Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_PASS, T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v35CYAAO008840 for ; Wed, 5 Apr 2017 14:34:11 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cvk3d-0007GZ-3O for rs_out_1@blacksheep.org; Wed, 05 Apr 2017 13:29:05 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cvk3b-0007GQ-G0 for rsgb_lf_group@blacksheep.org; Wed, 05 Apr 2017 13:29:03 +0100 Received: from mail-wr0-x234.google.com ([2a00:1450:400c:c0c::234]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1cvk3X-0002uS-MU for rsgb_lf_group@blacksheep.org; Wed, 05 Apr 2017 13:29:02 +0100 Received: by mail-wr0-x234.google.com with SMTP id t20so12447321wra.1 for ; Wed, 05 Apr 2017 05:28:59 -0700 (PDT) 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=20161025; h=from:date:message-id:to:subject:in-reply-to:references:mime-version :content-transfer-encoding; bh=ls619PppCQ/06WmyPZfBpsiNwDM7wejcVunoToeuF24=; b=LeehZVimbl9QFsKfu5rJTBVxOMtMRo5QsC2K/Y4/MMZIteUuJSMbC2PxsyOqq1LByT hjUdWoi7oFgLCk2OvMi/EyNt0ufOJ4/hJueQZMhk2/kZdCvcibK8PqQjdT3XfLZYXUuS Rin+FpZD6OhjsrSrxjNe3GgmTgYmNOKfCqUFL9ZgWTB3hkoUhKVYufk/91m4D+3Ipf76 Qb+NlIdZwDMzo6zybCt+Da2hGTgwltwA8in3XbyYjjXan9A/Ya21ZjJB+8LyBUYVpxwj FHwqqvgSrFMyMUwzielhj+RRZ1fvaRgjh9j7rU7zeOHtRubgY0emJgGsjCjGLPE4pL+2 QzCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:message-id:to:subject:in-reply-to :references:mime-version:content-transfer-encoding; bh=ls619PppCQ/06WmyPZfBpsiNwDM7wejcVunoToeuF24=; b=R+R5F8TyCAsQUua4k7vicp7dtFVMndX/8EfRbP+NFJl1fdYuZ++qvQZe5whG12HuHA 0AKBlfQavvHkxIQnKCCyoPfx78TAjAUmUIQ/ZZ8xH8quiW3tniLgKo643xyuzhRPDw1s 2IJMxqVVXRpJSuF+X1kMiKisyIhEWpI1CDcx7ZKXBFTnbWj1SxNEadMP+rbojOTsJ9bL Dh6HNPBam2dwjiKFzobSGMbsuwY/ZpFh8JX/CTxrZGlOzf2IZ5IeZW/pQpZo/2srdmUU uYy9O6IyvitQ8iGLGVNDNYlBLH5rV349/WcJjpq/XeSwjVLa38YhThFO30QASJmvROc4 lPqw== X-Gm-Message-State: AFeK/H3/m8ts56uYXYucsJ45AU+cJUPQSxiabzLDSbEA0gXj7PV97RQ5DNYK8YS3zDWtvQ== X-Received: by 10.28.149.208 with SMTP id x199mr19400275wmd.91.1491395338224; Wed, 05 Apr 2017 05:28:58 -0700 (PDT) Received: from OfficeWin7.lan (82-70-254-222.dsl.in-addr.zen.co.uk. [82.70.254.222]) by smtp.gmail.com with ESMTPSA id k128sm22170659wmf.16.2017.04.05.05.28.57 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 05 Apr 2017 05:28:57 -0700 (PDT) From: Chris Wilson X-Google-Original-From: Chris Wilson Date: Wed, 5 Apr 2017 13:28:56 +0100 X-Priority: 3 (Normal) Message-ID: <10329669.20170405132856@gmail.com> To: M0FMT In-Reply-To: References: <15b2eda0ec6.marcocadeddu@tin.it> MIME-Version: 1.0 X-Scan-Signature: 4e3b1488273adbbe9757d6bdd5adf219 Subject: Re: FW: LF: FETs getting sick - why not use tubes? Content-Type: text/plain; charset=utf-8 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 2.75 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by lipkowski.org id v35CYAAO008840 Status: O X-Status: X-Keywords: X-UID: 11113 Hello M0FMT, Wednesday, April 5, 2017 Did you not find the Transorbs added capacitance upset things? I found the drain waveform was considerably deteriorated when I experimented with Transorbs to limit spikes. > Hi all > The Decca PA seems to be scattered with spike limiting diode from > memory Transils / Transorb TVS diodes. (don't know the values) I > usually put one in the drain set above the peak drain wave voltage > seen on the scope and below the peak operating value of the FET  So far so good in single ended amps. > Jim M0MBU did a short treatise see > http://www.wireless.org.uk/guard.htm. > The Decca TX "guard circuit" by Jim Moritz, M0BMU. > 73 petefmt mailto:dead_fets@gmail.com