[sdiy] passive ring modulator transformers

[Tom Arnold]

On Sat, Jan 16, 2016 at 05:26:11PM -0500, alfred.pear at gmail.com wrote:
>    hello SDIYers,
>    i'm currently trying to figure out how to get reasonably affordable
>    transformers for a passive ring modulator.

Kevin Lightner had an old passive ring modulator schematic from the 60s on
his site.  I can't find my copy of it, but it called for germanium diodes and
a Stancor A-4713 tranformer.  I contacted Stancor and they sent me the catalog
page.

10k primary impedance with a 2:1 Primary to one-half secondary ratio.  Frequency
response listed as 100-20000hz +-3db.

Based on that, the cheapest readily available transformer was the Xicon
42TM018 available from Mouser for $3.55.  On the specs its lacking in response
but I have made quite a few of them and they sound great for the cost.  I did
spent the time to match germanium diodes at first, but they are such
tempermental buggers I gave up that practice for new stock
hopefully-same-batch diodes. ( hint : wear gloves, use insulated tip needle
nose pliers to move the diodes around, and a full face shield so you don't
breath on them, and test quickly before the temperature changes in your work
area.  Or just skip all that and it'll still sound fine... )

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -  "...is it a virus, a drug, or a religion?"
 - K6AET            -  Juanita Shrugs. "What's the difference? 
 --------------------         -- Neal Stephenson,  Snow Crash