Pass X Series Manual电路图.pdf

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1、 Page 1 Pass Laboratories Owners Manual X1000 / X600 / X350 RadioFans.CN 收音机爱 好者资料库 Page 2 Now For Something Completely Different: The X Series are the biggest and most powerful amplifiers we have created, but they are not unique for that reason. We have chosen the biggest and most powerful as the p

2、roper temple for a new concept in high performance audio amplification. Called Supersymmetry, the circuit topology was granted a U.S. patent in 1994, and is the result of 19 years of effort by Pass. The amplifier uses highly matched components in a classically simple balanced Class A circuit. The am

3、plifier contains only two simple stages: the first is a balanced single-ended Class A voltage gain stage. Its output drives a bank of high power Mosfets operated as voltage followers without feedback. These are inherently low distortion types of circuits, but their performance is improved when opera

4、ted in balanced mode through cancellation. Distortion and noise identical to both halves of a balanced circuit will disappear at the output, and in a well-matched symmetric circuit, most of the distortion and noise is identical. Supersymmetry enhances this effect by providing a connection between th

5、e two halves of the balanced circuit that further perfects the match. Any distortion and noise not already identical to the two halves is made identical, and the result is improved cancellation at the output. Unlike feedback techniques where the goal is to correct for the distortion by feeding a gai

6、n stage an inversely distorted signal, Supersymmetry seeks merely to create perfect matching. Matched balanced power circuitry typically sees a distortion and noise reduction of about 90% (20 dB) through a balanced connection without any additional effort. The Supersymmetric circuit delivers another

7、 90% reduction, so that the X series has about 1/100 of the distortion of a conventionally simple amplifier. Actually this ordinary distortion and noise can still be seen at the output of one half of the circuit, but since it is virtually identical on the other half, it goes away at the speaker term

8、inals. This gives good measured performance, which because it is simple, also sounds excellent. Previously these kinds of simple Class A circuits have been popular for their sound quality in low power amplifiers, but have not found application at high power levels due to excessive distortion and low

9、 efficiency. Supersymmetry overcomes this barrier, delivering the sweetness, staging, and detail of very simple circuitry up to kilowatt power levels and beyond. The X Series amplifiers have the tremendous dynamic range (150 dB) to do justice to the 24 bit recordings of the 21st Century. The simple

10、but powerful circuitry moves easily from total silence to explosive transient and back to silence without a trace. Its a spooky experience. Because these amplifiers do not rely on output feedback for high performance, their performance is consistent across the audio band, from DC to beyond audibilit

11、y. They are unconditionally stable into any loudspeaker. If you need even more power, X1000s can be operated in series and parallel arrays. As a practical matter, we offer peak output levels to 64,000 watts. So relax and enjoy your amplifier. Call us if you ever have a problem or question. RadioFans

12、.CN 收音机爱 好者资料库 Page 3 Setup First off, lets be clear about one thing. These amplifiers are very heavy. In the case of an X1000, we strongly suggest that you get four, not two, people to help you lift it. Yeah, maybe two people could do it, but if you get hurt, dont say you werent warned. X600 and X3

13、50 models are not much lighter, either. Make the dealer lift it. You can position the amplifier anywhere you want, but it requires ventilation. We do not recommend placing it in enclosed cabinets or small closets without means for air to circulate freely. The amplifiers all idle at about 600 watts p

14、er chassis, about the same as a hair dryer. Lets talk about power requirements. The amplifier draws about 5 amps (continuous rms) out of the wall during normal audio operation, and this reflects mostly the idle current that we run through the output stage. If you are driving a low impedance load har

15、d, you will draw more than this, but this will not be typical. On this basis, we estimate that you can put two channels on a single 20 amp, 120 volt AC line without problems in most cases. The X1000 is provided with a special standard 20 amp power cord that is not like most of the ones you are used

16、to. It is heavier, and mates to a standard receptacle at the rear of the amplifier. It is probably not compatible with other “after-market” audiophile power cords, so be sure to check before assuming that it will fit. The power cord we provide requires the more modern high current wall sockets, so i

17、t is entirely possible that an electrician will have to come out and install new ones. A diagram of the kind of AC wall outlet required is included here. X600 and X350 models are being provided with the more conventional AC line cord which is rated at 15 amps for your convenience. The chassis of the

18、 X1000 is connected to the earth ground through the power cord. This is the only thing it connects to. It is not attached to the circuit or to the amplifier signal ground. This is essential to operating the amplifiers in series or parallel configurations. The X600 and X350 have their circuit grounds

19、 attached to the chassis in the conventional manner. Under no circumstances should you defeat the ground connection of the power cord. For your safety, the chassis of the amplifier should be earth grounded. We arent kidding. Series or parallel operation of X1000 amplifiers requires an interface adap

20、ter that is essential for such operation. Do not attempt to operate the X1000 in series or parallel without this interface. For more information, contact your dealer or the factory. Looking at the rear panel you will see the AC power cord receptacle, a power breaker switch, two pairs of high current

21、 output connectors, a pair of 5 way connectors for remote turn-on, and one or two XLR balanced input connectors. Make sure that the power breaker switch is off (down). Plug the AC cord into the back of the amplifier, and then into the wall. Then turn the breaker switch on (up). The lights in your ho

22、use will dim for a moment while the power supply charges the capacitors. On the front panel, the single led indicator on the meter should be glowing blue, indicating that the power is on. The meter lights should not be on, and the meter should be parked at the left. If the meter lights are on, and t

23、he meter is up nearly to half-scale, dont get excited, just use RadioFans.CN 收音机爱 好者资料库 Page 4 the front panel stand-by button to go to stand-by mode, with the meter light off and the meter parked to the left. OK, so the amplifier is sitting there in stand-by mode with just the single blue led lit.

24、No speaker connected yet. You can go ahead and connect the source now. The amplifier requires a fully balanced source, that is to say a male XLR connector with pin 1 at ground, pin 2 positive signal, and pin 3 negative signal. Both pins 2 and 3 should be driven by equal levels of signal with opposit

25、e phase. In standby mode, the balanced inputs to the circuit are shorted, and the input impedance of the amplifier will be 2000 ohms, just so you know. Now that the source component is connected, make sure there is no signal coming from it, probably by turning the volume all the way down. The next s

26、tep is the connection of the speaker. If this is the first time out of the box with the amplifier and you are particularly paranoid, you might connect up some cheap disposable speaker first, but I have to say that we have not seen a failure yet, and are not expecting one. On the X1000 and X600 the t

27、wo sets of output connectors on the rear panel are in parallel, for the convenience of those who wish to bi-wire their loudspeakers. The red terminal is connected directly to the other red terminal, and so with both black terminals. On the X350, there is one set per output, but the terminal should b

28、e large enough to accommodate dual spade lugs if desired. With the speakers connected, push the front panel button to activate the amplifier. The meter lights will come on. The meter on the front should go to somewhere between one-third and half way up, reflecting the bias on the output stage. You a

29、re ready to play music. The meters read current through the output stage in the X1000 and X600 and total supply charging current in the X350. At low levels, they should stay pretty constant and if the meters are bouncing around at a moderate or low listening level, it might indicate that you are dri

30、ving a very low impedance load or even a dead short. If your speakers are not known to be very low impedance, say less than 4 ohms, then you should check this out. Do everybody a favor and try not to have shorted output cables. It happens accidentally all the time, and the amplifier is designed to s

31、urvive, but I wouldnt bet the farm on it. With the X350, you will see some meter bounce if the AC line is not constant. This is normal, and simply shows the different charging rate of the power supply capacitors, not the actual current going through the audio circuitry. You will also note on the X35

32、0 that the meter shows the draw of both channels. We had only one meter. Of course its always possible that something could go wrong. If so, dont get excited, just relax. Its really aggravating when something like this doesnt work, we understand, but it will get fixed. At Pass Labs, we go to a lot o

33、f trouble to make products reliable, and the failure rate Page 5 of our amplifiers is almost non-existent. This is small comfort to the few, but take it easy and give us a call if you have problems. Now that the channels are up and running, we can take a moment to note a few things. The meter lights

34、 are blue, subtle lighting in daylight, a little more dramatic at night. The meters themselves read the amount of current going through the amplifier, and that is why they sit near the half-way point, reflecting the bias current we run through them to get low distortion. The bias current seen by the

35、 meters will vary slightly, going down a bit as the amplifiers warm up. Two channels will not always be at exactly the same position. Dont worry about it. If they drift upwards or vary dramatically from each other, give us a call. Later, as you start listening to music at higher levels, you will sta

36、rt to see the meters move up above the bias point. Basically, the amplifier will be operating in pure Class A at current levels that do not cause the meters to move. As the current to the speaker exceeds the bias level, you will see the meter bounce upward from the idle reading. Its pretty simple: I

37、f the meter isnt moving, you are still in pure Class A mode. You will probably be surprised how loud you have to play it before the meter moves. The meter has been calibrated to reflect the 600 watts idle draw of the amplifier, which is about one-third full scale for the X1000 and X600, and one-half

38、 for the X350. The meter is intended as a general indicator of the status of the amplifier and has not been calibrated to reflect any particular values. People are interested in how long it takes for these amplifiers to break in. It takes about an hour for them to warm up, and this is where we adjus

39、t them first. Then we adjust them again and again over a couple of days, keeping the bias and offset in the sweet spot. Our environment is about 23 degrees Centigrade, room temperature, and the heat sinks will rise to about 22 degrees C. above that, for a heat sink temperature of 45 degrees C. In yo

40、ur setup the temperature may vary a bit due to line voltage and ventilation, but it is not a big deal. You should be able to put your hands on the heat sinks without discomfort. The amplifier has a thermal cutout that will disconnect AC power if the temperature exceeds 75 degrees Centigrade. This sh

41、ould never occur in real life. The front end of the amplifier draws about 25 watts even in stand-by mode, so the top cover will always be a little warm. We recommend that you shut the amplifier down using the rear power switch if the amplifier is going to be unused for any extended period. It will n

42、ot hurt the amplifier to be left either in operating or stand-by mode constantly, but it is potentially a waste of energy. Again, it is our experience that a 1 hour warm up is adequate for even the most critical listening experience. Stand-by mode allows a faster approach to optimal conditions as it

43、 keeps the front end circuit fully operational. More things to know: You can remotely operate the stand-by mode by applying 12 volts DC to the single pair of 5 way connectors on the rear of the amplifier. The positive of the 12 volts DC goes to the red connector. This pair of terminals is fully floa

44、ting and isolated, and drives the high impedance coil of a 12 volt relay. This connection has an actual operating range of about Page 6 9 volts to 15 volts. This switching is independent of the front panel button, so if the amplifier is placed in operating mode by the button, the relay will not turn

45、 it off, only on. So much for essential information. Speaker Interface The X Series is optimized for loads nominally rated at 4 ohms and above. You can run the amplifiers into a lower nominal impedance without difficulty, and we are not aware of a speaker on the market that presents unusual difficul

46、ty with these amplifiers. If you wish to maximize power or minimize distortion for loads rated below 4 ohms, we suggest that you parallel 2 or more X1000 channels, which will allow multiples of the 20 amp rating. For example, if you desire to achieve 16,000 watts peak into 1 ohm, you will want to us

47、e 4 amplifiers in parallel. If you want lower distortion at that figure, you will use more. Remember that running arrays of X1000 channels requires an interface unit from Pass Labs. Feel free to consult the factory for the answers to any questions. The X amplifiers do not care particularly about the

48、 reactivity of the load. Reactive loads typically will have slightly less distortion at a given voltage/current level than resistive loads. The X circuit was designed to be quite happy driving electrostatic and other speakers, since it is unconditionally stable and operates without feedback. When dr

49、iving transformer-coupled loads directly, as in some electrostatic and ribbon designs, some attention must be paid to the DC character of the situation. If the transformer primary is being driven raw with no protection from DC and your source has DC voltage, or in cases where the small offset of the power amplifier is still too much, you may