.

 

[2 picoDumbs]

Hahahaha

Well I have only just seen the light.

I will repent.

 

[2 picoDumbs]

Y caps are ok if you run entirely truly balanced and shielded equipment - in theory at least.

Leave out Y caps - Check

I notice medical grade filtered IEC connectors don't use Y caps, but maybe it's a patient safety reason, and not a noise requirement.

 

[2 picoDumbs]

SMOV Thermally Protected Varistors w/ Micro-Switch - Littelfuse | Mouser

Just throwing out bits and pieces for people to comment on

 

[Mark Johnson]

Non-Stocked ; $8.32 qty=1

https://www.mouser.com/ProductDetail/Littelfuse/SMOV25S271MP?qs=CCsEpQXMEEDveNb9I80Y1A==

 

[2 picoDumbs]

Not cheap but maybe they'll last a lifetime.

Still cheaper than this though
Nordost Valhalla 2 Reference Power Cable - Power Cables - Power Products - Hi-Fi Melbourne's best Hifi

Hahahaha

 

[MagicBus]

This is my attempt based on as much I could get from these papers : https://www.schaffner.com/fileadmin...ation_note/Schaffner_AN_RB_common_chockes.pdf and https://www.mouser.com/pdfDocs/schaffner-engineers-guide-designing-emi-filters1-13-17.pdf . It is only built on calculations, I can't measure its performance. The idea was to make it work for both differential and common mode noise, so I used the Y caps. 6,8nF is the max if we are to stay within the permitted 0,5mA leakage current. And since this current adds with multiple filters, only one should be used for the entire system - well, I used two, one for the amps and one for the audio PC. Anyway, when one coil is used, RDC should be very low so these coils measuring a few mH make no practical sense... I built my own with MnZn core which is more predictable in very high frequencies than nanocrystalline and 2,5mm copper wire. Regarding MOVs, my interpretation is that either use only one or none. I omitted them completely and rely on central panel RCD. Additional info here :Questions about IEC inlet filters, again...

 

[2 picoDumbs]

I think the beauty of the MOV is not only do they protect, they also add some level of mains regulation, smoothing out voltage spikes and allowing the circuit to keep operating.
If your AC mains power doesn't suffer from those problems then it won't add much, but it's a nice feature to have.

 

[Destroyer OS]

While it lasts anyways.

 

[2 picoDumbs]

Yeah.
Hahahaha