Craig,
The Collins folks will cringe at the thought of "hacking up" a 32V2/3. I prefer to "hack up" Johnson gear. I did something similar to Steve on a Viking I. I used a higher power multi-tap modulation transformer (Stancor 120 watt unit) as a choke, picking the taps for the greatest inductance. I then used a hi-fi tube audio output transformer from a Harmon Kardon Citation V amplifier. This iron was rated at 40 watts down to 7 hz, so I figured it would handle lots more at 100 hz and above. I used a 600 watt Crown (M600) amplifier to drive things. One problem with my approach was that my voice was asymmetric, and the big Crown was DC coupled. This resulted in a high amount of DC current flowing in the transformer primary (8 ohm tap to common), and saturation was evident. The fix was to AC couple the Crown to the transformer. I used two 10,000 Uf 100 VDC capacitors in series with the + sides together to in effect make a poor mans non polarized capacitor valued at 10,000 uf (not 5000). These big caps are a near short when reverse biased, so the series cap equation does not apply. Thereafter it worked like a hose...even at 200% positive peak modulation! Regards, Jim WD5JKO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Craig Roberts Sent: Sunday, January 22, 2006 11:28 AM To: Discussion of AM Radio; [EMAIL PROTECTED] Subject: [AMRadio] surrogate modualtor for the 32V Many thans for your reply, John. I've noted from the published specs that the driver and modulation transformers in the 32V-2 are rather restricted in audio bandwidth, too. Perhaps Steve Ickes' approach is worth exploring: http://www.amwindow.org/tech/htm/obmod.htm I have a very nice Ashly preamp/EQ/compressor/limiter and 120 Watt audio power amp that might work very well as a surrogate speech amp/modulator. Has anyone tried Steve's scheme? VY 73, Craig W3CRR ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 267.14.21/236 - Release Date: 1/20/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 267.14.21/236 - Release Date: 1/20/2006
