[TowerTalk] New tool - toroidal ferrite core inductor calculator

[Wes]

In 1980 I was traveling a week at a time from Tucson to Conoga Park on business.

Working on some personal project I needed some toroids and I actually visited 
Amidon's garage while I was in the neighborhood, so to speak. He for sure was 
marking up prices, but as Jim Lux says, he was doing a service, selling small 
quantities that manufactures weren't about to sell.

Wes  N7WS


On 6/16/2021 6:23 PM, Lux, Jim wrote:
> On 6/16/21 4:07 PM, Jim Brown wrote:
>> On 6/16/2021 2:39 PM, Dan Maguire wrote:
>>> I never found an actual datasheet for Amidon type 31.  A link to a
>>> page showing the u'/u'' plots, not just physical dimensions, would be
>>> much appreciated.  Amidon has not responded to email requests.
>>
>> Amidon is not a manufacturer, they are a distributor/reseller, and they've 
>> been selling stuff at VERY high markups (like $15 for a part that costs them 
>> less than $3) for years, having invented part numbers like 240-xx. The 
>> manufacturer of the parts identified with Fair-Rite mix numbers is Fair-Rite, 
>> an old line US company. Many manufacturers make mixes similar to their #43 
>> and their #61. The chemical recipes for some of these materials is a closely 
>> guarded secret. The properties of #31 is quite special compared to other MnZn 
>> materials.
>>
>> Many years ago there was a ham named Amidon. Long SK.
>
> Here's what I know...
>
> Bill Amidon, in North Hollywood, literally in his garage (the Otsego st 
> address is in a residential area), bought wholesale and repackaged for ham and 
> entertainment industry use in little envelopes. He published a giant tissue 
> paper datasheet that you unfolded like a map.  A fairly steep markup as I 
> recall, but back then, the mfrs only sold substantial quantities (100s) - I 
> think Palomar Electronics did the same sort of thing.
>
> He sold out quite a while ago, I'm thinking the 80s - The company got into the 
> magnetic recording head business (that may also have been part of Bill 
> Amidon's business) and moved down into the South Bay (Torrance or somewhere 
> like that) to be close to Ampex and similar suppliers. They grew, and then 
> split into the "recording head" and the "ferrite components" businesses - the 
> recording head business long ago collapsed (not just for them).  I honestly 
> don't know why they even still sell in small retail quantities.  Amidon 
> Associates was founded in 1990, and I think that's roughly the time of the 
> split up.