DOCSLIB.ORG

PEARL Archive of Vacuum Tube Technology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
PEARL Archive of Vacuum Tube Technology Web: http://www.pearl-hifi.com 86008, 2106 33 Ave. SW, Calgary, AB; CAN T2T 1Z6 E-mail: [email protected] Ph: +.1.403.244.4434 Fx: +.1.403.245.4456 Inc. Perkins Electro-Acoustic Research Lab, Inc. ❦ Engineering and Intuition Serving the Soul of Music Please note that the links in the PEARL logotype above are “live” and can be used to direct your web browser to our site or to open an e-mail message window addressed to ourselves. To view our item listings on eBay, click here. To see the feedback we have left for our customers, click here. This document has been prepared as a public service . Any and all trademarks and logotypes used herein are the property of their owners. It is our intent to provide this document in accordance with the stipulations with respect to “fair use” as delineated in Copyrights - Chapter 1: Subject Matter and Scope of Copyright; Sec. 107. Limitations on exclusive rights: Fair Use. Public access to copy of this document is provided on the website of Cornell Law School at http://www4.law.cornell.edu/uscode/17/107.html and is here reproduced below: Sec. 107. - Limitations on exclusive rights: Fair Use Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, includ- ing such use by reproduction in copies or phono records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for class- room use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include: 1 - the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; 2 - the nature of the copyrighted work; 3 - the amount and substantiality of the portion used in relation to the copy- righted work as a whole; and 4 - the effect of the use upon the potential market for or value of the copy- righted work. The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors ♦ PDF Cover Page ♦ ♦ Verso Filler Page ♦ Triode Operation of KT88s ROBERT M. VOSS AND ROBERT ELLIS';' In response to many requests, and after a great depl of effort, the authors present a higher-powered version of their ten-whtt all-triode amplifier. HE BRITISH KT88 power pentotle. hig brother of the much respected KT6t3, Tquickly became popular after its ill­ troduetion ill this country not too long ago. Audiofaus no longer had to couple four tubes in push-pull parallel in order to get enough powel' to t:lrin' a low effi­ ciency spl'ake�·. In addition to its tapped-screen IIdapt­ ability, the KT88 11<lS previously ullex­ plored possihilities in lower power alll­ plifiers when nsed as it triode. A card to British ludustries Corp. brought bllck complete dllta on the tube, including the followillg inforllllltiou 011 tr'iod(' opel'll­ tion: Eb 485 v 10 170 ma I"wz Big 180 11111 560 oh illS (pel' tube) Ein (g_g) 70 v R,(A-A.) 4000 ohm POlit 27 '" D 1-3% First to clttch our eye were the zero lind maximum sigll:!1 currents; the total • 697 West End Au., New YorK 25, N.Y, Fi9. 2. B::ttom view of the amplifier. Note 'twisted filament leads and ground buss. \'arilltion is less than 6 pel' cent, mean­ illg that Olll' power supply requirements w('I'e grelltly simplified. So fal' so good. The load impedance of 4000 ohms is, howeyer, a problem. \Ve know of 110 pre­ viously dcsigned tubes mellnt to work into sHch a load except in ultralincar operlltion, and transforlllers with screen taps lire expensi\'e. vVe settled for a Triad S-42A which is wound for 4500 Oh:IIS, :Iud, by jnggling the operating pal'llilleters a bit, ,vere still able to ob­ Fig. 1. Top view of tllin 25 watts.1 The S-42A is rated lit 50 completed ampli­ \\'atts, which mellns that power at fre­ fier. quency extrcmes will not drop off be­ cause of poor output transformer powel' hllndling capability. The amplifier deli\'­ ers the full 25 watts lit 18 cps, (the lower limit of our generator) and only slightly less at 20,000 cps. The Power Supply As we mentioned beforc, the low cur­ rent fluctuation of the output stage sinl- 1 Au ud"autage of triodes is that using too high a load impedance will not increase distortion although it will decrease power. 30 AUDIO • MARCH, 1961 plifies the power supply. A single GZ34 l'ectifier feeds what is essentially a ca­ 0.1 pacito r input filter. A fter an LC net­ ��"��"--����++�----������P-"�� +-��4---� work to the output stage supply, B+ goes I '.0 - through resistance-capacitance filters to - r ----1--+-l-+-H-+-H----+-++-++ -++t+--'·08••�a="·.J'>I- ''.>� ""�I'J',�t+f.++- ---4 the earlier stages. The preamp power 110.. ,-H4--�i ' take-ofI sockt't will supply sufficient ����I��--+--+-+-r�+++---r-r-r;��Hr-���- - -- -H--ilft+rr---I-++H-tt+t--+--'V-:>- · f--- J' power to most un powered control units. ! I. The 10-ohm resistor is a device recom­ GAIN, .8 f INPUT FOR 25 WATTS OUTPUT . -HUM & NQISE,(BELOW 25 WATTS OUTPUT)I--+-f-H+tt-ft---t mended hy t.he Dyna Co. to avoid _r- II INPUT OPEN-73 db ground loops. If you 're 110t powering a I-+++f-t-T-H--...L.-t-l-+-+m INPUT SHORTED-90 db preamp, make up a shorting plug with t--f- ju mpers fl'om pins 6 to / (to turn 011 the amplifier), and pins 4 to 8 (to place bias on the heaters). -'- I-+-+-+-ht-t++ The Audio Circuit '0 100 I • � 1000 I. "0000 IfXJOO!> To drive the output stage, we used the FREQUENCY IN CYCLES PER SECOND cathode-coupled phase splitter, with Fig. 4. '!Frequency response. which we and other d('sig lers have had l value capacitors, using them to e�tend men(ls s('pn rate cathode resistors for the excellent results. Driving the inverter, the low-frequency response below' that output tuhes, we used Il com1110n res is­ and determining its operating point, is of the output transformer. We cho e the tor, mainly hecause we are using a n conventional voltage amplifier. The J second alternative, because the firs� pre- matched pllir of tubes. TI�e control grid phase splitter, which is capable of de­ � arc th sents p ase-shift problems which nke nn<l screen dllmplllg resistors e livering almost o ts of audio, has h 200 v l recommended hy Gl'n('lex. it somewhat unpredictable you Iwllnt vnlues a balance con trol in its plate circuit, . If to reduce bass response, perhaps pro- ahout which \I'e shall speak later. t1 Construction tect a delicate spea er ut a ca o There nre two methods of achieving k , p P it r Use a very large chassis for the am­ low freque ncy stability within a feed­ before the input grid resistor. B no plifier; the coupling capacitors and elec­ fl back loop. One is to use small coupling means tamper with the values insidJ the trolytics take up a great delll of room cnpaeitors and hope for a sharp cutoff feedback loop, or the amplifier mElY go under the chllssis, and Genelex recoru­ without a siguificant hump at the knee. wild in the subsonic region. I mends a mini1l1um of four inches between The other \I'ay involves the use of high- Although Genelex quite clearly recoJU- the KTS8's. Standard construction practice (iso­ lated ground, twisted filament leads, (300v) etc.) will help in nchieving the potentinl of the circuit. There are however, [I cou­ ple of things worth remelllbel'ing. First, a word of caution in n,fel'ence to the filament win<lings. When we first turned on the aJllplit1er, it illlmediately blew the fuse. After a bit of head scratching, we tried reversing the leads of one of the windings. This clll'ed the trouble; they had been bucking. Color coding won't help you here; trial and errol' is the only way to insure COl'l'ect phasing. Secondly, several electrolytics are tu hnlnrs instead of the common chassis'lllounted cans. Therefore, if you're unfamili[ll' with this type of work, it pays to take a little extra time looking for hidden shorts under the chassis. Finally, before C011- necting the feedback loop permanently, check hy soldering only one side a 11(1, with a signal going through the ampli­ fier, touch the other side quickly. If the sound goes down in volume, well and good; if it makes a loud buzzing sound, reverse the lends from the output trans­ former to the KT88s. Then attach n load to the amplifier and use a signal gen­ erat.or to feed into the amplifier a 1000 cps signal which is loud enough to be heard. Then adjust the balllnce control for equal sigllllls at the plates of the KT88's.2 \Yith this taken care of, solder 2 Better yet; if you have the equipment, connect the feedback loop and adjust the balance control for lowest Dr at about 2 Fig. 3. Schematic diagram of 25-watt amplifier. watts. 32 AUDIO • MARCH, 1961 thc ft'edlJal'k l'('sistor and capacitor in position, shake the hits of wire and sol­ der out of thc chassis and you're through.
Load more

Recommended publications
  • 6C33C-B OTL Amplifier - Background and OTL Circuits
    6C33C-B OTL Amplifier - Background and OTL Circuits http://www.audiodesignguide.com/otl/aria.html Tube Lovers Anonymous 6C33C-B OTL Amplifier - Background and OTL Circuits INTRODUCTION The purpose of this paper is to explain the selection process and trade-offs involved in choosing the circlotron as the optimal topology for a high-power OTL amplifier. The issues involved in making this selection include circuit simplicity, balanced performance under small- and large-signal operation, and achieving low output impedance (and hence a high damping factor) without the excessive use of feedback. BACKGROUND For many of us, the vacuum tube remains the only acceptable electronic component for amplifying music. Endless debates and discussions on the merits of solid state versus tubes rage on, but we find that the transparency and realism offered by a device consisting of metal and vacuum just cannot be matched by silicon for sheer musical enjoyment and getting as close as possible to the original sound. Prove what you like, tell us we're imagining things, but we know it just sounds better. However, by insisting on all-tube amplification, there is classically a major penalty to be paid in the power amplifier. Tubes are simply not designed to couple directly to today's modern low impedance speakers, and a transformer must be used to match the power output to the load. Even with finest modern materials, the output transformer remains the weakest link. At low frequencies its finite inductance steals current away from the load, and at high frequencies its stray capacitance, leakage inductance, and high-frequency copper losses combine to attenuate amplitude and introduce severe phase shifts.
    [Show full text]
  • A 25W OTL Tube Amplifier Presenting a New Output-Transformerless Circuit with Direct Coupling to the Loudspeaker
    Copyright Segment LLC. This article cannot be reprinted without permission: [email protected]. To subscribe: www.circuitcellar.com/subscription/ t u b e s By Tim Mellow A 25W OTL Tube Amplifier Presenting a new output-transformerless circuit with direct coupling to the loudspeaker. f you have spent $500 or more more in common with the Futterman ample loop DC feedback, which—after on 5m or so of exotic loudspeak- circuit2, except that a long-tailed pair initial adjustment—keeps the offset er cable, have you ever wondered of pentodes is used for the driver stage voltage within 20mV between tube re- I about the 500m of standard copper instead of the concertina phase splitter. placements. Similarly, the DC bias needs wire in the output transformers of your The pentodes provide the current drive hardly any adjustment over time. tube amplifier? Audio output trans- as well as greater voltage swing than I know that signal feedback is a con- formers are large, expensive compo- triodes. troversial issue and there are those who nents that require complicated winding A general aim of the design was to maintain that the ultimate goal should arrangements in order to work properly have as simple a circuit as possible with be 0dB. However, zero feedback in this at high frequencies. They are the prime a minimal number of components in design would result in audible noise culprits for the soft bass sound associ- the signal path as well as push-pull op- and an output impedance of 8Ω, which ated with tube amplifiers. eration throughout (Fig.
    [Show full text]
  • Controlled Audio Valve Amplifier
    Associac¸ao˜ Portuguesa de Engenharia de Audio´ Secc¸ao˜ Portuguesa da Audio Engineering Society Artigo Apresentado no 13◦ Encontro da APEA 7 e 8 de Outubro de 2011 ESMAE O artigo apresentado nesta Conferenciaˆ foi seleccionado com base num resumo estendido revisto por pelo menos dois revisores anonimos´ qualificados. Este artigo foi reproduzido pelo manuscrito previamente fornecido pelo autor, sem qualquer edic¸ao,˜ correcc¸ao˜ ou considerac¸oes˜ do quadro de revisores. A APEA nao˜ se responsabiliza pelo conteudo´ apresentado no artigo. Todos os direitos reservados. E´ proibida a reproduc¸ao˜ total ou parcial do conteudo´ deste artigo sem permissao˜ directa da Associac¸ao˜ Portuguesa de Engenharia de Audio´ . Controlled Audio Valve Amplifier Tiago Campos1,V´ıtor Tavares1, Ricardo Carvalho1 1DEEC - Faculdade de Engenharia da Universidade do Porto, 4200-465 Porto, Portugal A correspondenciaˆ devera´ ser enderec¸ada para: Tiago Jose´ da Silva Campos ([email protected]) ABSTRACT Valve amplifiers are well known for their typical problems. Valves tend to age and deteriorate much faster than solid-state devices, making their characteristics to drift quicker with time of use. Consequently, these amplifiers need particular care on this issue, being necessary a regular calibration of bias currents at the output stage, usually adjusted by the user or technicians. It should be also noted that these circuits are known for having typically higher levels of distortion when compared to transistorized amplifiers. Because valves have relatively low amplification factor and also because of large phase shifts, mainly caused by the output transformers, high amounts of (global) negative feedback are not admissible. In opposition, with solid-state amplifiers huge amounts of feedback are generally employed, making transistor amplifiers to present superior linear characteristics.
    [Show full text]
  • The PEARL Archive of Vacuum Tube, Loudspeaker & Solid State
    Web: http://www.pearl-hifi.com 86008, 2106 33 Ave. SW, Calgary, AB; CAN T2T 1Z6 E-mail: [email protected] Ph: +.1.403.244.4434 Fx: +.1.403.245.4456 Inc. Perkins Electro-Acoustic Research Lab, Inc. ❦ Engineering and Intuition Serving the Soul of Music The PEARL Archive of Vacuum Tube, Loudspeaker & Solid State Audio Technology Updated approximately monthly; this is Ver. 1.10, May 1, 2014. To obtain the most recent version of this document click here Click on blue text in the Volume/Section listings to be taken directly to the web page where the articles can be downloaded. HE FOLLOWING IS A COMPLETE INDEX of the arti- Titles of presently downloadable articles are Tcles contained in the P EARL Archive of Vacuum shown in blue text, clicking on which will take you to Tube, Loudspeaker and Solid State Audio Technology. the relevant page on our site. Presentl spanning 16 volumes that cover a wide range of topics, the ‘Archive is a collection of approxi- This latest release is expanded from the original mately 1,200 articles that chronicle the implementation intent back in the late 1980s to provide an extensive of vacuum tubes in the audio-reproduction chain from archive of only vacuum tube technology as imple- the late 1920s through to the present day. mented in audio to include the very large amount of While we might at some point make the entire col- information amassed up the present; early 2014. lection available on DVD, the scanning, page-by-page reconstruction and conversion to OCR-d PDF of at least 5,000 pages is a very time consuming project that will not be completed for some time.
    [Show full text]
  • HI-FI+ GUIDE to PERSONAL AUDIO Sponsored by Hifiman and Echobox Audio
    HI-FI+ GUIDE TO PERSONAL AUDIO Sponsored by HiFiMAN and Echobox Audio HI-FI+ GUIDE TO PERSONAL AUDIO GUIDE TO PERSONAL AUDIO HI-FI+ The Explorer The Explorer represents the evolution of portable audio, and our refusal to accept the limitations of digital audio. Smartphones, with their mediocre DACs, integrated, noise-prone circuitry and lossy files, just don’t do justice to the emotion behind our favorite music — that's why we've carefully crafted the Explorer using nothing but the the highest quality components to recreate a portable listening experience that's as close to real vinyl as it gets on-the-go. #AUDIOEVOLUTION Echobox is a company founded and run by music-lovers and audio geeks. We’ve been watching the personal audio industry for years, researching and analyzing everything from the types of music people listen to, how and where we listen, and, most importantly, the quality of audio. The truth is, there are a lot of fashion oriented headphones and earphones in the market today. Most sound mediocre, are built like dollar store toys, or are The Finder X1 just way too expensive for the quality they provide. We’ve founded Echobox to help The Finder X1 is a revolutionary new HiFi personal audio evolve in a way that does justice to good music. Our goal is simple: make earphone that, in many ways, is the first of its great sounding audio products that are well built and affordable. kind. Combining innovative structural engineering and the highest quality materials, we have created an earphone that sounds powerful, lively and transparent, while setting a new industry standard for durability.
    [Show full text]
  • Cars, Planes, and Circlotrons John’S Response
    2003 John Broskie's<< Guide TUBE to CAD Tube JOURNAL Circuit Analysis >> & Design Page October www.tubecad.com 2003 An Experiment Many of you miss the old Tube CAD Journal, the one that was once published along a fairly regular schedule, the one that held several articles per issue and a Article readers’ letters section. What happened to the old Tube CAD Journal? Cars, Planes, In spite of over 50 articles, hundreds of schematics and well over a and Circlotrons thousand emails, I believe the TCJ was never given a real chance to prove itself. It was the Cinderella that only received scraps of time and effort. Since it drained both money and time -- lots of time -- it was resented by family and friends. The Tube CAD Journal companion programs did not solve the dilemma. Thus I have devised an experiment to see if the Tube CAD Journal can support itself, allowing me to devote the many hours it would take to publish once again a full journal each and every month; in fact, my goal would be to produce a better journal than the old one. My vision for this reborn TCJ includes a strict publishing schedule, optimized PDF format, tube-based audio projects, and the return of reader mail. Because of the way the Yahoo! Store works, I will have to make this experiment a “limited time offer.” So in order to make it something you can buy for yourself and all your tubehead friends for Christmas, Hanukkah, Kwanzaa, Winter Solstice, New Year’s, Festivus or any other winter celebration you desire, I will be announcing the experiment the week of the American Thanksgiving holiday (that’s the week of November How to contact the 24th, for those of you outside the U.S.).
    [Show full text]
  • Mode of Operation of the Pentode Or Tetrode Tube in the Output Stage Of
    Web: http://www.pearl-hifi.com 86008, 2106 33 Ave. SW, Calgary, AB; CAN T2T 1Z6 E-mail: [email protected] Ph: +.1.403.244.4434 Fx: +.1.403.245.4456 Inc. Perkins Electro-Acoustic Research Lab, Inc. ❦ Engineering and Intuition Serving the Soul of Music Please note that the links in the PEARL logotype above are “live” and can be used to direct your web browser to our site or to open an e-mail message window addressed to ourselves. To view our item listings on eBay, click here. To see the feedback we have left for our customers, click here. This document has been prepared as a public service . Any and all trademarks and logotypes used herein are the property of their owners. It is our intent to provide this document in accordance with the stipulations with respect to “fair use” as delineated in Copyrights - Chapter 1: Subject Matter and Scope of Copyright; Sec. 107. Limitations on exclusive rights: Fair Use. Public access to copy of this document is provided on the website of Cornell Law School at http://www4.law.cornell.edu/uscode/17/107.html and is here reproduced below: Sec. 107. - Limitations on exclusive rights: Fair Use Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, includ- ing such use by reproduction in copies or phono records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for class- room use), scholarship, or research, is not an infringement of copyright.
    [Show full text]
  • Glossary Posted by Akhilesh on Thu, 16
    Subject: Glossary Posted by Groove Tube on Wed, 15 Sep 2004 18:37:09 GMT View Forum Message <> Reply to Message What we really need is a good detailed technical glossary. Maybe if everyone will help to fill in the blanks so to speak, we can build a good FAQ here. It's hard to sort out all the details both technical and subjective. It would be great to have a lits of all the popular terms and topics, along with a technical description, strengths/weaknesses and most importantly a subjective description on what it sounds like, what it offers in terms of musicality.Here is a small list, and there are probably others. Please jump in an fill in the blanks because I think this could be a very useful list.SET - Single Ended Triode or Single Ended TubePP - Push PullNFB - No feedbackUL - Ultra LinearOTL - Output Transformer-LessDC - Direct CoupledTC - Transformer coupledParafeed - Parallel transformer coupledWhat does it all mean? What is the difference between pentodes and triodes in terms of sound? Aren't there other amplifier tube types too? Subject: Re: Glossary Posted by akhilesh on Thu, 16 Sep 2004 13:06:03 GMT View Forum Message <> Reply to Message HI,NFB = Negative feedbackIMHO, it would be simplsitic to make a sweeping statement that one sounds better than the other. A SET can sound better or wrose than a PP, and so on. It really depends on the individual design and execution of the circuit. Synergy woth other components, esp. speakers is also a huge factor.-akhilesh Subject: Re: Glossary Posted by Groove Tube on Thu, 16 Sep 2004 16:51:27 GMT View Forum Message <> Reply to Message Thanks for the correction.
    [Show full text]
  • In This Issue This Issue Hybrid Amplifiers
    April-May << April-May 2001 2001 The Journal of ^^ Tube TUBE Audio CAD Circuit JOURNAL Design ^^ Volume 3 Number 3 >> This Issue Hybrid Amplifiers Another issue, and a fat one at that. Amazing. The promise made is that the palpability and This journal’s future may be uncertain, but this issue sweetness of tubes can be added to the power and moves forward. Have you ever noticed how difficult slam of solid-state. Or at least that is what the it is to read a schematic with a white background, advertising copy claims. (Ever notice how often a particularly on a computer screen? The contrast is solid-state amplifier is proudly described as sounding too great. Hence the gray backgrounds for this tube-like? Yet have you ever read of a tube amplifier issue’s schematics. Feedback is encouraged. Is it being proudly described as sounding solid-state- more readable? Do you like it? Does it print as well? like?) While some good hybrid amplifiers exist, too Hybrid amplifiers, comprising vacuum tube and many sound like bad compromises, often laden with solid-state, are covered in this issue. (Even those noise, dark tonalities, and poor bass definition, and readers who will not touch a solid-state diode should even sometimes stricken with gritty highs. What read this article, as the topologies are often directly went wrong? How was it possible to lose the transferable to pure tube OTL amplifiers.) We look attributes and retain the faults of both technologies? at several topologies and try to weigh the advantages Sometimes the blame rests with the designer who and liabilities of each.
    [Show full text]
  • High Performance Audio Power Amplifiers
    High Performance Audio Power Amplifiers for music performance and reproduction Newnes An imprint of Butterworth-Heinemann Ltd Linacre House, Jordan Hill, Oxford OX2 8DP A division of Reed Educational and Professional Publishing Ltd OXFORD BOSTON JOHANNESBURG MELBOURNE NEW DELHI SINGAPORE First published 1996 Reprinted with revisions 1997 © Ben Duncan 1996 © B. D. 1997 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P 9HE. Applications for the copyright holder's written permission to reproduce any part of this publication should be addressed to the publishers TRADEMARKS/REGISTERED TRADEMARKS Computer hardware and software brand names mentioned in this book are protected by their respective trademarks and are acknowledged. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 0 7506 2629 1 Typeset by P.K.McBride, Southampton Printed and bound in Great Britain High Performance Audio Power Amplifiers for music performance and reproduction Ben Duncan, A.M.I.O.A., A.M.A.E.S., M.C.C.S international consultant in live show, recording & domestic audio electronics and electro-acoustics. Foreword Ben Duncan is one of those rare individuals whose love and enthusiasm for a subject transcends all the usual limits on perception and progress.
    [Show full text]
  • Vacuum-Tube-Valley-I
    EL84 - The Baby ·With Bite ~ -3008 lval•atlon \\ \ A Music Lover's Triode \ ) I / / ' \, i l Sweep Tuite OTL Prolect 200 Watt EL509 Amp i I ' t RCA Tulle Manufactur n 1 CUI i§·i il·J• i ,i it-Sil it·) ii ~feu h ninql,,am RArno ~ R d d i d t r o n TIJ!!s Illustration by Ken t Leech EDITOR'S P A G E A ND INDUSTRY N E W S advice to unsuspecting beginners. We also has sets of replacement indicator would advise these "experts" to do some light jewels for $4.25/set of five . VTV Issue# a more research before spreading misin­ The Fisher Doctor Table of Contents: formation. 27 Daleham Street This si tuati on is even worse on Staten Island, NY 10308 rec.audio.tech, rec.audio.high-end (718) 948-7489 ,El84: The Baby with Bite ••••• 3 and alt.guitar.amps. And the World Wide Web with its seemingly millions Counterfeit NOS Tube Boxes Listening to the EL84 •••••••••••• 8 of commercial websites has become the Steve Martin of Antique Electronic -~weep Tube OTL Amp •••••••• 10 ultimate last resort for charlatans and Supply notified us of an individual in rip-off-artists. T here are no controls, Hong Kong who is producing fake :'R~A Tube Manufacturing•••• 15 regulations or second opinions. At least NOS-type tube boxes. The company in wi th newsgroups, anyone spouting crap question is producing boxes with: . Radiotron Handbook••••••••• 18 will be called on it by others. If you Amperex, RCA, Tung-Sol, Telefunken plan on buying anything off the web, be and Mullard brands.
    [Show full text]
  • Binder Style Circuits Ver.1.Pub
    1 Tube CAD Circuit Guide GlassWare AUDIO DESIGN SOFTWARE Version 1.1.2 Circuit Guide 2 Tube CAD Circuit Guide DISCLAIMER This program and User Guide are intended for amusement and instructional purposes—solely. We at GlassWare assume no responsibility for the use of any of the information provided. Much of what is detailed in the User Guide and program refers to potentially lethal voltages. Always let an electronically trained person review what you are planning on building and what you have built. Copyright© GlassWare 1997,1998, 2001 All rights reserved. No part of this publication may be reproduced, transmitted, stored in a retrieval system, or translated into any language by any means without the permission of GlassWare. Windows is a registered trademark of Microsoft. Other products mentioned are trademarks or registered trademarks of their respective companies. GlassWare™ www.glass-ware.com USA 3 Tube CAD Circuit Guide I NTRODUCTION C ASCODE AMPLIFIER Just how many fundamentally distinct, audio, single triode During the 1980’s, the Cascode used to be the circuit of circuits are possible? (A comparable question was posed in choice in high-end audio gear because of its potential for a chess book once and its answer was staggering: How high gain, low noise, wide bandwidth, and because it had many moves are theoretically possible in the first ten not been used much before, making it seem fresh and bold. moves of a game of chess? The answer: more than the Fashion occurs in electronics, as well. number of atoms in our solar system.) “CASCODE” is a contraction of “CASCaded triodes with A quick review of the possible configuration options yields: the gain of a pentode and the low noise of a triODE.” It is input at the grid or the plate or the cathode or any two ele- built up of one triode in current series with another triode.
    [Show full text]