Custom Transformers & Inductors



Latest News & History

August 2020:

More R.L. Drake receiver information.  We are now shipping power transformers for the R-4, R-4A, R-4B receivers - T15 transformer (PWDP13202). We also just finished the design for the R-1A power transformer, see our "Amateur Radio Products" section for full details.

February 2020:

Long live the Johnson Viking Ranger.  We have now finished designs on all magnetics for this popular transmitter. T1 Power (PWDP13183), T2 Modulation (PWDM13007), T3 Audio Interstage (PWDA13076) transformers and the filter choke (PWDI13014) are now available!

January 2020:

Direct replacement power transformers (T14) are now available for the Drake receiver R-4C - Hammond Part Number PWDP13178.

January must be Drake month - we are just finishing up a design for the direct replacement of the power transformer used in the Drake AC-4 power supply. Used with all the Drake "4" line transmitters and transceivers T-4X, T-4XB, T-4XC, TR-4, TR-4B, TR-4C etc. Hammond Part Number PWDP13137

May 2019:

Both filter chokes are now available from stock - used in many Collins receivers. Most notably the 75A series of receivers. The 3 Henry (120 ma.) choke - Collins part number 668-0020-00 (L29 in the photo below) Hammond Part Number PWDI13161 and the 5 Henry (80 ma.) choke - Collins part number 668-0019-00 (L30 in the photo below) Hammond Part Number PWDI13158.

March 2019:

Currently finalizing designs on two new filter chokes used in Collins receivers. Most notably the 75A series of receivers. The 3 Henry (120 ma.) choke - Collins part number 668-0020-00 (L29 in the photo above) and the 5 Henry (80 ma.) choke - Collins part number 668-0019-00 (L30 in the photo above).

May 2015:

Click here to enlarge

Mike (K4VJ) - our Beta tester of the PWDP13049 (Alpha TPX-X168) has confirmed installation & use (see photo above). Thanks again Mike! Therefore - we have released a stock order to our production department. We are now accepting orders for this part.

April 2015:

More news for ALPHA 91b & ALPHA 99 amplifier owners. We are now in final design & production of the replacement TPX-X168 power transformer (extra THANKS to Mike - K4VJ for all his help). We will be shipping & stocking part number PWDP13049 transformers this month. We appreciate everyone's patience while we verify all the final design details.

Our PWDP13049 "first off" shipped today - April 29. This unit is a direct replacement for the ALPHA 91b & ALPHA 99 power transformer (TPX-X168). After final confirmation - we will begin producing stock units.

February 2015:

Great news for Heathkit SB-220 owners. We are now manufacturing & stocking both the direct replacement power transformer (part number PWDP13034) & the heavy duty Hipersil unit. Thanks to Dennis (N9AD) for beta testing & confirming installation of our heavy duty unit (part number PWDP13026) power transformer. It is almost double the capacity of the original unit. Easy installation requiring only a small cutout in the top internal perforated cover See photos also compliments of Dennis (N9AD).

December 2014:

Great news for ALPHA 91b & ALPHA 99 amplifier owners. We will be manufacturing & stocking part number PWDP13049 power transformers. This will be a "plug & play" replacement power transformer. Thanks to Glenn (AE0Q) at RF Concepts for digging into the ALPHA AMPLIFIERS archives and providing us with all the plug & pin-out data!

July 2014:

Peter W. Dahl transformers - on display. See us at the HAMMOND MFG. booth (#118) at the ARRL National Centennial Convention in Hartford, CT. July 18-19 (Connecticut Convention Center).

March 2014:

Popular Peter Dahl designs are now shipping from our stock. We are constantly adding more parts to our inventory for faster turnaround. We are also now stocking the most popular "C-Cores" in our raw material inventory for quick turnaround on designs we do not carry in stock. The "C-Cores" have become the most expensive item of the Hipersil designs over the past years and the longest lead time item.

November 2013:

Thanks for everyone’s patience! We are now catching up on past quote requests and continuing to build orders & inventory of stock units. This has certainly turned out to be a “labor of love” for the crew at Hammond Mfg.

October 2013:

Peter W. Dahl designs live YET again! Thanks to Jeff at Harbach Electronics (www.harbachelectronics.com) hundreds of designs are recovered.

September 2013:

Good news - even though the old Peter W. Dahl server is a goner - we were able to get 100% recovery off the removed old SCSI drive. Thanks to Gillware Inc. (www.gillware.com) - highly recommended for data recovery.

Bad News - both the workstation & operating software compiling the transformer designs, spans decades. No longer supported software and/or software companies long out of business make duplicating the original server near impossible.

August 2013:

Unfortunately, we have experienced a "meltdown" with the old Peter W. Dahl network/server which holds the designs. We have a few of the designs either in other formats or in stock BUT - please be patient while our IT department works through this recent issue.

June 2013:

The first Peter W. Dahl designs roll off the Hammond Mfg. production line! Hammond Mfg. begins shipping and stocking PWD series units. More to follow on this site as orders are filled and the more popular designs are brought into stock.

Amateur Radio Products web catalog & Commercial Products listing is added to the site.

April 2013:

Hammond Mfg. begins quoting and building transformer designs from Peter W. Dahl's original files. Peter W. Dahl's designs LIVE - once again! Upwards of 5,000 complete designs are available. Original information - spanning decades - exists on almost every part:

  • Drawings and/or dimensions
  • Specifications
  • Detailed Bill of Materials (B.O.M.)
  • Winding & lead data
  • Test data

March 29, 2013:

Finalization of the acquisition and transfer of assets took place and was moved from Polk, Ohio to Hammond Mfg. Co. - Cheektowaga, NY

22 February 2013:

A purchase agreement was signed and executed with Hammond Manufacturing Company, Inc. of Cheektowaga, New York to acquire the Peter Dahl line of products from Harbach Electronics, LLC.

February 2013:

Harbach Electronics, LLC announces discontinuing of the Peter W. Dahl Co. line of transformers - effective February 14, 2013.

August 15, 2011

Peter W. Dahl (K0BIT) passed away peacefully at 71 after a lengthy battle with Parkinson's disease.

February, 2008:

Jeff Weinberg (W8CQ) announces that Harbach Electronics, LLC will be selling Peter W. Dahl designed transformers. Peter W. Dahl designs LIVE again! Harbach Electronics continues to service customers over the next five years.

December 2007:

Peter W. Dahl retires and shutters the Peter W. Dahl Co. in El Paso, Texas. Unable to locate a buyer for the company, the building & land are sold off to a local company. Other assets are also sold to Harbach Electronics, LLC and moved to Polk, Ohio in early 2008.


The land and 17,000 square foot building (located at 5869 Waycross Ave., El Paso, TX) is purchased by Peter & his wife.

May 2, 1977:

The Peter W. Dahl Co. is incorporated in the state of Texas.


The company moves to El Paso in 1966.


The Peter W. Dahl company is started as a sole proprietorship in Minneapolis.

March 13, 1940:

Peter W. Dahl is born in Minneapolis, Minnesota


The O.S. Hammond & Son company (started in 1917) incorporates as HAMMOND MANUFACTURING COMPANY. Exiting the radio building business and focusing on radio components - transformers become one of the main products for the company.


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