Return-Path: X-Spam-DCC: paranoid 1169; 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=-2.5 required=5.0 tests=BAYES_00,FORGED_RCVD_HELO autolearn=unavailable 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 s68CsUvM006587 for ; Tue, 8 Jul 2014 14:54:30 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1X4Uqg-0007Sb-GE for rs_out_1@blacksheep.org; Tue, 08 Jul 2014 13:50:18 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1X4Uqg-0007SS-8V for rsgb_lf_group@blacksheep.org; Tue, 08 Jul 2014 13:50:18 +0100 Received: from mail.foreach.it ([195.88.7.228] helo=for04.foreach.it) by relay1.thorcom.net with esmtp (Exim 4.82) (envelope-from ) id 1X4Uqe-0004Gx-HQ for rsgb_lf_group@blacksheep.org; Tue, 08 Jul 2014 13:50:17 +0100 Received: from localhost (localhost [127.0.0.1]) by for04.foreach.it (Postfix) with ESMTP id 7EB66444 for ; Tue, 8 Jul 2014 14:50:15 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at for04.foreach.it Received: from for04.foreach.it ([127.0.0.1]) by localhost (for04.foreach.it [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QJTjxvfkgMkR for ; Tue, 8 Jul 2014 14:50:11 +0200 (CEST) Received: from imac2 (host185-41-static.24-87-b.business.telecomitalia.it [87.24.41.185]) by for04.foreach.it (Postfix) with ESMTP id CD10843D for ; Tue, 8 Jul 2014 14:50:10 +0200 (CEST) X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Tue, 08 Jul 2014 14:50:09 +0200 To: rsgb_lf_group@blacksheep.org From: Marco IK1ODO -2 In-Reply-To: <1404815801.86408.YahooMailNeo@web173004.mail.ir2.yahoo.com > References: <9FE61D98573D45E08A39735EF283914F@gmc.net> <53BAE6E9.3050206@tele2.se> <1404795548.36812.YahooMailNeo@web173001.mail.ir2.yahoo.com> <1404815337.38505.YahooMailNeo@web173004.mail.ir2.yahoo.com> <1404815801.86408.YahooMailNeo@web173004.mail.ir2.yahoo.com> Mime-Version: 1.0 Message-Id: <20140708125015.7EB66444@for04.foreach.it> X-HELO-Warning: Remote host 195.88.7.228 (mail.foreach.it) used invalid HELO/EHLO for04.foreach.it - verification failed X-Scan-Signature: 4d4a9e8f68fb15c54898568240f542c5 Subject: Re: Fw: LF: Pure off-topic: old tubes Content-Type: text/plain; charset="us-ascii"; format=flowed 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 30 15 years ago I was used to buy truckloads of test and communication equipment from Johns Radio in Bradford (now he is in Batley). He had a lot of equipment from the closure of STC R&D labs. I acquired many valve handbooks: AEI, GEC, STC, RCA, about 20 books. I dug and found some data on a similar tetrode, possibly a newer version of 4B/55. I have 4B/550E, 4B/551B, 4B/551BD. It is in Volume 2B, Components, of S.T.C. Please find the scan in www.spinelectronics.eu/ftp/STC_tetrodes.pdf Petr, do they look similar? 73 - Marco IK1ODO