Topband: Ferrite Cores

[Bill Wichers]

My cores arrived yesterday. I haven't done any electrical testing on them yet, but mechanically they appear to be fine. They were not "crumbly" as some were concerned about. I don't think they are as high quality as the fair rite cores I've used in the past, but this is based only on aesthetics (the amidon cores I received have some striations in the faces, and will mar fingers if you rub them). I don't think they will be a problem in service. 

My known-to-be fair rite cores from a previous mouser order did not show any striations in the faces of the cores, nor did anything come off on fingers when they were rubbed. They were also #31 mix though, so that might be part of it. I don't have any other #61 cores laying around to try with a "rub test". 

It looks to me that amidon has either switched suppliers or their supplier has corrected the problem that was reported earlier. 

-Bill 

Sent from my iPad

> On Aug 5, 2014, at 3:29 PM, "Bill Wichers" <billw at waveform.net> wrote:
> 
> It sounds like they weren’t properly fired from what he said about them crumbling. That, at least, is an easier thing to look for than a messed up mix. If they have poor QC on these things then I’d be concerned about the “mix #61” not actually being mixed correctly resulting in the cores not having the correct magnetic properties. If I have some time I can put together a test setup for that and check the ones I have coming to be sure.
> 
> That post looks to be several years old so hopefully Amidon has corrected the problem, or otherwise switched suppliers.
> 
>  -Bill
> 
> From: Mike Waters [mailto:mikewate at gmail.com]
> Sent: Tuesday, August 05, 2014 3:01 PM
> To: Bill Wichers
> Cc: topband
> Subject: Re: Topband: Ferrite Cores
> 
> It's certainly possible.
> 
> You can read what he said and see photos at
> http://forums.qrz.com/showthread.php?240056-Need-source-for-Cushcraft-R5-torroids&p=1882177#post1882177
> 
> 73, Mike
> www.w0btu.com<http://www.w0btu.com>
> 
> On Tue, Aug 5, 2014 at 1:54 PM, Bill Wichers <billw at waveform.net<mailto:billw at waveform.net>> wrote:
> Well, I should have them in a few days so I’ll check them out and report back what I find. Maybe Greg just got some from a bad lot?
> FT-240-61 cores. Amidon was $9/ea, Mouser (for the Fair Rite equivalent) was $14/ea.
> 
> Those were the SAME Amidon cores that Greg, W9GB said were crumbly, cheap Chinese junk and completely unusable. See my previous post.
> _________________
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