Manuale d’uso / di manutenzione del prodotto VT-15 del fabbricante D.W. Fearn
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VT-15 Vacuum Tube Recording Channel Operating Instructions D.W. FEARN.
D.W. FEARN VT-15 Recording Channel Ho w to Cont act us: T elephone: 6 1 0-793-2526 F ax: 6 1 0-793- 1 479 Mail: P .O. Bo x 57 , P ocopson, P A 1 9366 U .S.A. Shipping A ddress: 1 82 Bragg Hill R oad W est Chester , P A 1 9382 U .S.A. e-mail: dwf ear n@dwf ear n.
D . W . F EARN H AND - CR AFTED PR OFESSION AL RECORDIN G EQUIPMENT www .dwfear n.com P .O. Bo x 57 P ocopson, P A 1 9366 U .S.A. T el: 6 1 0-793-2526 F ax: 6 1 0-793- 1 479 Cer tificate of RoHS Compliance D.W . F ear n is committed to manuf acturing pr oducts t hat ar e fully-com pliant wit h t he EU R oHS Dir ectiv e.
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D.W. FEARN VT-15 Recording Channel 5 VT-15 Vacuum Tube Recording Channel Final Test Report Serial Number_______________ Mains Voltage 120/240 set to __________________ Date ________________ Tested by .
D.W. FEARN VT-15 Recording Channel 7 Table of Contents R oHS Com pliance Dat a .................................................................. 3 Final T est R epor t ............................................................................ 5 W ar ranty .
D.W. FEARN VT-15 Recording Channel 8 D.W . F ear n shall not be liable f or technical or editorial er r ors or omissions in t his manual, nor f or incident al or consequential damag es r esulting fr om t he use of t his material. This instr uction manual cont ains inf or mation pr otected b y cop yright.
D.W. FEARN VT-15 Recording Channel 9 Limited 5-Year Warranty During t he w ar ranty period, D.W . F ear n will, at no additional char g e, r epair or r eplace def ectiv e par ts wit h ne w par ts.
D.W. FEARN VT-15 Recording Channel 11 History of the VT-15 Vacuum Tube Recording Channel W it h t he success of t he VT - 1/VT -2 V acuum Tube Micr ophone Pr eam plifiers, t he VT - 4 LC Equalizer , t.
D.W. FEARN VT-15 Recording Channel 12.
D.W. FEARN VT-15 Recording Channel 13 Mic Input 150 ohms Input Load Impedance 1.5k ohms Minimum Input Level -65 dBm nominal Maximum Input Level @ 20 cps -30 dBm without pad -5 dBm with 20 dB pad Instr.
D.W. FEARN VT-15 Recording Channel 14 Compression Range up to 30dB Compression method Pulse-width modulator Equalizer: Low-frequency Boost 100 cps, shelving Low-frequency Cut 80 cps, shelving High-frequency Boost 9.8 kc, peaking High-frequency Q 0.6 to 1.
D.W. FEARN VT-15 Recording Channel 15 2. DESCRIPTION The D.W . F ear n VT - 1 5 utilizes cir cuitr y de v eloped f or t he VT - 1/VT -2 V acuum Tube Micr ophone Pr eam plifiers, t he VT -7 Ster eo Com pr essor , and t he VT -4 LC Equalizer .
D.W. FEARN VT-15 Recording Channel 16.
D.W. FEARN VT-15 Recording Channel 17 3. INST ALL A TION The VT - 1 5 is car efully pack ed f or shipment and it should surviv e all but t he most br ut al han - dling. If t her e is an y damag e, k eep t he shipping material f or use during an y possible claim f or damag e wit h t he shipper .
D.W. FEARN VT-15 Recording Channel 18 t he back panel f or inst allations t hat use separate chassis gr ounding. If gr ound loop hum is detected, a car eful check of t he studio gr ounding scheme is needed. The VT - 1 5 is less suscep - tible to gr ounding pr oblems t han man y studio de vices.
D.W. FEARN VT-15 Recording Channel 19 4. OPER A TION INITIAL SET-UP IS CRITICAL for getting the best performance from your VT-15! The VT - 1 5 has tr emendous v ersatility , but wit h t hat v ersatility comes t he potential f or f or v er y un pleasant sound.
D.W. FEARN VT-15 Recording Channel 20 Control Set-up In put togg le switches: Mic/Line switch - as appr opriate f or t he sour ce 0/-20 switch - 0 1 50/Lo-Z switch - 1 50 (unless y ou ar e using a non.
D.W. FEARN VT-15 Recording Channel 21 6. A djust t he Eq contr ols f or t he desir ed sound. (R emember to use t he Boost and Cut tog et h- er to shape t he sound.) 7 . Switch t he VU meter back to t he VU position. 8. A djust t he Gain contr ol f or a nor mal indication.
D.W. FEARN VT-15 Recording Channel 22 C ONTR OLS (see Figure 1 .) The VT - 1 5 fr ont panel is divided into t hr ee main ar eas of contr ols. On t he left is t he In put sec - tion, to its right is t he Com pr essor section, fur t her right is t he Equalizer section, and f ar right is t he output and po w er section.
D.W. FEARN VT-15 Recording Channel 23 es t he polarity of t he output of t he VT - 1 5. A det ailed discussion of t he application of phase re v ersal of individual micr ophones is be y ond t he scope of t his manual.
D.W. FEARN VT-15 Recording Channel 24 add distor tion to lo w fr equency sounds. (This is tr ue of all com pr essors.) A f ast r elease time adds density to t he sound, often wit h t he com pr ession becoming mor e obvious.
D.W. FEARN VT-15 Recording Channel 25 should r esult in “0 VU” on a pr operly aligned r ecor der . (This r ef er ence le v el can be chang ed; see t he Maintenance Section.) This is a tr ue VU meter , and conf or ms to AS A St andar d C1 6.5- 1 954.
D.W. FEARN VT-15 Recording Channel 26 1 . Use t he best quality mic cable y ou can. W e don’t belie v e y ou ha v e to use esoteric wir e, but do use a good cable designed f or lo w im pedance micr ophones. A quality cable wit h gold-cont act connectors is best.
D.W. FEARN VT-15 Recording Channel 27 5. THEOR Y OF OPER A TION Preamp Section Input section Micr ophone le v el (1 50 ohm sour ce im pedance, balanced, -50 dBm nominal) or line le v el (600-ohm sour ce, +4dBm nominal) audio enters t hr ough t he XLR-3 f emale INPUT connec - tor to t he In put selector switch bank.
D.W. FEARN VT-15 Recording Channel 28 r esponse, lo w phase shift, ex cellent squar e w av e r esponse, lo w distor tion, and high noise immunity . The secondar y of is connected dir ectly to t he grid of t he first am plifier st ag e.
D.W. FEARN VT-15 Recording Channel 29 VU Meter and Meter Amplifier A tw o-st ag e IC operational am plifier is used to isolate t he VU meter fr om t he VT - 1 5 output. An output sam ple is deriv ed fr om t he primar y of t he output transf or mer . The meter calibra - tion is set wit h a 20-tur n trimmer potentiometer .
D.W. FEARN VT-15 Recording Channel 30.
D.W. FEARN VT-15 Recording Channel 31 6. MAINTENANCE The VT - 1 5 is built wit h only t he highest quality par ts and will pr o v e to be extr emely r eliable. V acuum tubes and electr olytic capacitors, ho w ev er , ha v e a finite useful lif e and must be r eplaced e v entually .
D.W. FEARN VT-15 Recording Channel 32 Tubes also sometimes de v elop a micr ophonic r esponse — t he y will r espond to ambient noise and vibration. This can be an insidious pr oblem since measur ements in a quiet r oom will indi - cate per f ect per f or mance.
D.W. FEARN VT-15 Recording Channel 33 Troubleshooting Most pr oblems will be traced to def ectiv e v acuum tubes. Ho w e v er , if nor mal tests do not eas - ily r e v eal t he pr oblem, f eel fr ee to call t he f actor y f or assist ance.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il D.W. Fearn VT-15 è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del D.W. Fearn VT-15 - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso D.W. Fearn VT-15 imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul D.W. Fearn VT-15 ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il D.W. Fearn VT-15, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del D.W. Fearn VT-15.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il D.W. Fearn VT-15. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo D.W. Fearn VT-15 insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
