Return-Path: Received: (qmail 12303 invoked from network); 5 Dec 2000 13:05:13 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 5 Dec 2000 13:05:13 -0000 Received: (qmail 9919 invoked from network); 5 Dec 2000 13:00:17 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 5 Dec 2000 13:00:17 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 143HYT-00076c-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 05 Dec 2000 12:50:45 +0000 Received: from orodruin.esoterica.pt ([195.22.0.166]) by post.thorcom.com with esmtp (Exim 3.16 #1) id 143HYP-00076V-00 for rsgb_lf_group@blacksheep.org; Tue, 05 Dec 2000 12:50:42 +0000 Received: from ea.esoterica.pt (ea.esoterica.pt [195.22.0.204]) by orodruin.esoterica.pt (8.11.0/8.11.0) with ESMTP id eB5CoYe14415 for ; Tue, 5 Dec 2000 12:50:34 GMT X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from slave-6 (por097.esoterica.pt [195.22.5.97]) by ea.esoterica.pt (8.9.3/8.9.3) with SMTP id MAA07735 for ; Tue, 5 Dec 2000 12:50:32 GMT Message-ID: <3.0.5.32.20001205125228.00796b20@pop3.esoterica.pt> X-Sender: brian@pop3.esoterica.pt (Unverified) X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.5 (32) Date: Tue, 05 Dec 2000 12:52:28 +0000 To: rsgb_lf_group@blacksheep.org From: "Brian Rogerson" Subject: Re: LF: Looking for 2-3 Watt Linear PA for LF In-reply-to: <200012050541_MC2-BD39-AEBD@compuserve.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Geri, >Does anyone of you have a proven scheme of a small linear PA available, >that delivers about 2 or 3 Watts from 10 mW, preferably from 18 Volts >(which is the voltage used by the exciter)? I am sure a small audio >amplifier would do ... I have spent months fighting the TDA2030 which is only marginally stable. About three weeks ago I tried a LM1875, which has better bandwidth and can be used down to a closed loop gain of 10dB. I am now using three (one preamp and two in a bridge circuit) to drive two of David MRF amplifiers in parallel. This IC is specified for +/- 24v but seems to work quite happily on +/- 12v. 73, Brian 73 Brian CT1DRP IN51QD 41 09 58N 08 39 11W http://homepage.esoterica.pt/~brian