Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id wB5Kuwd6005661 for ; Wed, 5 Dec 2018 21:56:59 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gUeAb-0002pM-1h for rs_out_1@blacksheep.org; Wed, 05 Dec 2018 20:53:21 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gUeAa-0002pB-PQ for rsgb_lf_group@blacksheep.org; Wed, 05 Dec 2018 20:53:20 +0000 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1gUeAZ-00018y-5h for rsgb_lf_group@blacksheep.org; Wed, 05 Dec 2018 20:53:19 +0000 Received: from submission (posteo.de [89.146.220.130]) by mout01.posteo.de (Postfix) with ESMTPS id 9A9781600C2 for ; Wed, 5 Dec 2018 21:53:01 +0100 (CET) X-DKIM-Result: Domain=posteo.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1544043182; bh=dwlnsDo0LAFS0bGr1BJDE3+trUI2fN2aSBrIyREOlMs=; h=Date:From:To:Subject:From; b=BOeNtSEb4cN39R1SzrTk2KP1AyGtwZL5v41xLf8iux96EaNo81QmM71kuWVWoO78q /Ph71erp0J9/LHeO9q24mwcVvij4W50r+NmJLAAqqdhOAZSAJiiHvePurQrFxFI+fE NNJzHe3IAfO5ORS/rsYGXX3wrEu0Exa6griP8Q+Z2+9JscndI/wxbfuNZiuHVwFh3B aw+wlFehyMHqm8Ng+CHI852/ojHZkRG3zqD1h//41j8+Ac6IIA+kIdw6gMtw5q8i/F cDWEZcZWQoAheBQG3XsFbb8sCDcbkenPal/B3VF2iuK5yh0tGDpZSmLP+ZetR4ZgBq m4H8osL3XGJVg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4399sW0NqPz6tsW for ; Wed, 5 Dec 2018 21:52:30 +0100 (CET) Message-ID: <5C083A8E.6040708@posteo.de> Date: Wed, 05 Dec 2018 21:52:30 +0100 From: DK7FC 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: <484123806.20181205171236@gmail.com> <5C082969.9080400@posteo.de> <653985812.20181205202332@gmail.com> In-Reply-To: <653985812.20181205202332@gmail.com> X-Spam-Score: -2.3 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Am 05.12.2018 21:23, schrieb Chris Wilson: > I have got the photos of the bridge amp, very useful, will collect > bits! Could the choke wound on the iron core of a transformer be wound > on a scrap ma [...] Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [185.67.36.65 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 1f795a2ee1ecd56682b47ad11969b3d3 Subject: Re: LF: JT9-1 questions Content-Type: text/plain; charset=ISO-8859-1; 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 Am 05.12.2018 21:23, schrieb Chris Wilson: > I have got the photos of the bridge amp, very useful, will collect > bits! Could the choke wound on the iron core of a transformer be wound > on a scrap mains transformer toroid instead Stefan? Hi Chris, Yes of course. I took a 50 VA transformer core. Of course it can be a bigger core. The idea is to reduce the mains current spike when charging the caps. Depending on your mains impedance that peak current can be very high, a factor 10 above the rms value maybe. WIth the series L you can reduce that a bit. A more professional way would be to build a PFC supply, as used in most modern high power SMPS. But this is a project on its own. I didn't start it yet because it was not necessary. OK, i'll take the photos from the server again. 73, Stefan