Summary of Contents for VADLYD MD12
- Page 1 VADLYD MD12 78 RPM and RIAA Record Preamplifier Jørgen Vad Lydteknik - Farum Gydevej 65 - DK 3520 Farum - Denmark - Phone: +45 45806425...
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Page 2: Table Of Contents
TABLE OF CONTENTS IMPORTANT SAFETY INSTRUCTIONS ..................3 ENVIRONMENT ..........................3 A NOTE FROM THE MANUFACTURER ..................4 ABOUT PHONO PREAMPLIFIERS ....................5 EQUALIZATION OF PHONOGRAPH RECORDS ................5 STYLUS SELECTION ........................7 SPEED SELECTION ........................8 HOW TO USE THE PREAMPLIFIER: Front Panel ............................8 Rear Panel ............................9 SETTING THE CORRECT EQUALIZATION - USING THE PRESETS .........10 REPRODUCTION OF PATHÉ... -
Page 3: Important Safety Instructions
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 your area. -
Page 4: A Note From The Manufacturer
A few words concerning long life of all electronic equipment: most potentiometers can stand severe wear for decades, but dust - and especially smoke - can make them noisy in a very short time. Tobacco smoke is ALMOST as dangerous for a pot as it is for your health! I wish you good luck with your purchasing of the VADLYD MD12 MK4, and I hope to hear about your expe- riences with it. Farum, Denmark, July 18, 2014 Jørgen Vad VADLYD Mastering & Audio Restoration Page 4... -
Page 5: About Phono Preamplifiers
ABOUT PHONO PREAMPLIFIERS When playing phonograph records, you might normally use the phono input provided on your amplifier, often called a RIAA (Recording Industries Association in America) phono input. The RIAA equalization curve specifies two turnover points (a ‘turnover’ point is where the level changes ±3dB): one at 500Hz, and the other at 2125Hz. The RIAA playback curve has the following theoretical response: 1. +17dB from 20Hz to 50Hz, then falling about 6dB/octave to 2. 0dB from 500Hz to 2125Hz, and then falling again about 6dB/octave to 3. -13.7dB at 10kHz. You use the RIAA playback curve to compensate for the RIAA equalization that was originally used to make the record. - Page 6 Boosting the treble during recording had the effect of reducing the surface noise during playback. It was also common to flatten out the bass at the very lowest frequencies to reduce the boost of rumble from the turntable. Similar techniques were applied to microgroove records, and the final standard, RIAA, provides for a bass boost below 500 Hz and a treble cut above the lower frequency of 2,212 kHz - the latter reflecting the considerably increased amount of treble which can be cut onto an LP. Therefore playing a 78rpm record using RIAA equalization - all that is available to many people - produces far less top end response than is correct, particularly for the earliest electrical records, where the result is akin to turning the treble control down. (Turning the treble up gives an improvement, but it doesn’t touch the important mid-range.)
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Page 7: Stylus Selection
STYLUS SELECTION At the time the format disappeared as a popular format, the recommended stylus size was 60μ (0.0025”) conical tip. This would be satisfactory for records made in the final few years, but for the great majority of the time since the beginning of 78s in 1896 the grooves were much wider than the ’standard’, with the result that a 60μ stylus skates about in the bottom of the groove, seriously increasing the surface noise. The basic stylus is conical, with a spherical tip; the included angle of the cone is 60 degrees. Most modern styli are elliptical: i.e. they look the same from the front, but from the side they have a much narrower angle. This enables them to track movements in the groove more easily (as the groove moves from side to side it effectively narrows - not across its direct width but across the diameter of the conical tip, at an angle to the direction of travel: consequently a spherical tip will ride up in the groove). The illustrations below could apply equally to a spherical tip and an elliptical tip seen from the front: in prac- tice I would always recommend elliptical. -
Page 8: Speed Selection
3. Pressing only the third button enables you to hear Right Channel (outer groovewall) alone in both speakers. 4. Pressing both the second and third buttons together lets you hear both groovewalls in mono. 5. With neither the second or third buttons pressed, the Vadlyd MD12 Mk2 is working in normal ste- reo mode. • Next is the volume control for the XLR flat outputs, the main volume control, the stereo balance control, the headphone volume control, the stereo headphone jack, and the power on/off switch. -
Page 9: Rear Panel
Rear Panel (left to right) • AC power connector with fuse. 90 - 260 V AC. • Ground lift switch. • First set of outputs (left to right) are balanced XLRs with pin 1 ground, pin 2 hot, and pin 3 cold. Profes- sional users will be familiar with this. Eq is applied to these outputs. • Second set of outputs are RCA phono jacks for connecting to consumer equipment. These outputs are unbalanced. -
Page 10: Setting The Correct Equalization Using The Presets
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... -
Page 11: Reproduction Of Pathé And Edison Records
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 1.60 kHz... -
Page 12: Specifications
0 dBu = 0.775 V Balanced XLR’s: Pin 1 = ground, pin 2 = hot, pin 3 = cold. Limited Warranty VADLYD MD12 MK4 is warranted for two years from date of purchase to be free of defects in materials and workmanship. In event of such defect, VADLYD MD12 MK4 will be repaired promptly without charge. This warranty excludes defects due to normal wear, abuse, shipping damage, or failure to use product in accordance with instructions. This warranty is void in the event of unau- thorized repair or modification, or removal or defacing of the product labelling. For return approval...