-----Original Message----- From: [EMAIL PROTECTED] [mailto:amradio-
Glad to hear someone is still flogging those old CE's. I was always partial to phasing rigs and would love to find a 100V again. Carl KM1H Reply by Jim, WD5JKO: Carl, Yes I have been flogging the 20a's for about 5 years now... In fact I was on last night on 3890 LSB running legal limit SSB. The same setup can run about 300 watts AM. The tube lineup was: 1626 Osc 1625 Buffer 6MU8 9 Mc Osc and audio driver 6BA7 Mixer 1/2 12BH7 Driver 2 x 7591 Linear output tubes 8877 Dentron MLA-2500 substitute tube for a pair of dead 8875's Part of my QRO 20a campaign has been to settle down the stock 20A heat issue. Here is an excerpt of my report: The unregulated voltages +550, +290 are both from choke input circuits, so the regulation with these is decent. The Key up high B+ only rises to about 600 volts. Funny thing here is that with choke input filtering, the power transformer runs cooler than a stock 20A, which uses a capacitor input filter circuit. Lowering the B+ on the low level stages also cuts way back on the heat produced. Recall that a stock 20A will run the low level stuff at ~ 400 volts B+ (idle) with today's 120V + line voltages. QRO 7591 output tubes: http://pages.prodigy.net/jcandela/Central%20Electronics%2020a%20QRO%20%2 32/ QRO single E34L output tube: http://pages.prodigy.net/jcandela/CE20AQRO/ 73, Jim JKO ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
