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Benchmark Media Systems, Inc. 

 
 

 

DAC1 

Instruction Manual 

 

2-Channel 24-bit 192-kHz 

Audio Digital-to-Analog Converter 

 
 
 
 

 
 
 
 
 

 

 
 
 
 
 
 

 

Summary of Contents for DAC1 HDR

Page 1: ...Benchmark Media Systems Inc DAC1 Instruction Manual 2 Channel 24 bit 192 kHz Audio Digital to Analog Converter...

Page 2: ...iau L DAC1 Manual Rev L Doc 01 31 07 F G Allen Burdick John Siau M DAC1 Manual Rev L Doc 01 10 09 F G Elias Gwinn N DAC1 Manual Rev L Doc 10 26 09 F G Elias Gwinn Manual Revision Notes Revision Note I...

Page 3: ...4 FEATURE SUMMARY 5 FRONT PANEL 6 REAR PANEL 7 CALIBRATION 7 REMOVING TOP COVER 13 JUMPER LOCATIONS 14 JUMPER SETTINGS 15 COMPLIANCE AND SAFETY INFORMATION 18 CERTIFICATE OF CONFORMITY 19 CONTACT INF...

Page 4: ...dio Precision System 2 Cascade test set Measurement limits include detection of artifacts as low as 140 dBFS application of jitter amplitudes as high as 12 75 unit intervals UI and application of jitt...

Page 5: ...switch Preset output levels use multi turn trimmers one 10 turn trimmer per output 20 dB Range 2 dB turn Total jitter immunity with Benchmark phase accurate UltraLock technology Two Error LED s no di...

Page 6: ...out distortion The HPA2 delivers the full rated performance of the DAC1 into two 60 stereo headphones outputs The HPA2 is fully protected against short circuits and overloads VARIABLE GAIN CONTROL The...

Page 7: ...d monitors The factory preset levels may be increased by 5 dB or decreased by 15 dB in order to conform to other studio reference levels This range of levels is also well suited for direct connection...

Page 8: ...outputs are studio grade line level outputs and should not be plugged into microphone inputs without the use of the internal 20 or 30 dB pads or a suitable external pad Unbalanced Analog Outputs The L...

Page 9: ...l We have chosen to use a BNC connector because of its superior reliability The DAC1 comes with a BNC to RCA adapter to allow easy interface with consumer equipment The BNC input has a 75 internal ter...

Page 10: ...Output Level Calibration Controls 10 turn trimmers 1 per output Calibration Adjustability 2 dB turn Output Level Range at 0 dBFS In Calibrated Mode 9 dBu to 29 dBu Attenuator off 1 dBu to 19 dBu Atte...

Page 11: ...itter Induced Sidebands 141 dB 10 kHz 0 dBFS test tone 12 75 UI sinusoidal jitter at 1 kHz Maximum Amplitude of Spurious Tones with 0 dBFS test signal 126 dB Maximum Amplitude of Idle Tones 128 dB Max...

Page 12: ...M Non compatible digital audio format on active input 1 Red AC POWER REQUIREMENTS 50 60 Hz 8 Watts Idle 8 Watts Typical Program 16 Watts Maximum Fuses 2 required 5 x 20 mm 100 V to 130 VAC operation 0...

Page 13: ...omponent failures may affect the long term reliability or may degrade the audio performance Use a static control wrist strap when changing jumper settings Caution Disconnect AC power by unplugging the...

Page 14: ...4 of 39 JUMPER LOCATIONS Position Function N O C X XLR only BNC only Optical only Switchable input Position P5 P8 Attenuation 1 2 3 4 5 6 7 8v 30 dB 20 dB 10 dB 0 dB JP7 75 ohm BNC Termination Left Ri...

Page 15: ...to 1 can be used to disable the front panel source selection switch This feature is useful when the DAC1 is in a critical audio path and only one of the three digital inputs will be used In such an ap...

Page 16: ...ed if the user wishes to loop a single coaxial feed through several other pieces of equipment using a BNC T adapter on the DAC1 A 75 termination must be applied at the last device on the loop and ther...

Page 17: ...ws 0 dB Attenuator disabled Jumper plug between pins 1 and 2 of each header 10 dB Jumper plug between pins 3 and 4 of each header 20 dB Jumper plug between pins 5 and 6 of each header 30 dB Jumper plu...

Page 18: ...e received including interference that may cause undesired operation Safety Information Do NOT service or repair this product unless properly qualified Only a qualified technician should perform repai...

Page 19: ...Benchmark Media Systems Inc Page 19 of 39 CERTIFICATE OF CONFORMITY...

Page 20: ...ystems Inc Page 20 of 39 CONTACT INFORMATION Benchmark Media Systems Inc 203 E Hampton Place Ste 2 Syracuse NY 13206 USA 315 437 6300 Phone 315 437 8119 Fax http www benchmarkmedia com mailto sales be...

Page 21: ...warranty to a period of five 5 years from the date of delivery For the extended warranty to become effective the original purchaser must register the product at the time of purchase either by way of...

Page 22: ...ock when jitter is too high or when the reference sample frequency has drifted UltraLock converters exceed the jitter performance of two stage PLL converters and are free from the slow lock and no loc...

Page 23: ...y remove most of this unwanted noise before it can alias down into lower audio frequencies These crosstalk problems may not become obvious until jitter is present Stop band attenuation can be measured...

Page 24: ...can be done to remove the damage Jitter induced sidebands are extremely complex and cannot be removed with any existing audio device It is therefor important to attack jitter at both ends of the audio...

Page 25: ...operating at a 48 kHz sample rate The top graph shows that the differential phase is better than 0 5 at 20 kHz The bottom graph shows the amplitude response on a highly expanded 0 05 dB division scal...

Page 26: ...e The top graph shows that the differential phase is better than 0 5 at 20 kHz and better than 1 at 43 kHz The bottom graph shows the amplitude response on a highly expanded 0 05 dB division scale Not...

Page 27: ...Analysis of Idle Channel Noise The above graph demonstrates that the DAC1 is free from idle tones and clock crosstalk The highest spurious tone measures 128 dBFS and is AC line related hum The highes...

Page 28: ...hase between 10 audio channels using 5 DAC1 converters operating at 96 kHz The DAC1 converters were chosen from stock at random and measurements were made using a random combination of Coaxial XLR and...

Page 29: ...tion from 20 Hz to 20 kHz is very slight Note that at worst case the distortion is 109 dB less than the 3 dBFS test tone and 112 dB less than the full scale output of the DAC1 This implies that the di...

Page 30: ...Media Systems Inc Page 30 of 39 THD N vs Level at 1 kHz Balanced Outputs Below 4 dBFS distortion is lower than the noise floor of the converter Above 3 dBFS distortion reaches a maximum value of only...

Page 31: ...e Outputs This graph shows the output of the HPA2 headphone amp driving a 60 Ohm load at a very high level 14 dBu Even under these conditions the HPA2 delivers the full rated performance of the DAC1 C...

Page 32: ...a Systems Inc Page 32 of 39 THD N vs Level at 1 kHz Unbalanced Outputs This graph demonstrates the performance of the unbalanced outputs Note that the performance is nearly identical to that of the ba...

Page 33: ...f 39 THD N vs Sample Frequency The above graph shows that the DAC1 provides consistent performance at all sample rates Distortion is not a function of sample rate The minor variations in the above plo...

Page 34: ...op curve is on the right hand side of the graph and is calibrated in UI of jitter The bottom green curve shows the THD N of the DAC1 as the jitter amplitude and frequency is varied at the inputs of th...

Page 35: ...e the sensitivity of the test We set the interface jitter amplitude to its maximum value of 12 75 UI 2075 ns of jitter We then swept the jitter frequency from 2 Hz to 9 kHz and plotted the THD N from...

Page 36: ...dia Systems Inc Page 36 of 39 DAC1 Cable Jitter Immunity The above FFT plots demonstrate that the performance of the DAC1 is not degraded in any way when long cables are used to transmit digital audio...

Page 37: ...37 of 39 XLR Digital Input Sensitivity The above graph shows that the performance of the DAC1 is not a function of the signal level at the XLR digital input When the signal is too low to decode 160 mV...

Page 38: ...f 39 Coaxial Digital Input Sensitivity The above graph shows that the performance of the DAC1 is not a function of the signal level at the coaxial digital input When the signal is too low to decode 12...

Page 39: ...the AES In addition the above plots show that while the AES minimum eye pattern specifications are barely met at the end of 1000 feet of Category 5 UTP cable the DAC1 receivers have enough sensitivity...

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