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4/19/2011 For additional information, please visit the Bybee web site at www.BybeeLabs.com QUICK START GUIDE with HIGH-VOLTAGE INFORMATION 4 Pages INSTRUCTIONS FOR THE 2AMP Music Rail™ and the 15AMP Music Rail™. Performance data, power supply information, installation and mounting notes and high-voltage information. 1 See high-voltage schematic on high-voltage information below See app note J0409 for exceptions, Bypass Capacitors 3 See app note J0310 for exceptions, Tube Amp Applications 4 See app note J0308 for exceptions, DAC Applications 5 15A Music Rails require heat sinks and insulators 6 Actual output noise will be input noise after suppression, or noise floor, whichever is greater 2 Fig. 1. Pin-Out Guide 4/18/2011 MUSIC RAIL™ INSERTS HERE Fig. 2. Simplified DC power supply Read: 0.5V drop for 2A devices. Read: 2.1V drop for 15A devices. MUSIC RAIL™ Fig. 3. Music Rail modified power supply MUSIC RAIL Installation Notes 1. Vin must supply 11.5mA idle current to the Music Rail circuit (plus an additional 5mA to ZD1 when a high-voltage adaptor is used). 2. J1 is the AC ground that bypasses noise currents and input ripple to ground. 3. J12 is the DC ground that returns idle current to the input source. 4. J1 and J12 may be tied together or run separately to optimize noise floor (experimentally). 5. J2-J6 (Vin) can carry 3A each and should be ganged together to carry higher currents. 6. J7-J11 (Vout) can carry 3A each and should be ganged together to carry higher currents. 7. 15A Music Rails must use appropriate heat sink (Pd=2.1V* load current). 8. Transistor on 15A Music Rails must be isolated from ground with thermal insulator. 9. Output capacitor not recommended (see app note J0409: Bypass Capacitors). 10. After installing each unit, insure that correct voltage drop appears from input to output (0.5V for 2A modules, 2.1V for 15A modules). See data sheet for additional test data. MUSIC RAIL™ Quick Start Guide Page 2 4/18/2011 11. When negative polarity modules are used above 30V, the zener clamps in the hi-voltage adapter must be reversed. All other connections remain the same. 12. As a final test, ensure that the output noise is lower than the input noise (if not, see FAQ). MUSIC RAIL Mounting Notes 1. 2. 3. 4. 5. 6. 7. 8. Try to locate the high-voltage adapter parts within 6” of the associated Music Rail. Try to locate each Music Rail within 12” of the stage it feeds. Power resistors in high-voltage adaptors should be derated 5-7 times and should be at least 10mm distance from noise cap. Leave resistor leads 10-20mm long for increased cooling. The Music Rails can be bypassed for demonstration purposes. Simply jumper the input to the output. Wire guage must be appropriate for load current. For coplanar PC board mounting, a set screw can be used to mount each module to an existing board standoff. The mounting collar in each module is isolated and can be mounted directly to the chassis. The mounting collar accepts #4 screws, but can be drilled out to accept 6-32 screws if required. Mounting screw heads and standoffs should be 0.25 diameter max. Do not exceed mounting pad diameter unless nylon or fiber washers are used for isolation. 15A modules can be mounted to existing heat sinks. Simply drill and tap into the heat sink. Use caution. Taps are hard and brittle. Take care not to over twist the tap. MUSIC RAIL™ HIGH-VOLTAGE INFORMATION All Music Rail applications above 30V require High-Voltage Adaptation. YOU WILL NEED: 1. One or more resistors optimized for your app. (See selection chart on app note J0413). 2. Two 24V, 1W zener diodes (high-voltage clamps). For negative supplies, D1 and D2 must be reversed. 3. One 1uF capacitor (noise drain). For a list of recommended parts and suggested suppliers, please see app note J0412. 4. Two terminal strips for mounting parts. (See Mounting Instructions above). MUSIC RAIL™ Quick Start Guide Page 3 4/18/2011 *R1 = (Vin-24V) / (.005A + .0115A) = (D1 + Music Rail Current *W = (Vin-24V) X (.005A + .0115A) X 5 (5X derating factor) Fig. 4. Bybee High-Voltage Power Supply Photos showing typical layouts Diode location on PC board High-voltage parts mounted & wired. ## MUSIC RAILS are manufactured in the United States. 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] MUSIC RAIL™ Quick Start Guide Page 4 Bybee MUSIC RAILTM Direct Current Power Conditioners General Description Applications High-Fidelity Analog Components High-Fidelity Digital Components High-Definition Video Components Test & Measurement Equipment Linear Power Supplies Switching Power Supplies High-End Car Stereo Medical Equipment Any other applications where power supply noise & signal-on-rail affects equipment performance The Bybee Music RailsTM from Bybee Labs are small footprint, active DC power conditioning modules. They are designed to be installed at the terminus of DC linear & switching power supplies. With their low noise and low impedance, they produce a highly purified source of DC power for any load within their ratings. Signal-on-rail is reduced along with power supply noise. (See noise chart, page 3). There are two models available in two polarities: 2A +/- and 15A +/-. Only 0.5V is dropped by the 2A device and 2.1V by the 15A device. Any model can be used to clean up the noise floor of switching power supplies to levels representative of the very best analog supplies. In linear supplies, large banks of filter capacitors can be replaced by simple ripple filters, allowing package size to be reduced. Features Low Noise Floor: 20nV/root(Hz) Low Output Impedance: 6mΩ typ Wide Voltage Range: 4.5–550V High Current Range: 0-2A / 0-15A Low Dropout Voltage: 0.5V / 2.1V Low Dissipation: 1W / 31.5W Direct-Coupled Topology Small Footprint: 1.7H x 1.5W x 0.4D Fig. 1 Raw DC Power Supply Fig. 2 Raw Supply + DCPC Benefits In Fig. 2 (above), a MUSIC RAIL module is inserted between the raw power supply and the active circuit. The module now interfaces direct with the active circuit. Signals from circuit stages that share common power supply rails are bypassed by the wideband, low impedance of the MUSIC RAIL. The DC current coming out of the raw supply is at the same time highly filtered by the Module. This dual effect improves the definition of both audio and video signals. The MUSIC RAIL operates safely up to 30V and is adaptable to high-voltage power supplies by the addition of three external parts. See Fig. 5 (below) for high-voltage schematic and page 3 for R1 derating chart. 1 Performance Characteristics Fig. 3. Dimensions Installation Notes 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. J1 bypasses noise currents & input ripple to ground. Vin must supply 11.5mA idle current to the Music Rail circuitry. J12 returns the Music Rail idle current to the input source. J1 & J12 may be tied together or run separately to star. J2-J6 (Vin) should be ganged together to carry more current. J7-J11 (Vout) should be ganged together to carry more current. 15A devices must use appropriate heat sink (Pd = 2.1V * load current). 15A device transistor must be isolated from ground with thermally conductive insulator. Output capacitor not recommended (see app notes). C1 must withstand the full input voltage with headroom for line surges. Fig. 5. Bybee High-Voltage Power Supply Fig. 4. Hook-up Guide Fig. 6. Bybee High-Voltage Power Supply Typical Test Voltages *R1 = (Vin – 24V) / (.005A + .0115A) = (D1 + Music Rail current) *W = (Vin – 24V) X (.005A + .0115A) X 5 (formula 5X derating factor) Positive polarity shown. Zener must be reversed for negative Music Rails. 2 Noise Suppression vs Frequency Resistance vs Input Voltage, 30V to 150V Resistance vs Input Voltage, 150 to 550V 3 Bybee MUSIC RAILSTM Hi-Voltage Adaptation If your project is high-voltage, above 30V, and you need help, e-mail or call us. [email protected] 480-998-2880 Or download information from the “Product” section at the Bybee Labs web site. For high-voltage adaptation you will need: 1. One or more 20W resistors optimized. 2. Two 24V, 1W zener diodes (high voltage clamps). 3. One 1uF, 630V polypropylene capacitor (noise drain). 4. Two terminal strips for mounting parts. 5. A schematic showing value(s) of R1 (Fig. 5) on page 2. 6. Photographs showing typical layouts. (Fig. 7) (Fig. 8) Fig. 7. Diode location on PC board. Fig. 8. High-voltage parts mounted & wired. Bybee Labs, Inc. Information and Ordering Bybee MUSIC RAIL TM Doug Hall 1-480-998-2880 | 1-480-907-2894 Fax [email protected] 8390 East Via de Ventura F-110 Scottsdale, AZ 85258 Music Rail In – Noise Out! www.BybeeLabs.com © 2010 - 2011 Bybee Labs, Inc., Scottsdale, AZ 85258 4 BYBEE MUSIC RAIL™ White Paper What are they? How do they work? Why do I need them? We hear these questions all the time. The short answer is: Bybee Music Rails actively increase the resolution and definition of both audio and video signals by removing noise and unwanted signal from DC power supplies. This paper will explain conceptually the function and purpose of the new, active-circuit Music Rail™. I. The Vibrating String Analogy You probably think this section is going to create a tie-in to quantum string theory. Not exactly. Remember the talking string we used to play with as kids? The one with a tin can attached at each end? One person speaks into the first can while the other person listens into the second one. The vocalized air in the first can causes the string to vibrate. This in turn causes the second can to move air into the ear of the listener. So far everything is clear. Now imagine that a sandstorm blows up. The sand impacts the cans as well as the string. There is now a granular surf noise constantly impacting everything that is spoken or heard. This granular noise alters the vibrations of the string in unpredictable ways. This noise is analogous to power supply noise in audio systems. II. The Niagra Falls Analogy Imagine a sheet of crystal clear water falling over a glass wall. You can see right through the water, through the wall, and into the next room. In that room are rows of flower pots. All kinds of flowers in many colors. You can see all the details of the flowers. The colors, the petals, the pistils, the pollen–every detail is crystal clear. Now imagine that there is a box of sand at the top of the waterfall that begins slowly sifting into the falling water. The sandy water will degrade the pattern of the floral details in unpredictable ways. This granular sheet of sand is analogous to power supply noise in video systems. III. The Rusty Pipes Analogy Imagine a thin stream of pure water flowing smoothly out of a faucet. The stream is clear, calm, and continuous. We can see right through it. Now imagine that the pipes are rusty and that the water has become tinted by a brownish muck. Tiny specs of rust cause the water to fizz and flicker. Everything we look at through the water now takes on a fuzzy, brownish tint. When we install a charcoal filter in line with the pipe, the water turns clear again. This filter is analogous to the effect of a Bybee Music Rail. 1 of 3 IV. Vibrating Strings Again Before explaining what actually happens in the power supply of an audio amplifier, we must first string these analogies together. It has been shown mathematically by many practitioners over many decades that electric current is analogous to flowing water and vibrating strings. Let's now combine the two concepts of the vibrating string and the water faucet. Imagine a thin stream of pure water flowing smoothly out of a faucet. The stream is clear, calm, and continuous. We can see right through it. Now imagine that a piano string has been pulled tightly from one end of the stream to the other. The piano string runs right down the middle of the stream, affecting all of it. A tap on the piano string makes it vibrate. This in turn causes the stream to vibrate. If there is rust or sand in the water, the audio vibrations will intermix with them in unpredictable ways, causing distortion. The sound is then no longer pure and transparent. It is polluted by noise. In an audio amplifier, the stream of water is replaced by a stream of electrons. The electron stream originates in the power supply. There is no piano string, but the effect is the same. The audio signal (music or voice vibrations in electrical form) enters the electron stream through tubes or transistors, which act as gates. The audio signal causes the electron stream to “vibrate” (the stream is actually modulated by the signal, and forced to conform to the pattern of the signal). So far all is well, but what happens if the electron stream is impure? You can be sure that it is. V. The Electron Stream The power supply electron stream originates from the wall socket (long before that, but let's start there for now). The electron stream from the wall is a polluted sine wave (AC + noise). A sine wave looks in many ways like a rope that has been yanked at one end. When it jumps, the rope ripples from one end to the other. This ripple, in electronic form, is what actually enters the power supply from the wall socket. The first task of the power supply is to smooth out the ripples in the electron stream. We want the electron stream to behave like “pure water flowing smoothly out of the faucet.” That way, when the audio signal enters the stream through tubes or transistors, there will be no interference by the ripples. We want the stream to remain clear, calm, and continuous, so we can hear right through it to the music. This is critical, because if there is any kind of noise on the power supply rails, that noise will intermix with the audio, distorting it in unpredictable ways. Noise on the rails can appear in many forms: it can be ripple; emi; rfi; unwanted audio signal; etc. All of these noise sources can degrade the audio signal. VI. Getting the Noise Out Lets the Music In There are many ways to block, filter, suppress, and bypass noise from the power supply rails. The question is, which way is best? The standard method is to use large banks of filter capacitors to bypass noise around the rails. Capacitors, however, quickly consume space. Electrically they are far from ideal. The Music Rail is designed to replace excess filter capacitors. It performs the same function as filter caps, but it does so actively, efficiently, and in far less space. The Music Rail can also improve the performance of voltage regulators. Regulators operate by locking down the rail voltage at some specific value. In so doing, the regulator samples the output voltage and compares it to a reference voltage. If there is a difference, the output voltage is pulled back to the reference voltage. The reference voltage is most often provided by a zener diode, which is itself a source of noise. The zener flickers constantly and emits a stream of low-level noise that interferes with the sampling process. The net result is that the electron stream exiting the regulator can be jumpy. The Music Rail will smooth out this jumpiness. Switching power supplies behave similarly, but are worse, because the electron stream is polluted with high-frequency switching spikes. The Music Rail can smooth out switching power supplies to levels representative of the very best analog 2 of 3 supplies. This is readily measured: up to 45dB of power supply noise is eliminated (depending on the level of input noise–see Datasheet for performance data and installation instructions). VII. How it Works in a Nutshell When a Bybee Music Rail is installed in any kind of DC power supply, the electron stream passes through it. Power supply noise is then actively filtered out of the electron stream and returned to the wall socket (earth). The electron stream itself, however, is barely affected. The Music Rail drops only 0.5V for any load up to 2A, and drops only 2.1V for any load up to 15A. The electron stream enters the Music Rail in polluted form, and exits as a pure stream of clarified current, ready to be modulated at high resolution by the music signal. ### December 28, 2010 Scott Frankland, Senior Development Engineer Jack Bybee, Senior Research Physicist CONTACT: Doug Hall 480-998-2880 / 480-213-1450 Cell [email protected] © 2010-2011 Bybee Labs, Inc. 8390 East Via de Ventura, F-110 Scottsdale, AZ 85258 3 of 3 FAQ For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ Frequently Asked Questions 4 Pages Three Most Common MUSIC RAIL™ Questions Q: What are they? How do they work? Why do I need them? A: Download the White Paper from this web site to get the full story. Other helpful information is also available in the Apps & Data section. Q: I’ve read the White Paper. (Helpful reviews are also available on this web site.) How can I confirm the performance of these devices for myself? A: There are two ways: by ear or by instrument. It is possible to strap the device from input to output, effectively bypassing it. The strap can be opened via connector or switch. By this means, the Music Rail can be auditioned in and out of the circuit. To test the device, see Testing & Troubleshooting (below). Q: I’m sold. Where can I find installation information? A: All installation information, including the datasheet, app notes, and layout examples, is available in the Apps & Data section of this site. We recommend starting with the Data Sheet and the installation guidelines. Download the Technical Data followed by App J0331: Installation & Mounting Notes. Installation Q: I have downloaded the Technical Data Sheet and the Installation Notes, but there is too much information. I just want to get started right away. What do I do? A: Download the Quick-Start Guide. Q: I have downloaded the Quick-Start Guide but I'm still confused about some installation details. What do I do? A: Keep reading. Q: My voltage rail is above 30V, so I need a high-voltage adaptor. How do I select R1 without doing math? A: Download app note J0413: R1/R2 Selection Chart. Q: How do I rate C1, the noise drain capacitor? A: The C1 voltage rating should be the same or higher than the rail voltage. More . . . Q: I have selected R1 & C1 for my high-voltage adaptor. Where can I buy these parts? A: Download App J0412: Parts, Suppliers, & Accessories. Q: My voltage rail is above 300V, so I need to use both R1 and R2, but I don't have room for two large power resistors in my chassis. What do I do? A: You can use vertical mount resistors or you can use a single high-power resistor. Highpower resistors are available in 25W and compact 50W packages, but these require special mounting techniques. Download App J0414: High Power Resistors to learn more. You can also use TO-220 style resistors with heatsinks, such as those offered by Caddock and sold by our distributors listed on this web site. Q: My voltage rail is above 300V, so I need to use both R1 and R2, but I'm not sure how to connect them in series. What do I do? A: Download App J0417: >300V Power Supply Schematic, which shows a typical configuration. You will need to adjust the R1/R2 values if your voltage rail is other than 300V. See App J0413: R1/R2 Selection Chart. Q: What mounting hardware do I need and where can I buy it? A: Download App J0412: Parts, Suppliers, & Accessories. Applications Q: How do I connect the Music Rail to a negative voltage rail? A: Below 30V, the connections are the same as for a positive rail. Above 30V, you must reverse the two protection diodes. All other connections remain the same. To see a schematic for a negative installation, download App J0410: Negative Power Supply Schematic. Q: How do I connect the Music Rails for a bipolar (+/-) power supply? A: Download App J0321: Bipolar Power Supply. Q: How do I optimize Music Rails for a DAC? A: A special low-voltage technique is required for DAC's. Download App J0308: DAC Applications. Q: How do I optimize Music Rails for tube amps? A: A special high-voltage technique is required for tube amps. Download App J0310: Tube Amp Applications. More . . . Q: I will be using 15A Music Rails. How do I know if I’m using enough heat sink? A: If you are modifying a power amplifier you can use the existing heat sink. If not, you will need to specify & supply one. In either case, you should run some numbers. Recommended web resources are shown on the main Apps & Data page of the Bybee Labs web site. Testing & Troubleshooting Q: My Music Rail is in place. How do I know if it's working properly? A: First check the voltage drops, then compare the input vs. output noise with a sensitive AC meter or spectrum analyzer. You can also use a scope if the sensitivity is great enough to display noise at the sub-microvolt level. To find voltage drops, see Figs. 2 & 6 in the Technical Data information. Q: The noise level has not dropped at the Music Rail output. Where’s the beef? A: Even the Music Rail produces some noise. Sometimes the noise in front of the Music Rail is just as low as the noise floor of the Music Rail. Wow! One of the interesting things about the Music Rail is that it produces "good noise", i.e., the character of the noise that it does produce is very smooth, like the sound of surf in the far distance. The character of a 3terminal regulator, on the other hand, is more spikey & jumpy, which can put an edge on transients that makes them grating to the ear. So even if the PARD measures the same on an AC voltmeter, it can still sound quite different in its effects on music. A spectrum analyzer will show the difference quantitatively, but this does not always correlate psychoacoustically. Q: The noise level has increased at the Music Rail output. What the frack?! A: Under certain capacitive conditions a Music Rail may produce a low-level, nondestructive oscillation. This oscillatory energy adds to the noise floor, which can be seen on a scope. This can occur when low-value capacitors are placed across the Music Rail output. Oscillation may also occur when the input capacitor is too far away from the Music Rail (see schematics for guidelines). Q: My installation cannot avoid using capacitors across the Music Rail output. Is there anything I can do? A: Download App J0409: Bypass Capacitors. Q: I have tried all the remedies provided in the app notes and I still cannot get my Music Rail to operate as advertised. What do I do? A: E-mail [email protected]. More . . . Q: Shazaam! My Music Rail is in place and it passes all tests. How can I convince myself was a wise choice? A: Besides listening with & without a bypass strap, you can run some tests. After checking the noise, run a signal (or music) into your component and increase the level until you can see it on the rail. Be sure not to exceed the limits of your component and to properly load your power amp. If you can’t see any signal on the rail, try increasing the frequency. High frequencies will be stronger because there is less power supply rejection with frequency. When you see the signal clearly—stop. Now try the same test at the same levels with the Music Rail un-bypassed. If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] J0417 MUSIC RAIL™ APP NOTE: >300V Supply 1 Page For additional information, please visit the Bybee web site at www.BybeeLabs.com ADJUSTMENT FORMULAS D1 current = .005 D2 current = none after C1 charges. Music Rail current = .0115A R1 + R2 = (Vin – 24V) / (.005A + .0115A) R1 + R2 watts = (Vin – 24V) X (.005A + .0115A) The above wattage must be derated. See app note J0413. C1, C2 = Voltage rating must exceed input voltage. D1, D2 = Reverse polarity for NEG supplies; otherwise same. If you need additional help, please contact: [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] J0309 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: Benchmark DAC Installation 1 Page Inside a Benchmark DAC 1, each Music Rail should be placed next to its associated regulator. Use a 4-40 x 3/4"L extension (threaded standoff) to elevate each Music Rail. Use 4-40 set screws to fasten the extensions to the existing standoffs that support the Benchmark PC board. These fasteners can be obtained from www.McMaster-Carr.com . Below are the part numbers: 93330A437 92311A110 91770A108 Aluminum Threaded Round Standoff, ¼” OD, ¾” Long, 4-40 Screw Size Stainless Steel Set Screw, 4-40 X ½” Long Stainless Steel Truss Head Phillips Machine Screw, 4-40 X 3/8” Long There are four regulators in the Benchmark DAC 1. The + / - 18V regulators supply the analog output stage. The +5V & +3.3V regulators supply the DAC chip. There are convenient 2-pin jumpers for each regulator. The jumpers are marked as follows: +18V = JP1 -18V = JP5 +5V = JP2 +3.3V = JP6 In each case, the pin nearest the sidewall connects to the Music Rail input (Vin). The output (Vout) of the Music Rail connects to the other jumper pin. Note: the 2A Music Rail drops 0.5V so this insertion loss will have to be compensated in the low-voltage regs (+5V & +3.3V). To recover this voltage, lift the ground pin from each lowvoltage regulator and insert a diode (the ground pin will have zero volts on it, and will be at ground potential, which you can confirm with an ohmmeter). The diode will boost the output of each regulator by 0.6V, making up the insertion loss of the Music Rail. For positive regulators, the diode should be inserted with the banded end toward ground (reverse it for negative regulators). You can use a 1N4001 diode, or any equivalent diode with a forward current rating of 100mA or greater. Each Music Rail should have its two ground pins (the two outermost pins) jumpered. Next, run a wire from either one of these ground pins to the ground plane of the corresponding regulator (that part of the PC board that the regulator ground pin is, or was, soldered to). This completes the installation. After installation and power up, you should read a 0.5V differential from input to output on each Music Rail. The RMS noise at each Music Rail output should read 25uV or less wideband. You should also ensure that each regulator is working properly after the mod (the output voltage of each regulator should remain stable when the AC line is decreased or increased). For further installation and performance details please see the Music Rail Technical Data. App J0308 covers general considerations for installing Music Rails in DAC’s . If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] J0321 MUSIC RAIL™ APP NOTE: Bi-Polar Power Supply Schematic For additional information, please visit the Bybee web site at www.BybeeLabs.com BOM (one channel) 15A POS Music Rail 15A NEG Music Rail Silicon thermal pad 2X C1 1uF, 50V film 2X C2 10uF, 50V film 2X R1 1.1K, 2W 2X D1, D2 24V, 1W zener 4X Mounting hardware *For Other Input Voltages: R1 = (Vin - 24V) / (.005A + .0115A) = (D1 + Music Rail current) R1 watts = (Vin - 24V) X (.005A + .0115A) The above wattage must be derated. See app note J0413. C1, C2 = Same capacitance; voltage rating must exceed input voltage. D1, D2 = No change. If you need additional help, please contact: [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] 1 Page J0308 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: DAC Applications 2 Pages When installing a Music Rail after a low-voltage regulator (as in a DAC or other digital application), you may wish to consider the insertion loss (dropout) of the Music Rail. A typical DAC chip is fed from a +5V regulator and a +3.3V regulator. Note that the 2A Music Rail drops 0.5V. This dropout or insertion loss can be compensated by the following technique: To level-shift a 3-terminal regulator, lift the ground pin and insert a diode in series with it. The diode will boost the output of the regulator by 0.6V, making up the insertion loss of the Music Rail. You can use a 1N4001 diode, or any equivalent diode with a forward current rating of 100mA or greater. For positive regulators the diode should be inserted with the banded end toward ground (reverse it for negative regulators). The level-shifting technique works well down to about 3V, even though our datasheet calls out a 4.5V minimum input voltage for the Music Rail. Here’s why: to produce the rated output current, the input voltage must be 4.5V or higher. At lower currents, however, this rating can be relaxed. In other words, although 3.3V is below the minimum rated input voltage, the Music Rail still functions because the current draw of a DAC is very low. You don't normally need to worry about level-shifting regulators that are >5V, but this will depend on the application. Given these workarounds, there is no reason why you cannot benefit from using Music Rails in several locations within your DAC. Location, Location, Location We have found that with a typical DAC, the most critical location is after the +5V regulator that feeds the analog pins of the DAC chip. The +3.3V digital pin of the DAC is less critical, but still provides benefits. Some of our customers also hear benefits when Music Rails are installed after the + / - 15V regulators that feed the analog output stage (not the outputs of the DAC chip itself, but the op-amps that buffer the DAC chip from the main output). To summarize, the hierarchy of benefits is as follows: 1) +5V analog rail of DAC chip (5 stars) 2) +3.3 digital rail of DAC chip (4 stars) 3) + / - 15V rails of op-amp output stage (3 stars) A full setup for a typical DAC would include the following: 1) 3 x 2A POS Music Rail 2) 1 x 2A NEG Music Rail 3) 2 x silicon rectifier diode In a typical low-voltage application, each Music Rail should have its two ground pins (the two outermost pins) jumpered. Next, run a wire from either of these pins to the ground plane of the 4/20/2011 corresponding regulator (that part of the PC board that the regulator ground pin is, or was, soldered to). Try to position each Music Rail close to its corresponding regulator. Post Installation Performance Check After installation and power up, you should read a 0.5V differential from input to output on each 2A Music Rail. Check the output noise with a scope or sensitive AC meter. The output noise should always be less than the input noise. Under certain conditions a Music Rail may produce a low-level, non-destructive oscillation. This oscillatory energy adds to the noise floor, which can then be seen on a scope. This oscillation can occur when capacitors are placed across the Music Rail output. Oscillation may also occur when the input capacitor is too far away from the Music Rail. Occasionally, the use of a diode on the ground pin of a low-voltage regulator will adversely affect its dropout voltage. This usually happens only with tightly cascaded regulators (e.g., a 5V regulator feeding a 3.3V regulator). It may be necessary in these cases to add level-shifting diodes to both regulators. For this reason, you should ensure that each regulator is working properly after the mod, i.e., the output voltage of each regulator should remain stable when the AC line is decreased or increased with a variac. After confirming the performance of the regulators and Music Rails, listen! Demo Straps For those wishing to demonstrate the benefits of the Music Rail by ear, there is a simple method by which the Music Rail can be bypassed: simply connect a bypass strap from input to output. This strap can be switched, or a pair of quick-connects can be used. Just ensure that the strap, switch, and/or connector are rated for the intended load. See app note J0412 for part numbers & suppliers. Bybee Labs Resources For further installation and performance details please see the Music Rail datasheet, which you can download from www.BybeeLabs.com . You can also request our detailed installation procedure for the Benchmark DAC 1 (app note #J0309). We are currently working on a procedure for the Music Hall 25.3 DAC, which will be available in April 2011. If you need additional help, please contact: [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] DAC APPLICATIONS Page 2 J0409 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: Bypass Capacitors 1 Page The Music Rail performance, like many cutting edge IC’s, is bound by certain external capacitive conditions. This vulnerability also affects three-terminal regulators, many of which are subject to the same conditions. Therefore, to ensure best performance, we recommend the following guidelines. Input Capacitance At least 10uF should be strapped from input to ground. Better to use 33uF or higher and place it close to the module until stability is confirmed. You can use film or electrolytic, but if electrolytic is used, you should use 33uF minimum. If the module is within a few inches of the stock cap bank this part may be omitted. Output Capacitance Ensure that no output cap is present. If this is unavoidable, try to make the cap value less than 0.1uF or greater than 20uF. It is possible to go much higher than this, into the thousands of microfarads, if certain precautions are taken. To avoid having the Music Rails self-protect, ensure that the current rating is respected under all operating conditions. To do this you must consider: 1) The load current at turn on 2) The peak capacitive current at turn on 3) The leakage current of the load capacitors So long as the sum of the above does not exceed the Music Rail current rating, it will operate. Test Procedure Under certain conditions a Music Rail may produce a low-level, non-destructive oscillation. This oscillatory energy adds to the noise floor, which can then be seen on a scope. This oscillation can occur when the above conditions are not met. Oscillation may also occur when the input capacitor is too far away from the Music Rail. If a problem is suspected, first check the voltage drops, then check the input vs. output noise with a scope; or better yet, use a sensitive AC meter or spectrum analyzer. To find voltage drops, see Figs. 2 & 6 in the Technical Data or Figs. 3 & 7 in the Quick-Start Guide. If, after trying all of the above, you still fail to achieve proper operation, please contact: [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] April 20, 2011 J0331 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: Installation & Mounting 2 Pages MUSIC RAIL Installation Notes 1. Vin must supply 11.5mA idle current to the Music Rail circuit (plus an additional 5mA to ZD1 when a high-voltage adaptor is used). 2. J1 is the AC ground that bypasses noise currents and input ripple to ground. 3. J12 is the DC ground that returns idle current to the input source. 4. J1 and J12 may be tied together or run separately to optimize noise floor (experimentally). 5. J2-J6 (Vin) can carry 3A each and should be ganged together to carry higher currents. 6. J7-J11 (Vout) can carry 3A each and should be ganged together to carry higher currents. 7. 15A Music Rails must use appropriate heat sink (Pd=2.1V* load current). 8. Transistor on 15A Music Rails must be isolated from ground with thermal insulator. 9. Output capacitor not recommended (see app note J0409: Bypass Capacitors). 10. After installing each unit, insure that correct voltage drop appears from input to output (0.5V for 2A modules, 2.1V for 15A modules). See data sheet for additional test data. 11. When negative polarity modules are used above 30V, the zener clamps in the hi-voltage adapter must be reversed. All other connections remain the same. 12. As a final test, ensure that the output noise is lower than the input noise (if not, see FAQ). MUSIC RAIL Mounting Notes 1. 2. 3. 4. 5. 6. 7. 8. Try to locate the high-voltage adapter parts within 6” of the associated Music Rail. Try to locate each Music Rail within 12” of the stage it feeds. Power resistors in high-voltage adaptors should be derated 5-7 times and should be at least 10mm distance from noise cap. Leave resistor leads 10-20mm long for increased cooling. The Music Rails can be bypassed for demonstration purposes. Simply jumper the input to the output. Wire guage must be appropriate for load current. For coplanar PC board mounting, a set screw can be used to mount each module to an existing board standoff. The mounting collar in each module is isolated and can be mounted directly to the chassis. The mounting collar accepts #4 screws, but can be drilled out to accept 6-32 screws if required. Mounting screw heads and standoffs should be 0.25 diameter max. Do not exceed mounting pad diameter unless nylon or fiber washers are used for isolation. 15A modules can be mounted to existing heat sinks. Simply drill and tap into the heat sink. Use caution. Taps are hard and brittle. Take care not to over twist the tap. If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] Installation & Mounting Page 2 J0414 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: High Power Resistors 2 Pages For all installations above 300V we normally advise using two power resistors in series. If your available space does not allow this, you can turn to 25W or 50W high-power resistors. Whichever you choose, resistors should be conservatively derated* for several reasons: 1. 2. 3. 4. Heat radiation to adjacent parts is minimized. Power resistors can generate prodigious heat into solder joints. Thermal cycling causes solder joints to alternately heat and cool over time. This cycle can soften the solder joint and make it friable if heat is excessive. PC boards can discolor due to excessive heat. Resistors themselves require derating due to ambient heat. 25W Power Resistors 25W power resistors have flat mounting tabs that are designed to transfer heat more efficiently than a wire lead. These tabs can transfer prodigious heat, and precautions must be taken when mounting on terminal strips. We recommend that you tack solder the tabs onto the terminal strip with minimal solder. Then wrap the tab/terminal combination using 24AWG buswire. Finish up with several layers of solder. This will provide a strong mechanical infrastructure, similar to concrete and steel construction. 4/20/2011 50W Power Resistors 50W power resistors are either very large or very compact. There is no in-between. Most applications will not have room for the very large variety, so we will limit our discussion to the very small variety. We are talking here about chassis-mount resistors with built-in heatsinks. These are by far the most efficient means of dissipating power, provided that the heatsink (or fan) is adequate. Heatsink compound should be used, and fasteners should include lockwashers or kepnuts. We recommend the following websites for advice on thermal design: www.signaltransfer.freeuk.com/termegn.htm www.sound.westhost.com/heatsinks.htm If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] HIGH POWER RESISTORS Page 2 J0410 MUSIC RAIL™ APP NOTE: Negative Power Supply Schematic For additional information, please visit the Bybee web site at www.BybeeLabs.com ADJUSTMENT FORMULAS D1 current = .005A Music Rail current = .0115A R1 + R2 ohms = (Vin – 24V) / (.005A + .0115A) R1 + R2 watts = (Vin – 24V) X (.005A + .0115A) The above wattage should be derated. See app note J0413. C1 = Voltage rating must match or exceed input voltage. D1, D2 = Reverse polarity for NEG supplies; otherwise same. If you need additional help, please contact: [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] 1 Page J0412 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: Parts, Accessories & Suppliers 3 Pages We recommend the following distributors for parts & accessories. USA Michael Percy Audio http://www.percyaudio.com/Catalog.pdf CANADA Parts Connexion http://www.partsconnexion.com/resistors_mills_mra5.html UNITED KINGDOM Audiocom International Ltd http://www.audiocominternational.com ______________________________________________________________________ Power Resistors (R1)* Available from Distributors listed above. For power resistors we recommend Caddock, Vishay, and Mills, available from the distributors listed above. Alternates listed below. For power resistors up to 3W we recommend the following series: http://www.vishay.com/docs/28729/28729.pdf For power resistors up to 5W: http://www.koaspeer.com/products/resistors/leaded-resistors/mos/ For power resistors up to 20W: http://www.ohmite.com/catalog/pdf/200_series.pdf For non-inductive power resistors up to 50W: http://www.percyaudio.com/Catalog.pdf For vertical mounting types: http://www.ohmite.com/catalog/pdf/tww_twm_series.pdf * To select R1 from a table, see app note J0413: R1 Selection Chart. To calculate R1 see Bybee Technical Data _______________________________________________________________________________________ Capacitors (C1) Available from distributors listed above. For noise drain capacitors (C1) we recommend the following: any wideband or low-inductance 1uF film caps rated for the rail voltage. For compact high-voltage applications we recommend Solen "Fast Cap" polypropylenes. These are rated at 250V, 400V, or 630V. Specifications can be found at http://www.solen.ca/pdf/solen/fastcap.pdf Other caps may be used, but to obtain maximum noise drain bandwidth, they should be low-inductance film types. _________________________________________________________________________ Zener Diodes (D1, D2) 24V, 1W zener diodes (D1 & D2) are common and can be found almost anywhere. The generic part number is 1N4749A. __________________________________________________________________________ Terminal Strips Available from distributors listed above. For terminal strips we recommend Grennan, IAG, and Yammamoto. Available from the recommended distributors listed at the top of this sheet. For compact layouts we recommend the 3000 series from HH Smith (now Abbatron). This strip has a top & bottom thru-hole on every contact, which allows component stacking & staggering. The contact count is built into each part number, e.g., 3003, 3004, 3005, etc. The 3006 can be seen at http://www.abbatron.com We recommend the 3008 or 3010 (10-lug) when stringing 20W resistors in series for voltages above 300V (see app note J0417: >300V Supply). All of these strips, and other electronic hardware, are available from: http://www.electronichardware.com For the most compact layouts vertical strips can be used. These have become nearly obsolete, but are currently available from Antique Audio Supply. They carry a 3-lug vertical terminal strip (P-0300V). This can be cut down to 2 or 1 as necessary. Go to: http://tubesandmore.com/ __________________________________________________________________________ Mounting Hardware Fasteners for mounting are typically 4-40 or M3 and are available from McMaster-Carr at: http://www.mcmaster.com __________________________________________________________________________ Fasteners & Standoffs Below are some typical SAE fasteners & standoffs suitable for mounting Music Rails, along with their McMaster part numbers: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 92311A108 92311A110 92311A107 92510A030 92510A420 91251A113 91770A096 91770A113 93330A463 93330A439 93330A437 93330A462 93330A435 91757A101 95584A200 1 Pack Type 18-8 Ss Cup Point Socket Set Screw, 4-40, 3/8" L 1 Pack Type 18-8 Ss Cup Point Socket Set Screw, 4-40, 1/2" L 1 Pack Type 18-8 Ss Cup Point Socket Set Screw, 4-40, 5/16" L 100 Ea Aluminum Unthreaded Round Spacer, 1/4" Od, 5/32"L, #4 100 Ea Aluminum Unthreaded Round Spacer, 1/4" Od, 1/8"L, #4 2 Packs Black-oxide Socket Head Cap Screw, 4-40, 3/4" L 1 Pack 18-8 Ss Truss Head Phillips Machine Screw, 4-40, 1/2" L 1 Pack 18-8 Ss Truss Head Phillips Machine Screw, 4-40, 3/4" L 10 Each Alum Threaded Round Standoff, 1/4" Od, 2" L, 4-40 10 Each Alum Threaded Round Standoff, 1/4" Od, 1" L, 4-40 10 Each Alum Threaded Round Standoff, 1/4" Od, 3/4" L, 4-40 10 Each Alum Threaded Round Standoff, 1/4" Od, 1-1/2" L, 4-40 10 Each Alum Threaded Round Standoff, 1/4" Od, 1/2" L, 4-40 Internal-Tooth Lock Washer #4, .27" OD, packs of 100 External-Tooth Lock Washer #4, 0.26" OD, packs of 100 _________________________________________________________________________ Demo Strap Our recommended bypass strap for before & after demos is made by E-Flite: http://www.e-fliterc.com/Search/Default.aspx?SearchTerm=ec3+connector These 60A twin connectors can be clipped in half, giving two straps, or used in parallel. The part numbers for pre-made 13AWG mating connectors are: EFLAEC304 EFLAEC305 The part numbers for pre-made 16AWG mating connectors are: EFLAEC309 EFLAEC310 _________________________________________________________________________ If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected] App Note J0413: R1 and R2 Selection Chart Vin* DCV 35V 40V 50V 60V 70V 80V 90V 100V 110V 120V 130V 140V 150V 160V 170V 180V 190V 200V 210V 220V 230V 240V 250V 260V 270V 280V 290V 300V 310V 320V 330V 340V 350V 360V 370V 380V 390V 400V 410V 420V 430V 440V 450V 460V 470V 480V 490V 500V 510V 520V 530V 540V 550V R1** OHMS 680 1k 1.6k 2.2k 2.7k 3.3k 3.9k 4.7k 5.1k 5.6k 6.2k 6.8k 7.5k 8.2k 8.5k 9.1k 10k 11k 11k 12k 12.5k 13k 13.5k 15k 15k 16k 16k 8.2k 8.5k 9k 9.1k 10k 10k 10k 10k 10k 11k 11k 11k 12k 12k 12k 13k 13k 13k 13k 13k 13k 15k 15k 15k 15k 16k R1*** WATTS 1W 1W 2W 2W 3W 3W 3W 5W 5W 5W 8W 8W 8W 8W 8W 10W 10W 10W 12W 12W 12W 20W 20W 20W 20W 20W 20W 10W 10W 10W 12W 12W 12W 12W 12W 12W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W RECOMMENDED SOURCES Audiophile quality power resistors are available from: http://www.percyaudio.com/Catalog.pdf http://www.partsconnexion.com/resistors_mills_mra5.html Industrial quality power resistors are listed below: For power resistors up to 3W: http://www.vishay.com/docs/28729/28729.pdf For power resistors up to 5W: http://www.koaspeer.com/products/resistors/leaded-resistors/mos/ http://www.mouser.com/catalog/specsheets/XC-600044.pdf For power resistors up to 20W: http://www.ohmite.com/catalog/pdf/200_series.pdf For vertical mounting types: http://www.ohmite.com/catalog/pdf/tww_twm_series.pdf The above parts are available from: http://www.mouser.com http://www.digikey.com http://www.masterdistributors.com + + + + + + + + + + + + + + + + + + + + + + + + + + R2** OHMS R2*** WATTS 8.2k 8.5k 9k 9.1k 9.1k 10k 10k 10k 11k 11k 11k 12k 12k 12k 13k 13k 13k 13.5k 13.5k 15k 15k 15k 15k 15k 16k 16k 10W 10W 10W 12W 12W 12W 12W 12W 12W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W 20W FOOTNOTES * For in-between voltage values select closest resistor value corresponding to your rail voltage (Vin). ** When R2 is called out it must be placed in series with R1. DERATING NOTES *** Resistors are conservatively derated for several reasons: 1) Heat radiation to adjacent parts is minimized. 2) Power resistors can generate prodigious heat into solder joints. Thermal cycling causes solder joints to alternately heat and cool over time. This cycle can soften the solder joint and make it friable if heat is excessive. 3) PC boards can discolor due to excessive heat. 4) Resistors themselves require derating due to ambient heat. J0310 For additional information, please visit the Bybee web site at www.BybeeLabs.com MUSIC RAIL™ APP NOTE: Tube Amp Applications 1 Page Addresses issues associated with high-voltage apps. For all installations above 30V high-voltage adaptors must be used. We have now recommend a second 24V, 1W protection zener in the Hi-V adaptation (see Fig. 6 of Technical Data). This diode should be placed from the input of the Music Rail to J1. This is in addition to the diode connected from the input to J12.* Whether high-voltage, or any other power supply, the best place to locate the Music Rail is at the tail-end of the supply. The Music Rail is designed to interface directly with the audio circuit. In this configuration, the Music Rail is best placed to filter input noise on one side, and to bypass circuit signals on the other side. The same is true for a switching supply. Just be sure that if you remove filtering components in the raw supply you do not exceed the input ripple limit of the Music Rail (300mV for the 2A Rail and 1.8V for the 15A Rail). This limitation includes any sudden shift in DC status that exceeds the input ripple limit. When this input limit is exceeded, no damage will occur, just intermittent operation, which means that the Music Rail will stop filtering until the peak input subsides. This ripple limit is why we don't normally recommend using the Music Rail to feed output or driver stages in tube amps unless certain precautions are taken. In practice, this problem can be eliminated by using a long time constant ahead of the Music Rail. In other words, if you observe the Music Rail output jumping around on the scope, slow down the input (i.e., add more RC on the input side, or use regulation). For example, at a voltage of 300V in an unregulated supply you might need to use 6.8K combined with 100uF shunt capacitance ahead of the Music Rail. Of course, if a regulator is present, no time constant is needed, since the regulator will provide a steady input voltage well below the ripple limit of the Music Rail. This need for a long time constant in high-voltage applications is why it is usually more convenient to use the Music Rails on the input stages and filament supplies of tube equipment. In filament supplies, there is no need for a long time constant ahead of the Music Rail. Only in hi-V apps is this required. That is because high-voltage transformers step up AC line transients, making them larger. Also note that the 15A Music Rail has more input ripple headroom than the 2A Rail. This can be useful in supplies where long time constants are not possible. You may also find the 15A Rail more useful in low-voltage, unregulated supplies for this same reason. Just bear in mind that the 15A Rail has a 2.1V dropout, so you will need to make this up at the input. * For positive voltage the diode bands face the input of the Music Rail. For negative voltage, the bands must be reversed. If you need additional help, please e-mail [email protected] ## MUSIC RAILS are manufactured in the United States. © 2011 Bybee Labs, Inc. 8390 East Via de Ventura F-110 Scottsdale, Arizona 85258, USA 1-480-998-2880 / [email protected]