Vadlyd md12 mk4 78 rpm and riaa record preamplifier jørgen vad lydteknik - farum gydevej 65 - dk 3520 farum - denmark - phone: +45 45806425.
Table of contents important safety instructions ..........................................................................................3 environment ...............................................................................................................................3 a note from the man...
Important safety instructions • set the voltage selector switch on the rear panel to 230 v ac or 115 v ac (50-60 hz) prior to use. • never operate this switch while connected to power mains!!! • this equipment requires a grounded outlet and a polarized or grounding type iec power cord suitable for y...
A note from the manufacturer recording engineers and serious record collectors know the problem when playing early phonograph re- cords: ordinary riaa phono equalization does not always match the original recording equalization that was used to make the record. 78rpmrecordsinparticularhavemanydiffer...
About phono preamplifiers whenplayingphonographrecords,youmightnormallyusethephonoinputprovidedonyouramplifier, often called a riaa (recording industries association in america) phono input. Theriaaequalizationcurvespecifiestwoturnoverpoints(a‘turnover’pointiswherethelevelchanges ±3db):oneat500hz,an...
Boosting the treble during recording had the effect of reducing the surface noise during playback. It was alsocommontoflattenoutthebassattheverylowestfrequenciestoreducetheboostofrumblefromthe turntable. Similartechniqueswereappliedtomicrogrooverecords,andthefinalstandard,riaa,providesfor abassboost...
Stylus selection atthetimetheformatdisappearedasapopularformat,therecommendedstylussizewas60μ(0.0025”) conicaltip.Thiswouldbesatisfactoryforrecordsmadeinthefinalfewyears,butforthegreatmajorityof thetimesincethebeginningof78sin1896thegroovesweremuchwiderthanthe’standard’,withtheresult thata60μstyluss...
Speed selection notall78swereactuallyrecordedat78rpm.Eveninthelate1920s,englishcolumbiawasstillusing80 rpm,andpriortoabout1921speedswerewidelyvariable.Speedsaslowas68orashighas84rpmare not uncommon. Tomakemattersworse,relativelyfew78rpmrecordsstatethespeed(andwhentheydoit’snotalways accurate).Ifthew...
Rear panel (left to right) • ac power connector with fuse. 90 - 260 v ac. • ground lift switch. • firstsetofoutputs(lefttoright)arebalancedxlrswithpin1ground,pin2hot,andpin3cold.Profes- sional users will be familiar with this. Eq is applied to these outputs. • second set of outputs are rca phono jac...
Setting the correct equalization using the presets coarse groove (78 rpm) system treble t/o bass t/o lower bass t/o cut at 10 khz boost at 50 hz flat flat flat us mid 30 flat 400 hz 70 hz 16 db westrex flat 200 hz 15 db hmw flat 250 hz 50 hz 12 db ffrr 1949 6.36 khz 250 hz 40 hz 5 db 12 db early dec...
Microgroove (lps and 45 rpm) system treble t/o bass t/o lower bass t/o cut at 10 khz boost at 50 hz ffrr lp 1953 3 .00khz 450 hz 100 hz 11 db 12.5 db ccir 3.18 khz 500 hz 50 hz 10.5 db 17 db nab 1.60 khz 500 hz 16 db 16 db riaa 2.125 khz 500 hz 50 hz 13.6 db 17 db use ffrr lp 1953 for early decca lp...
Specifications power requirements: 90 - 260 v ac frequency response: 18 hz to 54 khz (-1 db) inputimpedance:47kohm/47pf(mm),50/100/200ohm(mc) gain@1khz:50db(mm),75db(mc) max out: +24 dbu output impedance (normal out) 50 ohm load impedance (normal out): > 600 ohm deviation from riaa-curve: max. 0.5 d...
