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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 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 difficulty 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 use 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 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 driving 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 create distortion in the
transformer and get less than optimal performance from it.  Generally this is not the case with
transformer coupled loudspeakers, but it does occasionally surface.  In these cases, take
special care that the source does not contain a DC component, and confirm the DC offset of
the amplifier is sufficiently low.  This is easily adjusted by a qualified technician armed with the
service manual.  Again, consult your dealer or call us.

The damping factor of this amplifier is not extremely high as it is with some other high power
products, but it is the same at all audio frequencies and occurs naturally without feedback.
Some people are concerned that they need high numbers for good bass performance, but it
just doesn’t seem to be so.  We suggest that you listen with your ears and not your meter.

The Power Line

Please keep in mind that the data we present on output power for this amplifier is based on a
solid AC power line.  In order to get these high continuous figures, the AC line cannot be
allowed to collapse.  Typically in maximum power testing, a household line will fall from 120
volts to around 105 volts.  This impacts the power that can be delivered on a continuous basis,
and it is probable that you will not get full continuous power at specification.

This should not be the subject of great concern, since in audio usage, these kinds of power will
only occur as brief transients, and under these circumstances the AC line will not load badly,

Содержание X1000

Страница 1: ...Page 1 Pass Laboratories Owner s Manual X1000 X600 X350 ...

Страница 2: ...ect 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 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 ...

Страница 3: ... 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 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 ...

Страница 4: ...ut but the terminal should be 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 are ready to play music The meters read current through the output stage in the...

Страница 5: ...ar 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 adjust 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 fo...

Страница 6: ... 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 create distortion in the transformer and get less than optimal performance from it Generally this is not the case with transformer coupled loudspeakers but it does occasionally surfac...

Страница 7: ... are really bad connections and we recommend that special attention be paid to cleanliness of contact surfaces and tight fit Speaker cables should be firmly tightened down at the speaker output terminals but do not use a wrench They will not withstand 100 foot lbs of torque Hand tightening without excessive force is plenty Source Interaction The amplifier does not care what the source impedance is...

Страница 8: ...output This extra front end supply lowers the distortion and noise of the system and allows the front end to swing the output stage rail to rail with losses on the order of only a volt or so extracting every last possible watt The circuit of the amplifier is completely DC with no capacitors in the signal path There are also no slew rate limiting capacitors in the circuit The high frequency rolloff...

Страница 9: ...except capacitors The answer is I don t have good information beyond that More to the point I would suggest that you not worry about it This is a conservatively built industrial design not a tweaky tube circuit run on the brink If it breaks we will simply get it fixed so sleep well Warranty Information This product is warranted for parts and labor for three years from the date we ship it We do not...

Страница 10: ...back was often overused to cover up design sins elsewhere in the circuit with the result that the amplifier did not sound very good in spite of good distortion measurements Push pull circuits while allowing high efficiency and cheap manufacture did not improve the character of the sound at lower levels where we do most of our listening a deficiency which designers often use feedback to cover up It...

Страница 11: ...sounding amplifiers It was all the rage for a while but is no longer touted with such enthusiasm The solution to TIM is low amounts of feedback coupled with fast amplification high slew rate In retrospect the idea was at least half right but I believe not completely for the following reasons First it presumed that there was really fast signal in music Research conducted independently by Peter Walk...

Страница 12: ...nt on the design The concept is actually very simple Conventional feedback local or not is used to make the output of the circuit look like the input In this circuit feedback was not used to make the input look like the output in the conventional sense Instead it works to make two halves of an already symmetric balanced circuit behave identically with respect to distortion and noise dramatically l...

Страница 13: ...Purists will point out that a balanced version of a single ended circuit will experience cancellation of noise and even order components Just so Interestingly the single ended nature of each half of the balanced circuit doesn t give rise to much in the way of odd order distortion and when the even order components and noise are cancelled there isn t much distortion and noise left In any case Balan...

Страница 14: ...s unique in that at this point the distortion contributed by each half appears out of phase with the signal and we use this to reinforce the desired signal and cancel noise and distortion This occurs mutually between the two halves of the circuit and the result is signal symmetry with respect to both the voltage and current axis and anti symmetry for distortion and noise This means that the distor...

Страница 15: ...ks to precisely match the two halves of the circuit and lets the balanced output ignore the unwanted components As long as the two halves are matched this performance tends to be frequency independent and does not deteriorate over the audio band With mid level distortion figures on the order of 002 this is very high performance for a single balanced gain stage The following pages include a copy of...

Страница 16: ...Page 16 X1000 CURVES ...

Страница 17: ...Page 17 X600 CURVES ...

Страница 18: ...Page 18 X350 CURVES ...

Страница 19: ... plus minus 145 volts Maximum Output Current plus minus 30 amps Input Impedance 22 kohm balanced Damping factor 60 ref 8 ohms nominal Slew rate plus minus 40 V uS Output Noise 500 uV unweighted 20 20 kHz Random noise floor approximately 2 uV Dynamic range 155 dB random noise floor to peak output Balanced CMRR 85 dB 1 kHz input common mode rejection ratio DC offset 100 mv Power Consumption 600 watt...

Страница 20: ...plus minus 105 volts Maximum Output Current plus minus 25 amps Input Impedance 22 kohm balanced Damping factor 60 ref 8 ohms nominal Slew rate plus minus 50 V uS Output Noise 500 uV unweighted 20 20 kHz Random noise floor approximately 2 uV Dynamic range 153 dB random noise floor to peak output Balanced CMRR 85 dB 1 kHz input common mode rejection ratio DC offset 100 mv Power Consumption 600 watts...

Страница 21: ... amps Input Impedance 22 kohm balanced Damping factor 30 ref 8 ohms nominal Slew rate plus minus 50 V uS Output Noise 500 uV unweighted 20 20 kHz Random noise floor approximately 2 uV Dynamic range 150 dB random noise floor to peak output Balanced CMRR 85 dB 1 kHz input common mode rejection ratio DC offset 100 mv Power Consumption 600 watts idle 1800 watts maximum Temperature 20 degrees C above a...

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