Hi, I have been using this combination and got some good reports but I have not a reasonable idea of power output. So I would like to have a good estimation from those who are better prepared to do it.
Thanks^6 73 de Jose' CT1AXG Date: Fri, 17 Mar 2006 22:03:50 -0500 From: "kenw2dtc" <[EMAIL PROTECTED]> Subject: Re: [AMRadio] Amplifier to use with my DX-60 To: "Discussion of AM Radio" <[email protected]> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; format=flowed; charset="windows-1250"; reply-type=response Don K4KYV said: "I hear a lot of guys on the air with AM linears, and most of the time they claim to be running way too much carrier for the tubes they are using. I often hear stuff like 200 watts out with a pair of 811A's or 250 watts out with a pair of 813's in g-g. If so, they are cooking the tubes, or else the efficiency is running too high, and they are flat-topping all over the place." I agree with your comments and yes, there is no doubt that those rigs are flat-topping. I've been running linear amps on AM for years and I find that the cleanest, best sounding signal comes from a linear with LOTS OF PLATE DISSIPATION and HEADROOM. In addition, an audio signal generator and an oscilloscope are mandatory to get clean results. Not everyone has this equipment and it is a hobby after all so folks do the best they can. As a rule of thumb I consider the plate dissipation divided by 3 to be a general yardstick for AM linears, some tubes giving a little more and some a little less. In the case of a pair of 3-500Z's I rate them in the 333-350 watt carrier class. So while a pair of 813's can be a wonderful plate modulated rig, as an AM linear they are not worth all the trouble of building them. It seems to me to be a waste of time to build an AM linear with much less than 1000 watts of plate dissipation. Of course if you have a low power rice box and already own some kind of linear, well go ahead, but if one is building an AM linear, more dissipation is better. 73, Ken W2DTC __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
