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Although  spaced  microphones  can  produce  similar  stereophonic  results,  such  recordings when 
summed to mono can suffer from “comb filter”  effects: peaks and dips in the frequency response. 
When the SF-24V  is used for M-S recording,  the  feeling of space  changes but the  sonic quality 
does  not.  For  more  detailed  information  on  the  M-S  technique,  see  the  chapter  Recording 
Techniques: Mid-Side (M-S) Recording in this manual.

Ribbons in the Digital World

Digital recordings benefit greatly from the properties inherent in ribbon microphones. Since A to 
D  converters  cannot  distinguish  between  the  sound  source  being  recorded  and  the  complex 
distortion  components  often  associated  with  condenser  microphones,  they  sometimes  have 
difficulty  tracking  the  signal,  resulting  in  ringing  and  edgy-sounding  tracks.  With  ribbon 
microphones,  ringing  is  almost  nonexistent  due  to the  ribbon’s  lack  of  distortion  artifacts  and 
high frequency peaks. A to D converters have less difficulty tracking the ribbon generated signal, 
resulting in very smooth digital recordings free of microphone-related edginess.

User Guide

Using the SF-24V Vacuum Tube Stereo Ribbon Microphone

The  head amplification  system  utilized in the  SF-24V consists of two independently configured 
military grade vacuum tube buffering circuits. Power for the tubes is supplied to the microphone 
from a dedicated AC-line operated power supply that connects to the microphone through a 7-pin 
microphone  cable.  The  power  supply  provides  a  high  voltage  source  and  independent  low 
voltage  sources  for  the  vacuum  tube's  filaments.  An  electronic  constant  current  source 
automatically  compensates  for  any  change  in  the  microphone's cable's length and  provides  the 
correct voltage and current to each of the vacuum tube's heaters.

1. Always  connect  the  microphone  to  the  power  supply  before  applying  AC  or  turning  the 

supply on. Allow  at least  ten minutes of warm up time before using the microphone. This is 
required to give ample time for the vacuum tubes elements to "settle."

2. The  stereo  outputs  of  the  SF-24V  are available  at  the  power  supply  through a  pair  of  male 

XLR  connectors.  OUTPUT  1  corresponds  to  the  upper  transducer  and  OUTPUT  2 
corresponds  to  the  lower  transducer  when  the  mic  is  held  vertically.  Each  output  is 
transformer  isolated  and  fully  balanced.  The  SF-24V’s output  configuration  is  as  follows: 
Pin-1 is a shared ground for each output  connector; Pin-2 is signal hot  (in-phase) and Pin-3 
signal cold (reverse-phase).

3. In rare instances, the  common ground connection (Pin-1) between the two output connectors 

can cause a ground loop. This can occur when poorly designed preamplifiers or certain types 
of patch bays and/or wiring configurations are  encountered. If this condition presents itself, 

5

Summary of Contents for SF-24V

Page 1: ...Royer Labs Model SF 24V Vacuum Tube Stereo Ribbon Velocity Microphone Operation Instructions Manual User Guide Made in U S A ...

Page 2: ... 8 Connecting the SF 24 8 Power Supply Input Module 9 Fuse Replacement 9 Voltage Changeover 9 Amplification Considerations 10 Stereo Microphones and Ground Loops 11 Equalization and Ribbon Microphones 12 Hum Noise and Mic Orientation 12 Microphone Techniques 13 General Tips for Using the Royer SF 24V 13 Specialized Stereo Recording Techniques 16 Classic Blumlein Technique 16 Mid Side M S Technique...

Page 3: ... this microphone Royer Labs products are manufactured to the highest industrial standards using only the finest materials obtainable Your model SF 24V went though extensive quality control checks before leaving the factory Normal care is all that is required to assure a lifetime of trouble free service Please read this manual thoroughly in order to become familiar with all of the SF 24V s capabili...

Page 4: ...d by the ROYER logo If however the microphone is suspended upside down the connections to the preamplifier should be reversed since what was the left transducer is now responding to signals from the right and vice versa Your SF 24V is supplied with a dedicated power supply and 7 pin microphone interface cable The output for each channel consists of a chassis mounted 3 pin male XLR connector These ...

Page 5: ...ffering circuits Power for the tubes is supplied to the microphone from a dedicated AC line operated power supply that connects to the microphone through a 7 pin microphone cable The power supply provides a high voltage source and independent low voltage sources for the vacuum tube s filaments An electronic constant current source automatically compensates for any change in the microphone s cable ...

Page 6: ...roximately the same distance used for cardioid microphones This method is used to achieve the same ratio of direct to reflected sound 2 In the horizontal plane ribbon microphones do not discriminate against the highs off axis nor do they boost them on axis Therefore several instruments or vocalists can be placed in front of the microphone without favoring the performer in the center of the group S...

Page 7: ... with minimal pressure There is also a relief button that enables the clutch handle to be repositioned out of the way The shock mount has two orientation slots for easy X Y and M S positioning The X Y slot faces forward and the M S slot is 45º to the left Usage It is important to use the RSM 24 shock mount correctly Making sure that the microphone is inserted properly into the shock mount will min...

Page 8: ...ements are sensitive to abrupt shocks and blasts of air so be gentle Note If after a time body oils or other contaminants make it difficult to insert or remove the microphone from the shock mount a small amount of talc can be used to lubricate the microphone housing Use talc very sparingly and do not let any of it get into the ribbon transducers as it can compromise the ribbons performance Connect...

Page 9: ...tly pry the door open Image 3 Be careful not to damage the painted surface of the chassis housing The fuses are located inside two carriers each marked with an arrow pointing to the right These carriers can be pulled out with the tip of a screwdriver blade or a pair of needle nose pliers Image 4 Once the carriers are removed the fuses can be pulled out with your fingers Replacing the fuse carriers...

Page 10: ...utput allows for long cable runs with minimal affect on the microphone s performance High frequency response losses and noise pickup will be minimal even with cable runs up to several hundred feet in length NOTE There are no user serviceable parts in the power supply or microphone Leave all servicing of your SF 24V to a qualified technician authorized to service this product Amplification Consider...

Page 11: ...ics would reach an overload condition Due to the high output potential of the SF 24V it is recommended that the microphone preamplifier you pair it with have a switchable pad to prevent the possibility of overloading the preamplifier s input stage electronics Some preamplifiers are more thoughtfully designed than others with a suitable pad that is placed before the preamp s active electronics not ...

Page 12: ...ibility The reason that ribbon mics take EQ so well is their inherent low self noise unusually smooth frequency response characteristics and freedom from off axis coloration Dialing in high amounts of equalization on condenser or dynamic microphones also means dialing in extra amounts of the microphone s distortion products and self noise garbage that contributes to an unnatural unpleasant sound B...

Page 13: ...ponding lower level and hence less likely to be objectionable Microphone Techniques General Tips for Using the Royer SF 24V The following are good basic starting places for recording with the SF 24V These positions are known to produce good results but experimentation is the key to getting the most out of your recordings Photographs of many of the following techniques can be found on our website w...

Page 14: ...um tracks where cymbals need to sizzle you can brighten them by adding a few dB of 10K to 12K Brass Brass records beautifully with ribbon microphones For an overall picture of a brass section within a larger recording session try placing the microphone at a distance of three to eight feet from the section two to three feet above the instrumentalists and angled downward For a solo brass section pos...

Page 15: ...ou are there realism The rear lobes of the figure 8 elements bring the ambient qualities of the recording environment into the recording adding to the natural feel of the recorded performance Percussion The SF 24V records percussion instruments naturally without upper frequency hype or low end boominess Congas bongos and the like can be recorded with left right stereo effect by positioning the mic...

Page 16: ... can be summed to mono with no comb filter effects and room reverberation undesirable in mono is cancelled to a surprising degree For the sake of clarity engineers commonly refer to similar stereo miking with cardioid mics as X Y When figure 8 s are used it is more commonly referred to as Blumlein recording Mid Side M S Technique In the early days of stereo radio broadcasting the Mid Side recordin...

Page 17: ...ement turned all the way down you have just the mid element panned center and giving a mono pickup If the outputs of the mid and side elements are recorded on separate tracks the electrical connections shown in Figure 3 can be made at the mixer outputs and the adjustment of the stereo separation can be done during mixdown rather than during the actual recording Space does not permit a fuller discu...

Page 18: ...A small amount of denatured alcohol can be used to remove fingerprints and other stains Use WD 40 or mineral oil to protect the finish 6 Keep metal filings away from the microphone at all times The SF 24V s powerful magnets can attract minute ferrous particles into the ribbon transducers compromising the performance 7 When not in use store the microphone in its protective carrying case If the micr...

Page 19: ... sparingly and apply with a soft cloth Paste wax may also be used for a high luster finish CAUTION Due to the transducer s powerful magnets keep recorded tapes spring wound watches and personal credit cards with magnetic coding away from the microphone to prevent possible damage Features Excellent stereo imaging and separation in one microphone Smooth wide frequency response Vacuum Tube electronic...

Page 20: ...ure with wire leads Output Connectors Two 3 Pin Male XLR connectors Power Requirements 110 120 220 240 volts AC 50 60HZ see manual Mic Dimensions 270mm X 39mm base X 25mm top 10 5 8 X 1 5 wide base X 1 wide top Microphone Weight 572 grams 20 2 ounces Shipping Weight 21 LBS Finish Dull Satin Nickel Optional finishes Optical Black Chrome and 18K Gold Accessories Camera style carrying case dedicated ...

Page 21: ...Polar Pattern Frequency Response 21 ...

Page 22: ...Wiring Diagram 22 ...

Page 23: ... date of original purchase and for the respective periods specified above Royer Labs agrees to repair at its sole expense all Royer Labs products which are defective in material and workmanship EXCLUSIONS This warranty does not cover the following 1 Defects or damage caused by accident fire flood lightning or other acts of nature 2 Defects or damage caused by abuse misuse negligence or failure to ...

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