[Amps] Hipersil the myth and the truth (Thread)

[Gary Komassa]

Dear Ham Friends,
 
I was reading some of what was written about Myth and Truth concerning Hipersil cores.  I worked for Dahl for 35 years.  All our C-Cores were purchased from Westinghouse in the beginning.  That is why he started using the term "Hipersil" .  It was NOT for a selling term however that's what the customers were using with their requests and insisted on that term for the C-Cores.  Yes, I have heard Hipersil material is available in the EI lamination's too.  The problem was if you were to purchase EI Laminations with that more expensive material one would be accused of gouging the public and they would insist they could buy the Transformers elsewhere cheaper.  Remember, you cannot easily look at the physical characteristics of a Transformer and determine what the material is.  We used 4 mil material, 7 mil material, 11 mil material and 12 mil material.  When you looked at his Transformer did you determine which material it was?  The
 Transformers Dahl designed were typically designed for 55 degrees c and I know for a fact he tried his hardest to cram as much copper along with some of the finest and most expensive insulation available between the windings and layers.  Most companies will use copper that will barley accommodate the required amperage and the least expensive kraft paper but Dahl always exceeded that by huge margins.  The only time it was questionable was when the amplifier manufacture made the available space so small nothing would fit with any improvements.  That is why many were offered in "outboard" configurations.
 
The other thing I would offer is look for Dahl Transformers on ebay.  All those with a yellow and white label and colored in amber were MADE IN THE 70'S.  We changed ours to black because a customer buying a half a million dollars a year insisted they wanted black as it looked much better in their Broadcast Radio Transmitters then the amber color.  It has nothing to do with heat dissipation.  Strictly cosmetic.  It became standard as we only had one dip tank.
 
I will answer any other questions you may have if I can as I did all the Purchasing, 95% of the sales, the payables and put out all the "fires" and wound, tested, baked, and shipped them for the first 13 years.  Was in the office the rest.
 
The last thing I will add is the "serial number" is the date of manufacture so if you purchase one and the person says it is new you can tell if he is honest.  We did not date the amber colored units.
 
Please go to this web site and read carefully: 
 http://www.tech-systems-labs.com/books/hipersil.pdf
 
This book in the above web site  is the main one Dahl used to form his designs.  I am not an EE but spent a lot of time with Transformers.  
 
Thank you,
 
Gary