CFexpress card reader with magnetic property - is it a risk to external hard drive if they come in contact?

If you would like to post, you'll need to register. Note that if you have a BCG store account, you'll need a new, separate account here (we keep the two sites separate for security purposes).

Ivan Rothman

Ivan Rothman

Well-known member
Supporting Member
Marketplace
Member's gallery
I have a Delkin CFExpress Type B card reader which works very well. And it is quite compact. But I had also gotten a ProGrade Digital CFExpress reader because it also had an dual slot for reading SD cards. But then I recently read that the ProGrade reader was magnetic and could damage a hard drive if it came in close proximity to it.
So I took the ProGrade reader and indeed did find that it was a fairly strong magnet when I brought a metal object next to it. Not the case with the Delkin reader.
Since I travel with my card readers and my external SSD hard drives in the same pouch, I worried about damaging the hard drive data. I don't know if SSD drives have the same susceptivity to magnets as non SSD drives. But out of caution, I think I will not be traveling with the ProGrade reader for now.
 
Member's gallery
This is the thread…

DO NOT DO THIS!!!

So I was working on my computer last evening and I disconnected my Pro Grade CFEXPRESS B/SD card reader. I put it on top of a sheet of paper that was on my desk. After a few minutes I heard a strange clicking sound that kept getting louder and my computer was acting strange. I probably would not...
bcgforums.com bcgforums.com
 
Member's gallery
If you end up looking for an alternate, I have a Lexar dual SD/CFE Type B reader that does not have a magnet. I have not pushed it for long periods of time, so I cannot tell you how it handles heat, but so far, so good. And it was affordable when I purchased it.

Good luck,

--Ken
 
Member's gallery
Any thoughts on the OWC Atlas CFexpress 4.0 Type B? I just ordered it yesterday to replace my old Sony reader which I've been having some trouble with lately.
 
Member's gallery
FWIW, in another lifetime I used to work in the recording industry and had tremendous experience in degaussing and processing many miles of magnetic tape. Anyhow, modern HD's are relatively resistant to magnetic fields and even close proximity with common magnets will not affect them. For reference a kitchen magnet produces a magnetic field of around 10 gauss and one would need 500-800 kitchen magnets to potentially disrupt a hard drive. That's not necessarily true of high gauss, rare earth types of magnets like N42 or N52 varieties which can easily exceed the shielding of HDD's. Without knowing the relative magnetic field of the reader, it would be impossible to speculate on whether it is potentially harmful. BTW, magnetic fields don't disrupt SSD's or CFE's.
 
Member's gallery
ajrmd said:
FWIW, in another lifetime I used to work in the recording industry and had tremendous experience in degaussing and processing many miles of magnetic tape. Anyhow, modern HD's are relatively resistant to magnetic fields and even close proximity with common magnets will not affect them. For reference a kitchen magnet produces a magnetic field of around 10 gauss and one would need 500-800 kitchen magnets to potentially disrupt a hard drive. That's not necessarily true of high gauss, rare earth types of magnets like N42 or N52 varieties which can easily exceed the shielding of HDD's. Without knowing the relative magnetic field of the reader, it would be impossible to speculate on whether it is potentially harmful. BTW, magnetic fields don't disrupt SSD's or CFE's.
Click to expand...

I've heard the same thing - that there is no risk of damage or data loss and that it takes a much stronger magnet to have any impact. I've heard this specifically from one of the companies that makes memory cards but I don't recall which one.

There are a number of places where we have magnets. The MagMod system uses magnets to attach accessories. The RRS and other brackets have a magnet that holds a small wrench. There are magnetic systems holding filters on your lens. The ProGrade readers are designed to use a magnet and attach to your computer. You actually put the card in the reader just a small distance from the magnet. There are even magnets used to hold bag flaps shut on camera bags and computer bags.
 
Member's gallery
It is not going to be a strong enough magnetic field to damage a hard drive that is protected by its metal case. Way back in 1982 the Osborne computer had a slot right above the CRT and if anyone put a floppy disk with its plastic body in this spot it could corrupt the data and cause problems.

It is the old CRT monitors and large audio speakers that have strong enough magnets to cause problems.

Main causes of data sectors being damaged is static electricity which is much more of a problem today with chips using smaller and smaller circuitry and there is very little space between the circuits/gates/transistors. We don't see it much with laptops as they are protected with their AC to DC bricks for the most part.
 
You must log in or register to reply here.
Back
Top