Return-Path: X-Spam-DCC: paranoid 1480; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id uARAW66U001742 for ; Sun, 27 Nov 2016 11:32:06 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cAwhc-0007vK-Gp for rs_out_1@blacksheep.org; Sun, 27 Nov 2016 10:28:56 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cAwhc-0007vB-6I for rsgb_lf_group@blacksheep.org; Sun, 27 Nov 2016 10:28:56 +0000 Received: from mail-wm0-x232.google.com ([2a00:1450:400c:c09::232]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1cAwhZ-00043G-Fe for rsgb_lf_group@blacksheep.org; Sun, 27 Nov 2016 10:28:55 +0000 Received: by mail-wm0-x232.google.com with SMTP id t79so128509685wmt.0 for ; Sun, 27 Nov 2016 02:28:53 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=NF3EhUBzAJHmqIZmiNKbNOeoXF9TUVXdBh1m/f90ogg=; b=zfNgKTwwT+HgOSlFpxQaWQE3fi94lLyuLDvnO3Un1W3k3Jtr62z4zRlWPiTh6NFzK7 50o50iahpyDbzY4t1XF0RCcoQlC3txA6ORI3f+UHxBYzwPOvnXNDnb/YcQIBJ6uIle/Z sFL/cupsni9zC2pmqBTCN+R4FV0U17JSoGrnMi1KiFyy0eFe4j9xAN5RSMnRGnxM2r3g bfJfjrdzy7FmC1rot/mWZlv4wFrTbtM048wgcCM+Bydsi1JTNiRw4LLnKvAkIutnIcNe A2Fpd0pgrWoq0YgtV2KYCgwUBaQUVb7vHyTXlvnCuEYQKchMj8l+qSLMB/WXdx5SAagG E6GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=NF3EhUBzAJHmqIZmiNKbNOeoXF9TUVXdBh1m/f90ogg=; b=OqUekXEwCdGGFq0P8GBr74/v11hkMqGWOtGDY9W3n56pZA4It8tDGeqPtXaSb0BOFe cfi71MjcklyN4id958yi3EWAZJr91j0G9O6a4CdHZv349vr0H5uttkjOgbP7REGDHCFW Kr4SwaSjSxZDK1+Xe0oxJZ43oFw0NC541cP+QyQXIfEDHEqcBnCzWUfwweBaC3VhzWzr /MPKl9bss+Bp/U0xV2lOf3eCeJjoR8ZRZbrN6PUFTpO+HeH98pUPj8lwq7llMuaLJAPJ Uv1tlaRmNr+OstT4fZC7r+RPWoB/zWYfFsvFHv8q0M83GoHeAgZ0Hdq4EN23tQ7noUr7 PZJg== X-Gm-Message-State: AKaTC03MIu6pO+z9O/iFFVwaGsN+A0VQh2kXN2N9GpIIm0qa+mCbDd3j9Swdj6khUpOaxw== X-Received: by 10.28.188.87 with SMTP id m84mr13859615wmf.14.1480242532343; Sun, 27 Nov 2016 02:28:52 -0800 (PST) Received: from [192.168.1.101] ([82.98.23.94]) by smtp.gmail.com with ESMTPSA id ef10sm36988859wjd.22.2016.11.27.02.28.51 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 27 Nov 2016 02:28:51 -0800 (PST) Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: John Rabson X-Priority: 3 In-Reply-To: Date: Sun, 27 Nov 2016 11:28:49 +0100 Message-Id: <9FCDDE00-7831-485E-9CAF-D15E3522A7B9@gmail.com> References: <635074543.20161125135600@chriswilson.tv> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.3124) X-Scan-Signature: 7001055fa59a9c23b9831ea6d317a074 Content-Type: text/plain; charset=utf-8 Subject: Re: LF: H Bridge power MOSFET based amps question 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by paranoid.lipkowski.org id uARAW66U001742 Content-Length: 1342 Status: O X-Status: X-Keywords: X-UID: 9574 My experiences with class E single ended amplifiers is similar to that reported by Mal. The only caveat I would add is that you should be quite sure that you have the right driving waveform. During my early experiments with a design based on G3NYK’s spreadsheet I tried a sine wave rather than the square wave it should have had. The result was lower efficiency and a short life for the FET. John F5VLF > On 26 Nov 2016, at 11:35, mal hamilton wrote: > > Chris > The Decca 5501 amp modules use a H bridge class D configuration followed by a series resonant PA circuit and this is probably one of the most reliable amplifiers about. Use suitable rated FET'S to give the desired RF output. > Also the protection cct used avoids disaster in the event of an antenna failure short/open cct, > I have built lots of class D 1Kw push pull amps over the years for LF/MF but they are vunerable to damage with load variations whereas the Decca bridge amps survive. I never had a failure with the Decca, and have been using them for many years. > Another approach which is worth a consideration is the class E amp single ended, these are very reliable and avoids the crossover switching problems with the push pull system. Setting up procedure is critical but there after very stable, > Hope these observations help you