Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbosgd!cwruecmp!nitrex!rbl From: rbl@nitrex.UUCP Newsgroups: sci.electronics Subject: Re: Power Supplies for Tube Circuits. Message-ID: <487@nitrex.UUCP> Date: Mon, 13-Jul-87 09:42:09 EDT Article-I.D.: nitrex.487 Posted: Mon Jul 13 09:42:09 1987 Date-Received: Thu, 16-Jul-87 01:06:15 EDT References: <12887@rose.UUCP> <8240@utzoo.UUCP> <485@jetsun.weitek.UUCP> <622@neoucom.UUCP> Reply-To: rbl@nitrex.UUCP ( Dr. Robin Lake ) Organization: The Standard Oil Co., Cleveland Lines: 41 In article <622@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: > > ..... > > >The high gain preamps were also usually isolated from the chassis >by rubber or springy metal strips. The idea was probably to combat >microphonics from picking up vibrations of the fan. (Quite a big >fan was necessary to cool down a 551 with its complement of 111 >tubes! -- and it had a separate power supply with about a dozen >more tubes for regulating all voltages). Shock mounting the amp >would probably be useful in combating feedback from the speakers. > I've been told that the policy at Tektronix was that a 'scope should survive a fall from a 3 foot high table onto a concrete floor! The springies etc. helped the equipment fulfill this goal. >One thing that has puzzled me is that some Tektronix plug-ins have >flat rubber coated resistors. I've wondered what the purpose of >doing so was. I've never seen any references as to why. > From the fuzzy dark reaches of my mind, I recall this resistor configuration had something to do with reducing the inductance of the resistor. Thick-film technology, as I recall. > > >Hope this was of some use. >Bill >(wtm@neoucom.UUCP) There is an ART and there is a SCIENCE. VERY occasionally, a for-profit organization can afford to bring the state-of-the-art along with an excellent appreciation of the science and actually produce a OPRODUCT with the best of both! Rob Lake (rbl@nitrex.UUCP) Disclaimer: This in no way reflects any opinion of my employer nor any knowledge gained while in my current employment.