Return-Path: Received: (qmail 90338 invoked from network); 29 Jun 2004 11:11:32 -0000 Received: from unknown (HELO ptb-mxscan02.plus.net) (212.159.14.236) by ptb-mailstore02.plus.net with SMTP; 29 Jun 2004 11:11:32 -0000 Received: (qmail 79660 invoked from network); 29 Jun 2004 11:11:30 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore02.plus.net (212.159.14.216) by ptb-mxscan02.plus.net with SMTP; 29 Jun 2004 11:11:15 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1BfGWB-000JOT-Bu for dave@picks.force9.co.uk; Tue, 29 Jun 2004 11:11:15 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1BfGVM-0002Xr-CA for rs_out_1@blacksheep.org; Tue, 29 Jun 2004 12:10:24 +0100 Received: from [213.232.95.59] (helo=relay.salmark.net) by post.thorcom.com with esmtp (Exim 4.14) id 1BfGVL-0002Xi-HN for rsgb_lf_group@blacksheep.org; Tue, 29 Jun 2004 12:10:23 +0100 Received: from mxsf03.cluster1.charter.net ([209.225.28.203]) by relay.salmark.net with esmtp (Exim 4.24) id 1BfN3k-0003h8-C6 for rsgb_lf_group@blacksheep.org; Tue, 29 Jun 2004 19:10:20 +0100 X-Fake-Domain: mxip05.cluster1.charter.net Received: from mxip05.cluster1.charter.net (mxip05a.cluster1.charter.net [209.225.28.135]) by mxsf03.cluster1.charter.net (8.12.11/8.12.11) with ESMTP id i5TBATof000996 for ; Tue, 29 Jun 2004 07:10:30 -0400 Received: from cpe-66-189-53-169.ma.charter.com (HELO johncellarnew) (66.189.53.169) by mxip05.cluster1.charter.net with SMTP; 29 Jun 2004 07:10:03 -0400 X-Ironport-AV: i="3.81R,138,1083556800"; d="scan'208"; a="70040240:sNHT12680144" Message-ID: <001a01c45dc1$509db2c0$0500a8c0@charter.net> From: "John Andrews" To: rsgb_lf_group@blacksheep.org References: <40E13F3D.1951.2BEAEC@localhost> Date: Tue, 29 Jun 2004 11:10:33 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=no,RCVD_IN_SORBS=0.1 Subject: LF: Re: Linear amp? Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com 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-PN-SPAMFiltered: yes X-Spam-Rating: 1 Mike, > Can anyone point me at a design for a linear amplifier > suitable for running data modes such as PSK08 or WOLF? Not many seem to be doing this any longer, but an audio power amplifier is a possibility. I'm using an unmodified Hafler P3000 amp at the 200 watt level. Picked it up from eBay at considerably less than the new price. I confess to not having made any linearity measurements, though, and it's possible that the thing is less than perfect. I haven't gone beyond 100 watts in the continuous key-down modes, partly out of respect for the present output transformer and low pass filter. All of the bits are here for heftier versions of both, and they should be ready for the next season. I do have two small fans blowing air through the amp's heat sinks, and that makes a big difference. John Andrews, W1TAG/WD2XES