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DYNAMIC SOUNDS ASSOCIATES

Phono III

USER MANUAL

120/240 VAC Operation

Naples, Florida

Summary of Contents for Phono III

Page 1: ...DYNAMIC SOUNDS ASSOCIATES Phono III USER MANUAL 120 240 VAC Operation Naples Florida...

Page 2: ...er the power plug indicating 240VAC operation Operating a unit set for 120VAC on 240VAC will cause permanent damage and void the warranty 2 Dynamic Sounds Associates LLC reserves the right to make cha...

Page 3: ...e Phono III are based Within this architecture I was able to achieve the competing goals of high gain and high dynamic range combined with a flat bandwidth of 500 kHz Also since I dislike using coupli...

Page 4: ...ipping box The following items should also be found in the Phono III shipping box Shielded power cord Four Critical Mass Isolators 2mm slotted screwdriver XLR female connector with three wires One pai...

Page 5: ...ections 3 2 and 3 5 o Filter High Pass filter for suppression of excess low frequencies from source material Left Section Push buttons o Input selection A B C o Gain selection referenced to 1kHz 40dB...

Page 6: ...ted EQ group These are not illuminated if RIAA is selected See following section Figure 1A Center upper Section Center Lower Section See Figure 1B This section is a hinged door swings to left that rev...

Page 7: ...ridge will be 120pF o A small opening labelled Reset clears the loading memory for the selected input without using the buttons or remote The LED display will then show either 0 ohm or 120pF Use the p...

Page 8: ...nput connectors and each channel has unbalanced RCA and balanced XLR output connectors It is possible to use both output connectors simultaneously if desired without damage to the unit For example you...

Page 9: ...riate direction Pressing one of the gain buttons will change the gain for the chosen input to the selected value and store it in memory but ONLY if the unit is in the Mute or Standby mode See Section...

Page 10: ...e the input connector selection switch to the Bal position Otherwise it should be in the Unbal position Once the input cables have been connected the cartridge type for each input should be selected u...

Page 11: ...such as the Buss Type GMC fuse If you wish Audiophile grade aftermarket fuses may be used provided they are of the same size and amperage rating 2 2 Installing a Custom Load The internal loading netw...

Page 12: ...of the initial setup procedures that can be performed only when it is operational and start enjoying your DSA Phono III The Phono III should be placed on a sturdy shelf that will provide adequate sup...

Page 13: ...board voltages so the Standby LED will glow but will not blink NOTE If either the Mute or Run button is pressed during the initial 30 sec period after AC power on the Phono III will advance directly...

Page 14: ...Filter Response L R R L This function operates only when in the Mono mode of operation and it differences the left L and right R channels as indicated This function works in conjunction with the phase...

Page 15: ...too low or too high place the unit in either Standby or Mute mode and using the front panel buttons or the remote control select the new gain for that input This will store the new value in the gain m...

Page 16: ...to make corrections This will be the baseline loading value for that input Press either the Up or the Down button on the front panel to store the baseline loading value NOTE The baseline loading data...

Page 17: ...or the proper playback compensation Instead each gain stage of the Phono III has internal feedback to ensure that all forms of distortion are held to very low levels The playback compensation is prov...

Page 18: ...stages has significant advantages for noise reduction which will be discussed in more detail in Section 4 5 The downside of differentially coupling the first and second gain stages is that two matched...

Page 19: ...III design it is capable of providing an output drive voltage of 20 volts peak to peak without any clipping of the audio signal The output stages of the Phono III can provide up to 30mA of drive curre...

Page 20: ...ocated between Stages 1 and 2 and the compensation for frequencies 1kHz is located between Stages 2 and 3 The compensation is designed in this manner to ensure that HF signals from the cartridge which...

Page 21: ...ses of the Phono III for all of the equalization curves shown in Table 2 It will also show how the different curves were incorporated within the Phono III architecture Precision matched components are...

Page 22: ...the voltage regulators and constant current sources for each gain stage the overall noise level at the output is very low First any residual internal noise generated by the voltage regulators or cons...

Page 23: ...for over a year and that additional balancing is generally not required However through long periods of use or use in extreme thermal environments some rebalancing may be required The need for such a...

Page 24: ...e which will assist in locating the adjustment potentiometers on the amplifier boards NOTE Making these adjustments can be facilitated by turning on the filter function button on the right front panel...

Page 25: ...wo sets of output connectors as shown in Figure 10 Moving this switch to the right toward the Pol Bal text will enable the polarization balance to be performed In the normal mode of operation this swi...

Page 26: ...eturn the polarity balance switch to the off position to the left This completes the balancing adjustments that may be required occasionally How often these adjustments may be required will depend on...

Page 27: ...ohms in 10 ohm steps Custom Loading Available on Input A Gain referenced to 1kHz RIAA equalization Selectable 40dB 46dB 50dB 56dB 60dB 66 dB Channel Separation 60 dB Playback Equalization RIAA Accurac...

Page 28: ...nd tampering with or modifications by other than DSA have damaged the product The warrantor assumes no liability for property damage or any other incidental or consequential damage whatsoever which ma...

Page 29: ...y connecting the negative input to ground Unbalanced or in the balanced mode by having the cartridge connected between the two inputs Balanced The balanced configuration increases the voltage gain of...

Page 30: ...no shield it is necessary to determine which wire is and which is If possible remove the shell of the detached RCA connector and see which wire is connected to the center pin this wire is and the othe...

Page 31: ...es as they became known to be used for both recording and playback The playback curve is the inverse of that used during the recording process Different record labels had different EQ curves for their...

Page 32: ...d record stamping processes They were still producing 78 RPM disks but the allure of a longer playing format was causing a revolution in disk technology The part that was slow to change was the equali...

Page 33: ...Old was used by RCA from 1947 195214 after which RCA added the 3180 sec time constant t1 which gave the roll off shelf of 20dB and which became included in the RIAA curve The Columbia EQ curve was use...

Page 34: ...ate LPs by Decca FFRR used their 78 RPM EQ curve which is shown in Figure B 1 Fortunately the universal adoption of the RIAA curve has rendered these label specific EQ curves obsolete and the issue fo...

Page 35: ...s supposed to correct for some cutter head issues however this has largely been proven unnecessary and is not part of the RIAA EQ This option is not included in the Phono II or the Phono III In design...

Page 36: ...designed for the Phono III encompasses both of these two low pass filters but with the appropriate components selected by miniature relays B 3 2 1 EQ above 1 kHz The EQ for frequencies 1 kHz is accomp...

Page 37: ...A EQ Figure B 4 LF EQ Curve Selection Design For the RIAA EQ Sw1 is in the closed position as shown and Sw2 is open as shown The pair of R3 and C0 mounted on the amp PCB and not the EQ module provides...

Page 38: ...o doing circuit board layouts Following assembly of a Phono III the relative18 equalization responses were measured using the CLIOwin7 system In all cases the input signal was adjusted to normalize al...

Page 39: ...DYNAMIC SOUNDS ASSOCIATES Phono III Page 36 of 38 USER MANUAL Figure B 5 G1 Measured EQ Response Compared to Ideal Curves...

Page 40: ...DYNAMIC SOUNDS ASSOCIATES Phono III Page 37 of 38 USER MANUAL Figure B 6 G2 Measured EQ Response Compared to Ideal Curves...

Page 41: ...rsc audio org for further information 2 http pspatialaudio com record_characters htm This provides a very compendious historical review of EQ curves and examines the Decca FFRR curves in great detail...

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