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Title: Viking I as a Class C & Class B driver Post by: Steve W8TOW on September 27, 2012, 08:43:26 PM Hey gang, looking at the schematic of a Viking I, I see the mod iron does
not have a 500 ohm tap. I'd like to use this rig to drive one of my HB tx, a Pair of Taylor T-200's modulated by Taylor 203Z's. The grid input of the 203Z's is connected of a nice UTC driver iron with 500 ohm inputs.... Some thoughts are to: 1. Install a new mod iron on the Viking I like a UTC CVM2 or CVM 3 which has 500 ohm output taps 2. Install a mod iron from a Valiant which has 500 ohm output taps 3. Find a different mod iron that will work with 807's like one from a 32V or similar... Will the Z match of the Valiant mod iron match 807's? since it was designed for 6146's??? 73 Steve Title: Re: Viking I as a Class C & Class B driver Post by: w4bfs on October 03, 2012, 10:29:22 AM Hi Steve ... since the 807 and 6146 were developed from the 6l6 it stands to reason that they would have similar output load Z ... I'm not familiar with drive req'mts for 203 .... the Valiant iron at half power should do fine since there would be no secondary dc load
INCIDENTALY ...shouldn't this thread be in the technical forum section ? 73 John Title: Re: Viking I as a Class C & Class B driver Post by: Opcom on October 03, 2012, 08:28:54 PM Look at the Viking I. Under the chassis, you should see four modulation secondary wires. The 500 Ohm windings are in series for the Viking and 4D32 (600V/300mA=2K), but for driver use they should be put in parallel for 500 Ohms line. The book or an appnote says something about it. Mine had this, others ought to.
Title: Re: Viking I as a Class C & Class B driver Post by: Steve W8TOW on October 05, 2012, 10:08:23 AM Great! Thanks, I just got under the Viking I this morning and YES! There
are 4 sets of wires... Many thanks...I am good to go... BTW, a pair of 6L6's drives the 203Z quite well. Once with a 32V as a RF Exciter and AF Driver, I had no prob with the 807's of the 32V... 73 Steve 8tow Title: Re: Viking I as a Class C & Class B driver Post by: W2VW on October 05, 2012, 12:17:26 PM Consider adding inverse feedback to the driver stage. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Probably time to brush up on drive requirements for class B audio power amplifiers. The Orr books have plenty of info to help keep your signal healthy. |