Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-me04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3A7C4380000A6; Mon, 10 Sep 2012 08:12:32 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TB2pa-0002ys-SV for rs_out_1@blacksheep.org; Mon, 10 Sep 2012 13:11:10 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TB2pa-0002yj-FC for rsgb_lf_group@blacksheep.org; Mon, 10 Sep 2012 13:11:10 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1TB2pY-0003tL-RD for rsgb_lf_group@blacksheep.org; Mon, 10 Sep 2012 13:11:09 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id q8ACB7xC020107 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 10 Sep 2012 14:11:07 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q8ACB7qF016769 for ; Mon, 10 Sep 2012 14:11:07 +0200 Message-ID: <504DD81C.3000109@iup.uni-heidelberg.de> Date: Mon, 10 Sep 2012 14:07:56 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4lxai1mwypydokybe3cdcara.1347264326145@email.android.com> In-Reply-To: <4lxai1mwypydokybe3cdcara.1347264326145@email.android.com> X-Spam-Score: -2.7 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Christian, Am 10.09.2012 10:05, schrieb C. Groeger: > Hi Stefan! > I don't know the problem yet. Maybe these small fets went to hot. > My pa design is very simple, 2 x irf 540 parallel in class D, transformer to 50 ohm, Pi filter and variometer. > Operating voltage was 12 V only but nevertheless resulting an Input of 120 watts. > The advantage of a homemade PA is that you normally use cheap and easy available parts which are easily replaceable. The IRF540 costs about 0.6 Euro so that's all not so dramatic at least. [...] Content analysis details: (-2.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [129.206.210.211 listed in list.dnswl.org] -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: e09cca6d8e44a91eadbdfb3e1b8aec09 Subject: Re: LF: MF PA Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1d608c504dd93050cf X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hello Christian, Am 10.09.2012 10:05, schrieb C. Groeger: > Hi Stefan! > I don't know the problem yet. Maybe these small fets went to hot. > My pa design is very simple, 2 x irf 540 parallel in class D, transformer to 50 ohm, Pi filter and variometer. > Operating voltage was 12 V only but nevertheless resulting an Input of 120 watts. > The advantage of a homemade PA is that you normally use cheap and easy available parts which are easily replaceable. The IRF540 costs about 0.6 Euro so that's all not so dramatic at least. OK, 120W input power at 12V DC in class D mode. But what was the output power? Class D, so it is hard switching with a rectangular gate voltage, cfm? What is the driver you're using to drive the FETs? If the driver is strong enough to provide good switching times even at high input Cs then maybe a IRFZ48N or better an IRFP064N may be a better choice at 12 V DC. They are all cheap and available at Reichelt, you know... Here, i'm using this PA design: https://dl.dropbox.com/u/19882028/MF/100W%20475kHz%20PA.png and https://dl.dropbox.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.JPG 73, Stefan/DK7FC