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<p>Excellent. Thanks. I have the older Handbook. Time for me to
upgrade the bible (the book).</p>
<p><br>
</p>
<p>Take care,</p>
<p><br>
</p>
<p>Bob</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 1/30/22 12:18 PM, Bill Whitlock via
ProAudio wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1183025994.2982633.1643563100736@mail.yahoo.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div style="color:black;font: 12pt Arial, Helvetica, sans-serif;">Yes,
increasing series R on the drive side will exaggerate magnetic
non-linearities of the core material (i.e., THD). If you want
to shift the mix of odd to even order harmonics, add a few mA of
DC on the primary side (say 0 to 30 VDC through a 10 k-ohm
resistor directly to the primary side.
<div><br>
</div>
<div>The R and C (in parallel) across the secondary will control
the frequency and Q of the self-resonance.</div>
<div><br>
</div>
<div>You can read my "Audio Transformers" chapter in the Ballou
"Handbook for Sound Engineers" for more details.</div>
<div><br>
</div>
<div>Bill<br>
<br>
<br>
<div
style="font-family:arial,helvetica;font-size:10pt;color:black"><font
size="2">-----Original Message-----<br>
From: Bob Katz via ProAudio <a class="moz-txt-link-rfc2396E" href="mailto:proaudio@bach.pgm.com"><proaudio@bach.pgm.com></a><br>
To: <a class="moz-txt-link-abbreviated" href="mailto:proaudio@bach.pgm.com">proaudio@bach.pgm.com</a><br>
Sent: Sun, Jan 30, 2022 8:39 am<br>
Subject: Re: [ProAudio] Western Electric 111C transformers<br>
<br>
<div id="yiv2030202385">
<div>
<div>Now we're cooking!</div>
<div>Dear Bill: Thanks. <br clear="none">
</div>
<div>Yes, I am looking for color. I understand the
series resistor. I'll probably use a dialpot so I
can log the setting for recall.</div>
<div>On the secondary side, are you suggesting a
variable load R with the C across it? <br
clear="none">
</div>
<div>If I am looking for color and want to do some
measurements to see the effect of various source and
load devices, clearly a square wave investigation
will tell me something. Frequency response will tell
me something. What about harmonic distortion...
probably look at THD at low frequencies???</div>
<div><br clear="none">
</div>
<div>Best,</div>
<div><br clear="none">
</div>
<div><br clear="none">
</div>
<div>Bob</div>
<div><br clear="none">
</div>
<div><br clear="none">
</div>
<div><br clear="none">
</div>
<div><br clear="none">
</div>
<div id="yiv2030202385yqt39568"
class="yiv2030202385yqt9932338404">
<div class="yiv2030202385moz-cite-prefix">On 1/29/22
5:15 PM, Bill Whitlock via ProAudio wrote:<br
clear="none">
</div>
<blockquote type="cite"> </blockquote>
</div>
</div>
<div id="yiv2030202385yqt65427"
class="yiv2030202385yqt9932338404">
<div>
<div style="color:black;font:12pt Arial, Helvetica,
sans-serif;">If you're after coloration, the
strongest influencer of distortion is source
impedance, so I'd put something like a 1 or 2
k-ohm pot (connected as a rheostat or variable
resistor) in series with the primary high side
terminal. At high-resistance settings, you'll'
get some level loss - and possible high-frequency
loss if there's much capacitive load (or cable) on
the secondary side. Putting a variable load
resistance on the secondary, along with some
intentional capacitive load to bring resonance
down toward 20 kHz) will allow control of the
resonance's Q. I don't recall off-hand where the
natural self-resonance of the secondary is, but
I'd start with 1 nF or so and use a 50 k-ohm pot
(with a series 1 or 2 k resistor to keep
resistance from going to zero) variable load
resistor. Results will, of course, guide you
from there!
<div><br clear="none">
</div>
<div>Bill Whitlock</div>
<div>AES Life Fellow</div>
<div>Whitlock Consulting</div>
<div>Ventura, CA<br clear="none">
<br clear="none">
<br clear="none">
<div style="font-family:arial,
helvetica;font-size:10pt;color:black;"><font
size="2">-----Original Message-----<br
clear="none">
From: Bob Katz via ProAudio <a
rel="nofollow noopener noreferrer"
shape="rect"
ymailto="mailto:proaudio@bach.pgm.com"
target="_blank"
href="mailto:proaudio@bach.pgm.com"
class="yiv2030202385moz-txt-link-rfc2396E"
moz-do-not-send="true"><proaudio@bach.pgm.com></a><br
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To: <a rel="nofollow noopener noreferrer"
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ymailto="mailto:proaudio@bach.pgm.com"
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clear="none">
Sent: Sat, Jan 29, 2022 1:16 pm<br
clear="none">
Subject: [ProAudio] Western Electric 111C
transformers<br clear="none">
<br clear="none">
</font>
<div id="yiv2030202385">
<div>
<pre class="yiv2030202385moz-quote-pre">Hola, Guys. I’ve got a pair of these sitting around doing nothing. I’m sure their effect will be subtle but it might be nice to package them into a passive box for their color in a mastering session.
To vary their color would you have any suggestions on switchable buildout or termination resistors or zoebel networks I might want to add to the box, in addition to hard wire bypass?
Appreciate any suggestions. Thanks
Bob</pre>
<div class="yiv2030202385moz-signature">--
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If you want good sound on your album, come to
Bob Katz 407-831-0233 DIGITAL DOMAIN MASTERING STUDIO
Author: <b>Mastering Audio</b>
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If you want good sound on your album, come to
Bob Katz 407-831-0233 DIGITAL DOMAIN MASTERING STUDIO
Author: <b>Mastering Audio</b>
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