[BC] 111C Repeat coils and Jensen replacements

[Mike McCarthy]

It will be a suitable replacement if the beast can handle +5dBm at 20Hz 
with less than 5% THD.

Nothing I have seen to date past the 111C will give me +5dBm at 20hz with 
less than 5% THD (saturation point.)  Keep in mind, the "100%" point for 
ma-bell was 0dBm.  So that 5dB was gravy.  If you band limit the low end, 
40Hz was something like +10 and 50hz was +15.

MM

At 06:47 PM 4/8/2007 -0500, seaberg1 at sbcglobal.net wrote
>Russ and all the other transformer intelligentia on this list.
>
>I have in my hands an assembly containing two HAMMOND
>(made in Canada) transformers which show an apparent model
>number MRI 3002.  I was told by a very respected engineer that
>they were an equal or better substitute for the WE-111 transformer.
>They certainly are smaller in physical size.
>Your comments please.
>
>Bob Seaberg -- W3MDM
>
>----- Original Message ----- From: <RLO2L at aol.com>
>To: <broadcast at radiolists.net>
>Sent: Saturday, April 07, 2007 2:07 PM
>Subject: [BC] 111C Repeat coils and Jensen replacements
>
>
>>
>>Gentlepeople:
>>
>>I am passing along a response to some of the comments about the 111C repeat
>>coils from my good friend Bill Whitlock who now runs Jensen transformers.
>>
>>
>>Hi Russ,
>>
>>Jensen makes the following standard  (deliverable off-the-shelf) designs that
>>are functional equivalents of the  Western Electric 111C "repeat coils". All
>>have multiple internal Faraday  shielding, external magnetic shielding cans,
>>-3 dB bandwidth extending from well  under 1 Hz to at least 200 kHz, and
>>extremely low harmonic distortion. The three  models vary in package and 
>>level
>>handling ability - remember that level-handling  for a transformer must 
>>specify
>>frequency and that, for the same THD, level  handling always decreases with
>>frequency. The single-piece, end-user prices  are $133, $137, and $196, 
>>respectiv
>>ely. OEM and quantity pricing (which begins  at quantity 4) are considerably
>>lower. These "repeat coil" designs, which  combine the properties of input
>>transformers (Faraday shielding) and output  transformers (ability to 
>>drive long
>>cables/capacitive loads) are widely  used for patchbay applications. The
>>following are links to our data sheets.
>>_http://www.jensentransformers.com/datashts/11ssp6m.pdf_ 
>>(http://www.jensentransformers.com/datashts/11ssp6m.pdf)
>>_http://www.jensentransformers.com/datashts/11ssp7mp.pdf_
>>(http://www.jensentransformers.com/datashts/11ssp7mp.pdf)
>>_http://www.jensentransformers.com/datashts/11ssp8ma.pdf_
>>(http://www.jensentransformers.com/datashts/11ssp8ma.pdf)
>>Numerous application notes and quantity  pricing are also available at our
>>website.  Don't hesitate to contact me with technical questions.
>>
>>[Russ, feel free to post this on the list if  you like - and thanks for
>>passing on the post. Happy holidays!]
>>
>>Cordially,
>>Bill Whitlock,  president & chief engineer
>>Jensen Transformers,  Inc.
>>(from my home  office)
>>
>>Best,
>>
>>
>>
>>
>>Russel L.  O'Toole, P.C.
>>R&M Consulting
>>
>>31 Ponderosa  Drive
>>Romeoville, Illinois 60446
>>815-372-1990 voice
>>630-699-2965  cell
>>815-886-9232 fax
>>KD5OAE General