Come to think of it - since it is a grounded grid amp, some of the driver power is appearing in the output, so actual efficiency is really a bit below 68%. Still quite good. The output AM carrier power ratio holds; for faithful reproduction of AM with 100% positive modulation, the carrier power will be 357.5 watts.
----- Original Message ----- From: "Bob Bruhns" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" <amradio@mailman.qth.net> Sent: Friday, January 14, 2005 11:51 AM Subject: Re: [AMRadio] AM Amps > Nice amp! 670 watts dissipation, 1430 watts out means 1430 + 670 > watts input, or 2100W input. (This agrees with the plate voltage > and plate current.) Efficiency would be 1430/2100 = 0.681 or 68.1%, > which is quite good for a linear amplifier at maximum output. > > In linear operation, an amplifier's efficiency is proportional to > its output. At full power output, you get maximum efficiency. That > means 1430 watts is the maximum output for the particular tuning > adjustment of the amp. So an AM signal passed through this > amplifier set up as described would produce positive peaks up to > 1430 watts. For faithful reproduction of AM with 100% positive > modulation, this would correspond to 1430/4 = 357.5 watts carrier. > So somehow the driver power would have to be reduced for proper AM > operation. Your mileage may vary. > > > ----- Original Message ----- > From: "James M. Walker" <[EMAIL PROTECTED]> > To: "Discussion of AM Radio" <amradio@mailman.qth.net> > Sent: Thursday, January 13, 2005 11:48 AM > Subject: Re: [AMRadio] AM Amps > > > > Hum, > > 4-1000A G.G. amplifier, 3000 VDC plate, 700 MA Plate I, 500 MA > > Grid I, with 125 Watts out of DX-100 running apprx 2100 W input > and > > dissipating 670 watts plate = approximately 1430 watts output! > > > > While the carrier level into 50 ohm dummy load is 1400 watts > measured > > and a really NICE orange glow! This is with a 200 cfm blower, air > system > > socket and chimney. > > > > Jim > > WB2FCN > > > > ----- Original Message ----- > > From: "Jim candela" <[EMAIL PROTECTED]> > > To: "Discussion of AM Radio" <amradio@mailman.qth.net> > > Sent: Wednesday, January 12, 2005 7:07 PM > > Subject: RE: [AMRadio] AM Amps > > > > > > > > > > Darrell, > > > > > > That amp you built with the 4-1000 was a "killer" in more ways > than one! > > > Time for a confession.. > > > > > > Regards, > > > Jim > > > WD5JKO > > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] Behalf Of Darrell, > WA5VGO > > > Sent: Tuesday, January 11, 2005 6:04 PM > > > To: Discussion of AM Radio > > > Subject: Re: [AMRadio] AM Amps > > > > > > > > > At 04:21 PM 1/11/2005 -0500, you wrote: > > > > > > >In a message dated 1/11/05 12:14:43 PM, > [EMAIL PROTECTED] writes: > > > > > > > > > > > > > well all I can say is it works.. works well as a matter of > fact, and > > has > > > > > been for 6 years :) > > > > > I typically run between 350 and 400 watts of carrier every > day. It > > looks > > > > > great on the scope. Modulation envelope is perfect. 100% > modulation. > > In > > > 6 > > > > > years Ive only lost one tube, and I accidently broke that > one. > > > > > > > > > > > > > > > > > >I have to agree with Gary. You're seeing 1600 watts PEP and > 400W of > > > carrier > > > >OUT with a pair of GG 813s??? Does not compute! Just > curious, are you > > > >talking about 400W INPUT power to the linear under carrier only > condx > > > >maybe? If > > > >so, this would work out to about 133W carrier OUT and each 813 > > dissipating > > > >about 133W which would make more sense. > > > > > > > >Dennis D. W7QHO > > > >Glendale, CA > > > > > > > > > I'm with Dennis and Gary. To run a linear amplifier at 375 watts > of > > carrier > > > and 100% modulation, you will need around 800 watts of plate > dissipation. > > > For a short time a number of years ago, I tried running an AF-68 > and a > > > 4-1000A linear amplifier. I could never get more than around 450 > watts of > > > carrier and stay linear............I didn't need a heater in the > shack > > > either. > > > > > > 73, > > > Darrell, WA5VGO > > > > > > > > > > > > 73, > > > Darrell, WA5VGO > > > > > > > > > > > > > > > ______________________________________________________________ > > > AMRadio mailing list > > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > > Help: http://mailman.qth.net/mmfaq.html > > > Post: mailto:AMRadio@mailman.qth.net > > > > > > -- > > > No virus found in this incoming message. > > > Checked by AVG Anti-Virus. > > > Version: 7.0.300 / Virus Database: 265.6.10 - Release Date: > 1/10/2005 > > > > > > -- > > > No virus found in this outgoing message. > > > Checked by AVG Anti-Virus. > > > Version: 7.0.300 / Virus Database: 265.6.11 - Release Date: > 1/12/2005 > > > > > > ______________________________________________________________ > > > AMRadio mailing list > > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > > Help: http://mailman.qth.net/mmfaq.html > > > Post: mailto:AMRadio@mailman.qth.net > > > > > > > > > > ______________________________________________________________ > > AMRadio mailing list > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > > > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net >
