6L6 Shootout: 20 Types Tested /' ft. Story of Kllpacho... Out of the Corner & Into the Limelight le... 222 ... d LK·48 Sweet Sound for a Song 6528 MM1.'o.low... Single-Ended Amplifier Project Visit us on the web www.vacuumtube.com NEW SENSOR CORPORATION 20 COOPER SQUARE NEW YORK CtTY. NY 10003 FAX (212)529-0486 [email protected] WWW.SOVTEK.COM I D r 0 • 5 P A G • AN D NDU STRY Eric Barbour Wins Tyne Award Electro-Harmonix Launches New VTV Issue # 1 3 At the 38th Annual Conference of the EL34 Antique Wireless Association (AWA) on Table of Contents: Elecuo-Harmonix has announced its September 3,1999, vrvSenior Ediror new EL34EH fi rs in a Eric Barbour was awarded the Tyne which is the t line: of imp roved qual iry tubes for the year Interview with Paul Klipsch 4 Award. This award is given yea rly to an T h e EL34EH has gold-plated AWA member for recognit ion of work in 2000. screen grids, 11 [Unl':dbi-polar cathode Klipschom: Lore and Mods .. 6 documenting the hisrory of vacuum tube cover that optimilCS electron focusto the electronics. platC', p rec ision al ignmem and a propri­ Classic 2A3 Amplifier .....•.. l0 Mr. Barbour has wrinen sevenl art icl es erary {ri-alloy plate material the reduces Problems with Electronics .. 13 d ealing with th e h isto ry of audio and distorcion and odd-order harmonic;:s. other types of tubes for Vacuum Tube For more information, contact Electra­ .....•..•• Valley and Glass Audio magazines. He is Scott 222 ond LK48 15 Harmonix at: (212) 529-0466, (212) also a volunt�r for the Computer 529-0486 FAX or www.ehx.com Computing with Tubes .•...• 20 Musuem History Cente! in Mountain View, CA. He has help ed them docu­ Tube Collectors' A5Sociation Formed ASUSA K2003 Review.•..•.. 21 ment and reStore some of the Museum's A new Tube Collectors' Association i s historical vacuum tube COlllpmer now in operation. This is an organiza­ 6L6 Shootout ........•.•••••..... 22 exhibits. Eric manages the Vacuum Tube tion of collectors focusing on all phases, Applications Laboratory and p rovi d es [}'pe5 and vintages of tube technology. 6528 SE ArnpProject......... 26 cuStomer tcchincal support for Svetlana The association publishes a club bulletin Elcctronic Devices in Portola Valley, CA. and is plan ning tube collector events, Subminiature Tubes ...•..•....28 etc. For more info, contact Al Jon es at New Contributing Editors at VIV (707) 464-6470 or Ludwell Siblc:y at We an: pleased to announce two new (541) 855-5207 or send your mail Coming In the Next contributors to Vacuum Tube Vall ey: r(!(juest to: TCA, ro. Box J J 81, Medford, OR 97525 "sue of VTV: David Bardes is a loudsp�er enthusi­ aSt and a DIY. Dave will be rC!learching 12AX7 Shootout Vacuum Tube Valley Moves loudspeaker history and conducting inter­ - Exclusive Interview with views with famous loudspeaker designers. \Ve are moving! After doing business David Hafler of Dynaco In addition, he will be th e VTV Official in Sil icon Vall ey for five rears, wc are Product Re\' iewer. In the future, we will moving the VTV office and shop to - naco Tube Products n � be conducting re\· iews of reasonably­ no h of Napa Valley! The air is fresher, Historical Review priced loudsp eak ers, tube: CD players and the scenery is beautiful and there is a lot - Gillum G-3 Speaker Review tube amps and preamps. Dave's back­ less traffic. Business will be as usual g round is in professional photography (once we get t'V erything moved) and we - Direct Reactance Drive SE and video production. He is employed as will contin ue to operate the magazine Amplifier Project a product teSter for a well-known el ec­ and the audio tube and parts business. u m Please nOte the follow ing address - pp SV 83 Amplifer Project on idco puter products test lab. [email protected] changes: Southern CA Hi-Fi S"Wop Ron Veil well-known guitar amplifier Vacuum Tube Valley The 4th Annual Southern California Hi-Fi Swap will lech in the San Francisco area. He served P.D. Box 1499 be held on �ril 30, 2000, ot theH olidayInn Bueoo in the US Air Force, Philips Electronics Pork, 7000 Beoch Sivd., 8ueno Pork, CA and has ten rears experience in musical Lakeport, CA 95453 USA Includes CUrref1t high·end, vintoge, ports, Iu�, etc. intrument repair and service. Ron will be Phone: 707-263-5881 vendor Iob� $40 [8:00AM $eIup), forfy admission regular tube guitar amplifica ion expert a t FAX: 707-263-7648 [10:00 ami $5, [10:00AM.) $3. Call [9(9) 931- and contr ibuto r. · em 9686 to reserve 0 table or [714) 522·7000 /ord irec [email protected] ail: [email protected] tions. www.ups<oleoudio.com. EDITORIAL STAFF Vacuum Tube Valleyi s published quorterly Copyrig,t2000Vacuum Tube Valley" for electronic enthu$iasl1 interested in the and Big Tone" All rights re$E!rved. Charles Kittleson - Pubhher colorful post, present and future of vacuum No port of this f>\Jblicolion may be reprinted or otherwi$E! reproduced withovt written tube electronics. John Alwood - Technical Editor permission of the f>\Jblishe r. Subscription Role: US$45/4 issues 1 si Clau·$36 Eric Barbour . Senior Editor Sendcirculation ond editrorio[ 3rd Cion; Conodo/S48; Aiio/$66; Europe/$56 Ron Veil- Guitar Amp Specialist correspondence 10: US Bank Check, Credit Cords or Cash Vocuum Tube Valley David Bardes - Contributing ore accepted for payment. Editor P.D. Box 1499, Sieve Parr - ArtDirector Lakeporl, California 95453 USA Phone - (707) 263-5881 e-mail [email protected] FAX - (707) 263-7648 Julie P. Wemer - Copy Editor ISSN # 1095-4805 VACUUM TU II VA LLEY ISSUI 13 .. N N , E R V • W w r M P A U L K L P S C H An Interview with Paul Klipsch By David Bordes 02000 All Ri9ht� Reserved Paul W. Klipsch is an Ilud;o pitJnur who My mOlher bought 1n £discn designed and pToduud the Klipschorn Phonograph in 1923. When I folded-hor" wudspeaJur system which bas wenT home for vacation from Cow bun in production for ovtr 50 years. He College (New Mexico State), I also developed and produud uvtral Ot/UT noticed she had pur it in the cor­ loudsptllkusIlnd wrott doum of Ilrlicks ner. It was thl': most obnoxious and papers for audio pub/ielllions and place for it, but it sounded better societies. K[ipseh was induclld into The in the corner. Enginuring and Scimu Hall of Fame on October 16, 1997for his contributions in Later, in 1933, a fellow student acousdcJ, ballistics, and ,opbysics. This at Sranford loaned me onc of his interview was conducu'!. during the Fall 12 inch direct radiatOr speakers Voice 12 inch direct radiator, which was of 1999 with the assistllnu of Klipuh and I PUt it in an enclosure. At the sug­ capable of <l.bout 1 % efficiency, but by Company and, of courst, Paul gestion of another fellow student, I put it staff putting it in <I. horn we gOt 10% efficiency. Klipsch who at the time of the interview in a corneT. There was considerable improvement in the bass response. That was 94 years old! The earliest tweetl':f I can recall was prompted the idea of using the corner for offered by Bell Labs. It dictated the trend Whm didyou b!Come inumttd in audio? a location of speakers. in rn·eeters that they have a small My hither taught engines and boilers at Almost any speaker can be benefited by diaphngm which enables them to handle The Boiler Institute, Purduc: University. putting it in a corner. Especially in a cor­ high frequefl(;:iesor very shOT! wave He rook me down where rhe STudems ner application it becomes doubly lengths. Wc tried them all. pr.lcticed radio. I was around seven years improved. 1 have a theory yet to be From the Klipsch company Wrb Pages, f see old at the time. Audio wa5 thl': next step proven: di5tOrrion is inversely ropor­ that JOu started in tht back of n laundry up from r.ldio; me difference being ear­ tioned to efficiency. That is, ir we can businm. P/tlfSt describe tlu roolution of phones and loudspe.akers. have a spcaker of 1 % efficiency and com­ yourfoci/itits from those tarly Mp to your pare that [0 a speaker of 10% efficiency current production foci/itits. What txptrimcn in your tarly liftinflu­ the distortion will be 1/10 as great in the mud your work with sptaltm and your 10% efficient speaker. In 1946 I was invited by Sherman businm philosophy? Fairchild, who manufactured airplane How did you come to reafiu that the horn wings during the war, to New York [0 I spent several of my grammar years sptaktr was an ana you wifhed to restarch? visit his plant. While I was there I priced winding coils and transformers. Thol.( pre­ buildings [0 S12rt a small manufacturing vented me from learning how they The horn is a more efficiem way of F.tciliry. worked. reproducing sound than a direct radiator. Bell Laboratory's horns achieved 30% effi­ One offering was a 11 x 1 G foot room What influtnud your delle/opmmt of rht ciency against I % from the typical direct for $400 a month. This seemed awfully Klips(horn? radiator and 1/10% for some over-advl':r­ steep. The laundry business here in Hopt: tised direct ndiators.