[ProAudio] Western Electric 111C transformers

[Bob Katz]

Excellent. Thanks. I have the older Handbook. Time for me to upgrade the 
bible (the book).


Take care,


Bob


On 1/30/22 12:18 PM, Bill Whitlock via ProAudio wrote:
> 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.
>
> The R and C (in parallel) across the secondary will control the 
> frequency and Q of the self-resonance.
>
> You can read my "Audio Transformers" chapter in the Ballou "Handbook 
> for Sound Engineers" for more details.
>
> Bill
>
>
> -----Original Message-----
> From: Bob Katz via ProAudio <proaudio at bach.pgm.com>
> To: proaudio at bach.pgm.com
> Sent: Sun, Jan 30, 2022 8:39 am
> Subject: Re: [ProAudio] Western Electric 111C transformers
>
> Now we're cooking!
> Dear Bill: Thanks.
> 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.
> On the secondary side, are you suggesting a variable load R with the C 
> across it?
> 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???
>
> Best,
>
>
> Bob
>
>
>
>
> On 1/29/22 5:15 PM, Bill Whitlock via ProAudio wrote:
> 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!
>
> Bill Whitlock
> AES Life Fellow
> Whitlock Consulting
> Ventura, CA
>
>
> -----Original Message-----
> From: Bob Katz via ProAudio <proaudio at bach.pgm.com> 
> <mailto:proaudio at bach.pgm.com>
> To: proaudio at bach.pgm.com <mailto:proaudio at bach.pgm.com>
> Sent: Sat, Jan 29, 2022 1:16 pm
> Subject: [ProAudio] Western Electric 111C transformers
>
> 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
> -- 
> If you want good sound on your album, come to Bob Katz 407-831-0233 
> DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital 
> Domain Website <https://www.digido.com/> No trees were killed in the 
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> -- 
> If you want good sound on your album, come to Bob Katz 407-831-0233 
> DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital 
> Domain Website <https://www.digido.com/> No trees were killed in the 
> sending of this message. However a large number of electrons were 
> terribly inconvenienced.
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-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital Domain 
Website <https://www.digido.com/> No trees were killed in the sending of 
this message. However a large number of electrons were terribly 
inconvenienced.
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