The Audio Transformer Design & Construction Series has been very popular. The DVD's in the ATD&C Series provide information that is nearly impossible to find elsewhere and this latest addition is no exception. Unlike the two previous volumes of this series there are no obscure, out-of-print books, articles or transformer core catalogs in this third volume. Volume 3 contains three different transformer dissection papers in .pdf, picking up where the Peerless K-241-D/4665 paper, which is on volume 2, left off.     The response to the Peerless paper was overwhelmingly positive and requests for more dissections started rolling in. So in Volume 3, three more complete and very detailed vintage audio transformer dissections are presented right down to the coilform.

 Volume 3 has detailed dissections of the sadly discontinued vintage Triad HS-52 Vacuum Tube Output Transformer, a Western Electric 111C Line Level Matching Transformer, and, for the first time ever, three Neumann BV style Transformers. The BV-8 (early red  bobbin and late clear bobbin), both used in the Neumann U-47 Microphone, &  the BV-11 which was used in the Neumann M49 M50 Microphones. These particular transformers were chosen because they represent three very different transformer topographies yet all are noted for the sonic quality.

Every original manufacturer's winding detail is shown as each unit is completely disassembled. Dozens and dozens of scans and photos, all stored in the .pdfs in high resolution and are extractable for hi-res magnified viewing. These papers were almost of year of work in the making. Note: These are large .pdfs, because of the large hi-res photos, but being able to see the details is where the knowledge is.

This disk is available at a large discount when
Purchased along with volume 1 &2 as a set !

Here are the papers that are included:

Rewinding the Triad HS-52 Vacuum Tube Output Transformer
 by C. H. Preston c2011. Every detail you ever wanted to know about winding and rewinding these excellent, shell style, sadly discontinued, preamp output transformers. There are dozens of photos, scans and diagrams along with page after page of information. HS-52's have recently sold on e-bay for $500 !!! Rewind or remake, there is no magic in them. They can easily be built today and even improved! See all the details here.

Here is the second paper:

Inside German Vacuum Tube Microphone Transformers
by C. H. Preston c2011. This is the real deal. Information you can't find anywhere!! This file has the complete dissection of three different BV-8 & BV-11 vacuum tube microphone output transformers (used in the Telefunken/Neumann U-47, M49, M50 microphones). Every detail !! All photos are in high resolution and extractable. All winding details are clearly shown. The BV style of transformer is a winding style that can be scaled and applied to other audio applications. They are very high quality, semi toroidal, fully humbucking, output transformers. This paper has some great engineering tips as well as refuting some other inaccurate web information.

Here is the third paper:

Engineering the Western Electric 111C Line Level Matching Transformer
by C. H. Preston c 2011. These transformers are absolutely fascinating inside. They show some of the best transformer engineering practices ever employed. The 111C was a massive toroidal line level transformer that was in production and used in industry for over 50 years. While recreating this exact transformer today might be more expensive than the market would support, the lessons learned in the engineering of these incredible transformers are priceless. This paper was a lot of work to assemble but it was one of the most rewarding educational experiences I've had. They don't make 'em like this anymore !  Excellent Western Electric, Bell Laboratories toroid winding practices are revealed.

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