Pass Laboratories XP-25 Manual de usuario

XP-25 Owner’s Manual

passTM

XP-25 Owner’s Manual

Feb. 4, 2010

XP-25 Owner’s Manual

INTRODUCTION:

Pass Laboratories, specifically Nelson Pass and his co-designer

Wayne Colburn have a long history of imagining and successfully

bringing to the discriminating consumer some of the finest phono

stage pre-amplifiers ever offered. Each new incarnation of the

Pass Laboratories phono preamps has pushed their personal limits

as to what level of acoustic bliss is realistically achievable from

“Streaming Analog”©.

Since 1997 the guiding credo for these phono pre-amps remains the

vision that music must flow effortlessly from LP surface to listeners

ear. With each evolution of product that effortless flow should

issue forth with greater detail and clarity while never forgetting or

sacrificing the soul of the music and the artistic intent. The Pass

Laboratories XP-25 does not disappoint.

The XP-25 was brought to market both by copious measurements

and extensive listening through a multitude of tone arm and

cartridge combinations. Listening was given precedent over the

numbers but never at the expense of measured performance. The

result is a dynamic, lush and smooth sound with dramatic detail and

spectacular layering. Those listeners familiar with Pass Laboratories

previous phono pre-amps will be struck by the clear delineation

of bass notes in the XP-25 and the greater sense of music in a real

physical space.

Like some great musicians we get requests! You spoke and we

listened… so that you can listen better. Now the XP-25 a product

designed at the intersections of excellence, adaptability and

convenience.

The twin chassis XP-25 eclipses the already exceptional performance

of the well-reviewed and well-received XP-15: delivering enhanced

RIAA performance at a fraction of the previous distortion. With

the XP-25 you are going to discover a whole new dimension of

dynamics, inner detail and spectral richness on your favorite LP’s.

The XP-25 brings all control and cartridge loading functions to

the front panel and presents them in a clear easy to understand

layout. The XP-25 boasts two separate and selectable inputs, ample

adjustable gain along with generous resistive and capacitive loading

choices.

Those listeners and archivists with the desire or need to sample

music from two tone-arms or turntables will be able to do so

instantly with a single XP-25, thus simplifying their complement

of analog equipment and removing one more variable from their

listening chain.

XP-25 Owner’s Manual

The addition of a user selectable high pass (low cut) filter makes

possible the playing of recordings with excessive subsonic

information.

The addition of a user selectable mute control makes possible the

cuing of records and needle drop in absolute silence.

The XP-25 is an uncommonly fine match with very low output

moving coil cartridges which would normally require a transformer

first stage.

By the early 1980’s it was generally acknowledged that lower output

moving coil cartridges were capable of retrieving significantly more

fine detail from record grooves than higher output moving magnet

cartridges. In many instances this was simply a case of having lower

moving mass to accelerate in the electrical generator mechanism of

the phono-cartridge. Moving coils with 3 or 4 turns of the finest

wire attached to the lightest and stiffest cantilevers were capable of

accurately tracking complex musical passages that a few years prior

would have seemed impossible tasks to engineer and listener alike.

The really astute cartridge makers had clearly taken a page from the

automotive and motorcycle racing cognoscenti, whose engineers who

were doing everything in their power to lower “un-sprung mass”

in an effort to get tires to say in intimate contact with the roughest

terrain at the highest possible speeds. In both worlds the ability to

accurately track the impossible landscape is the ultimate goal…..

minimal moving mass associated with a compliant suspension is a big

part of the answer.

Unfortunately the active electronics that were capable of extracting

signal at those low levels, frequently then buried much of that signal

in their own noise floor. Step-up transformers generally addressed

the noise issues, but frequently lost the very fine detail somewhere

in the transformers iron core. For the time, the promise of the best

moving coil cartridges went un-realized

The XP-25’s high gain and exceptionally low noise figure allow for

ample output and detail from cartridges providing as little as 40 uV

(micro-volts) of signal at the phono input.

The adjustable gain options of the XP-25 make this unit immune

from overload with any high output cartridge of which we are

familiar.

The XP-25 is as much a pleasure to use as it is to listen through,

thank you for trusting your ears and your vinyl collection with us.

XP-25 Owner’s Manual

Before you sit back and listen, take time to read and understand

cartridge loading. When you find the desired setting, please record

that setting so that you can come back to it in the future. For your

convenience we left space at the end of this manual for just these

sorts of details.

TECHNICAL DETAILS:

As previously indicated the XP-25 is a twin chassis design. One

chassis holds the fully filtered and regulated power supplies and

the second chassis houses the analog gain circuits, input switching,

loading and all those details and features normally associated with a

reference RIAA phono stage.

The two chassis are interconnected with a shielded and filtered Din-

25 cable. This Din-25 cable only carries power, never analog signal.

As far as this product is concerned you may use either Din-25 power

connector on the power supply chassis to link-up with the XP-25

control module. Both power connectors are identical and provide

identical performance from the phono-stage. The second Din-25

connector is capable of powering either another XP-25 phono-stage

or a Pass Laboratories XP-20 pre-amplifier without degradation of

measured or perceived performance.

Consumers frequently ask us if they may substitute a Din-25 cable

of their choice for the one Pass Laboratories supplies. The answer is

yes, provided that cable carries all the necessary legal approvals. For

those of you so inclined, please pick a shielded and filtered cable so

as to not degrade the full measure of performance your new XP25 is

capable of producing.

Never attach or detach the Din_25 cable with the power supply,

powered up from the wall. Always unplug your XP-25 from line

voltage prior to attaching or removing the Din 25 cable.

The rear of the power supply chassis has a standard IEC 320 power

inlet module a fuse holder and twin Din-25 power connectors. As

with the Din-25 cable, the user is free to substitute a suitable IEC

power cord of their choice. This product accepts any cordset with

an IEC 60320 C13 connector or equivalent. Be aware however that

the XP-25 power supply is not particularly sensitive to differences in

properly terminated power cords.

If you substitute an aftermarket power cord you need to be aware

of the following. The ground pin on the power cord provides this

XP-25 Owner’s Manual

product’s safety ground, for your safety and the integrity of this

product the safety ground must never be defeated. Additionally this

product has filter components in the AC line that are designed to

shunt unwanted noise from the power-line to ground. Defeating

the safety ground will ultimately defeat some of the performance

advantages built into this product.

To insure maximum performance and maximum safety use only

power cords that are grounded and carry all the necessary approvals

and directives from the local regulating authorities.

Lets talk about AC power requirements. Your new XP-25 is built

voltage specific to your market. Line voltage is determined at the

time of construction and is not changeable. The products voltage

and current requirements will be indicated on a tag affixed to the rear

panel of the XP-25’s power supply chassis. This tag will indicate a

nominal 100 volts, 120 volts, 220 volts, or 240 volts with allowances

for normal variations of the nominal indicated build voltage.

The AC Line Voltage in all instances will be 50 - 60 Hz. Please verify

that that voltage indicated on the product is consistent with the

nominal voltage supplied at your location.

All XP25 products are protected by a voltage specific type 3AG

fuse (1/4” x 1-1/4”). For 100 Volts ac and 120 Volts ac the fuse

will be 1 amp, for 220 Volts ac and 240 Volts ac the fuse will be 

amp. In all instances the fuse will have a slow blow time constant.

Substitution of another time constant other than “slow blow” at

the same amperage will not harm this product, but we would not

expect longevity from the fuse element. It is not suggested that

you substitute any other fuse type or fuse rating, deviation from the

indicated physical size of fuse (1/4” x 1-1/4”) may cause significant

physical damage to the fuse holder and put the product and your

safety at risk.

ADJUSTMENT:

In order to set the XP-25 in a way which optimizes the performance

of your phono-cartridge it will be helpful though not absolutely

necessary that you have some information and set up suggestions

on that specific cartridge. If you do not have data on the cartridge

and do not wish to re-invent the wheel, contact the dealer or the Pass

Laboratories factory. We will attempt to help you with that data, but

by no means do we have data for every cartridge arm combination

ever built.

At the bare minimum you should know and have set the suggested

XP-25 Owner’s Manual

optimal tracking force for the cartridge and have already set the

overhang and vta as per the tonearm makers instructions, anti-skate

and azimuth if possible.

The usual procedure is to select input jacks on phono pre-amps

based on cartridge type, Moving Magnet or Moving Coil. As

previously indicated the XP-25 is not typical and is designed

to simplify your life. With the XP-25 cartridge types will be

accommodated by gain and loading selections from the XP-25 front

panel.

In general MM (moving magnet) cartridges will require a gain setting

of 53 dB, MC (moving coil) a setting of 66dB or 76dB. Moving

Iron cartridges, usually 66dB. However there are no fixed rules, the

requisite setting is that setting which works best in your situation.

Some listeners will select gain based on a sonic preference others

simply will choose a setting that brings their phono system output on

parity with their other source components. Either choice is equally

valid.

Moving magnet and moving iron cartridges typically work very

well with a series loading of 47k-ohms and 100 pf of parallel

capacitance. Like gain, these settings too are selectable from the

front panel of the XP25. Presuming 47k-ohm in the case of moving

magnet, greatest benefit comes from exploring the pallet of available

capacitive loading choices. Infrequently moving magnet cartridges

will perform best at other than 47k-ohm but that would be an

exception.

Moving Coil cartridges frequently do best with lower impedance

loads and see little advantage from additional capacitance. From the

front panel your choices of cartridge loading will be as follows:

Resistive loading choices; 30 ohm, 50 ohm, 100 ohm, 160 ohm, 250

ohm, 320 ohm, 500 ohm, 1k-ohm, 47k-ohm

Reactive loading choices; 100 pf, 200 pf, 320 pf, 430 pf, 530 pf and

750 pf.

If you have other than a moving coil cartridge, please take time to

read the short treatise on moving coil cartridges, the philosophy

and exercise of how one might go about adjusting for a particular

cartridge is not exclusive to the moving coil.

While the loading of moving magnet cartridges is rather straight

forward, the loading of moving coil cartridges is at best a very

inexact science. Specific requirements for loading moving coil

devices should be taken (and offered) very lightly.

XP-25 Owner’s Manual

The XP-25 is not typical and I encourage you to think separately

from the cartridge manufacturer and choose your resistive loadings

accordingly.

As for example with the very lowest output cartridges, the cartridge

maker likely anticipated a transformer being used as the initial

stage of gain, the XP-25 with its active elements is a very different

proposition from a transformer as seen by the cartridge. This

fundamental difference of circuit topology can affect loading

preferences.

As an added complexity; part of the cartridge loading is always

provided by the lead-in wiring. The XP-25 is sufficiently revealing

such that the resistance and reactance of that wire should be

accounted for in choosing loading values in the XP-25. As long as

you derive your final setting empirically through careful listening you

may ignore these wire effects; however your cartridge will not.

An improperly loaded cartridge will suffer every unwanted sonic

anomaly, ranging from lack of definition and bass to a very strident

and screechy high end.

Cartridge loading is a compromise between what works best for

the cartridge and what sounds best for the listener. Specifically in

selecting a cartridge load, we will be listening for a compromise

loading which sounds best across the whole audio spectrum and

specifically not that loading which optimizes one cut on one LP.

The front panel controls of the XP-25 load each channel of the

phono-cartridge independently through closely to preserve the best

possible spatial elements of recordings. The XP-25 is a dual mono

design, which minimizes cross talk between channels. The loading

resistors and capacitors are isolated from the front panel switches to

provide the best possible signal to noise figures possible.

I suggest you start with the following for moving coil cartridges:

Always, ALWAYS reduce the volume or mute the output of your

preamp before making any adjustments of the XP-25 cartridge

loading. Load and input changes made to the XP-25 have a small

but non-zero possibility of sending pulses to your pre-amplifier that

could damage loudspeakers provided the volume of the pre-amplifier

is set sufficiently high. Damage to your equipment is highly unlikely

but in light of the effort and expense your equipment represents we

believe that caution however un-necessary is warranted.

Start by selecting an initial resistive load of 100 ohms. Give the

XP-25 electronics a couple of minutes to settle in and listen to the

XP-25 Owner’s Manual

system critically for some time (10 minutes to 1 hour) using various

musical selections that you are familiar with.

Once again reduce the gain on your preamp and select the next

lowest resistive loading value (50 ohms) from the XP-25 front panel.

Once again give the electronics a couple minutes to settle in and

listen to the same musical selections as before. If your test selections

sound better with the new 50-ohm loading you can be assured

that the loading change was in the correct (lower resistance in this

example) direction.

If this second load selection resulted in an even more pleasant

presentation of your chosen musical selections, select the next lower

resistive value, 30 ohms, and listen to the same selections once again.

At some point you will find a value where the perceived sound

deteriorates, move back to the last value that sounded excellent.

Once this has been done, you have reached the apparent optimal

resistive loading.

If going below 100 ohms resulted in degraded sound, then obviously

the correct change would have been to have gone upward to 160

ohms, where you would repeat the listening test. I am sure you get

the idea, it is not complicated, but it can be time consuming.

Capacitive loading follows the same rigor and affects the finer

points of resistive loading. The final and optimal setting will require

alternating between resistive and reactive loading elements, peaking

each element in turn until no further gains are achieved.

Capacitive loading will not affect moving coil cartridges to the same

extent that capacitive loading affects moving magnet cartridges but

the effect may be worth considering and optimizing this parameter

once resistive loading is optimal.

Again I would like to stress that you are listening for a musical

balance in the selections that you play. Some loading selections will

offer better bass but suffer from poor high-end resolution, some

will have spectacular high-end definition but have a flat sound stage.

You are seeking an optimal condition with correct spectral balance

in conjunction with correct spatial information. The XP-25 equips

you with the tools for the task. Finding the best compromise will

however take time.

Do not make the mistake of setting the XP-25 such that it enhances

one recording only, listen to a variety of well-recorded material and

adjust accordingly. Avoid the folly of only auditioning and adjusting

to your favorite LP.

XP-25 Owner’s Manual

Once you have found the optimal settings, take the time to record

those settings, so that should the need ever arrive, you can replicate

your personal best settings quickly and with minimal effort. Of

course whenever your change cartridges or wiring between the

phono cartridge and XP-25 it would be wise to revisit your selected

settings and make the requisite addition to your notes. Space is

provided at the end of this manual to record those settings.

PRODUCT PHILOSPHY and DESIGN:

For a very long time there has been faith in the technical community

that eventually some objective analysis would reconcile critical

listeners subjective experience with a repeatable laboratory

measurement protocol. Perhaps this will ultimately occur, but in

the meantime audiophiles largely reject bench specifications as an

indicator of audio quality. This is appropriate; the appreciation of

audio is a completely subjective human experience. We should not

more let the numbers define audio quality than we would let chemical

analysis be the ultimate arbiter of fine wines. Measurements are

certainly critical, they can and do provide a measure of insight, but

are no substitute for human judgment of that which is pleasant.

As in art, classic audio components are the results of individual

and collective efforts that reflect a coherent underlying goal and

philosophy by the major participants. If successful, they make both a

subjective and objective statement of quality, which is meant to illicit

appreciation in the final product. It is essential that that the circuitry

of an audio component reflects a philosophy which addresses the

subjective nature of its performance first and foremost.

Lacking the ability to completely characterize performance in an

objective manner, we should take a step back from the resulting

waveform and take into account the process by which it has been

achieved. The history of what has been done to the music is

important and must be considered a part of the result. Everything

that has been done to the signal is embedded in that signal, however

subtly.

Experience correlating what sounds good to knowledge of

component design yields some general guidelines as to what will

sound good and what will not sound good in real life.

1) Simplicity and a minimum number of components is a key

element, and is well reflected in the quality of better tube

designs. The fewer pieces in series with the signal path, the better.

This is often true even if adding just one more gain stage will

XP-25 Owner’s Manual

improve the measured performance.

2) The characteristic of gain devices and their specific use is

important. Individual variations in performance between like

devices is important, as are differences in topological usage.

All signal bearing devices contribute to the degradation, but

there are some different characteristics that are worth

attention. Low order nonlinearities are largely additive in

quality, bringing false warmth and coloration, while abrupt high

order nonlinearities add harshness.

3) Maximum intrinsic linearity is desired. This is the

performance of the gain stages before feedback is applied.

Experience suggests that feedback is a subtractive process; it

removes information from the signal. In many older designs,

poor intrinsic linearity has been corrected out by large

application of feedback, resulting in loss of warmth, space

and detail.

We give these precepts a great deal of thought in the design and

voicing of product so that you do not have to. You only need to

address the cartridge loading till it sounds good to you. Once set you

can relax and focus on the results.

WARRANTY:

Please check with the factory authorized distributor in the country where

you are purchasing this product for specific warranty information.

All Pass Laboratories products purchased new from an authorized Pass

Laboratories dealer in North America are covered by a transferable, limited

3-year warranty. This warranty includes all parts and labor charges incurred

at the factory or factory specified repair facility, exclusive of any subsequent

or consequential damages. Damage due to physical abuse is specifically

excluded under this warranty.

For this warranty to apply the customer is responsible for returning the

product unmodified to the factory within the specified warranty period.

The customer assumes all responsibility for shipping and insurance to

and from the factory or a factory specified repair facility. The conditions

and stipulations of this Pass Laboratories warranty only applies to units

originally sold new through an authorized dealer. Warranty on factory

repair is 60 days and covers only the scope of the original repair.

Non-North America customers should consult with their original Pass Labs

dealer or distributor for warranty repair instruction prior to contacting the

factory or shipping product to the factory for repair.

Tabla de contenidos

Otros manuales de Amplificador de Pass Laboratories

Pass Laboratories

Pass Laboratories Aleph 1 Manual de usuario

Pass Laboratories

Pass Laboratories INT-25 Manual de usuario

Pass Laboratories

Pass Laboratories Xs Preamp Manual de usuario

Pass Laboratories

Pass Laboratories XA200.5 Manual de usuario

Pass Laboratories

Pass Laboratories Aleph 1.2 Manual de usuario

Pass Laboratories

Pass Laboratories XP22 Manual de usuario

Pass Laboratories

Pass Laboratories Pass Aleph 60 Manual de usuario

Pass Laboratories

Pass Laboratories XA25 Manual de usuario

Pass Laboratories

Pass Laboratories X2.2 Manual de usuario

Pass Laboratories

Pass Laboratories Aleph 0 Manual de usuario

Pass Laboratories

Pass Laboratories Pass X250 Manual de usuario

Pass Laboratories

Pass Laboratories Pass X5 Manual de usuario

Pass Laboratories

Pass Laboratories Aleph 2 Manual de usuario

Pass Laboratories

Pass Laboratories XA60.5 Manual de usuario

Pass Laboratories

Pass Laboratories X2.5 Manual de usuario

Pass Laboratories

Pass Laboratories Aleph P Manual de usuario

Pass Laboratories

Pass Laboratories X1000 Manual de usuario

Pass Laboratories

Pass Laboratories XP-10 Manual de usuario

Pass Laboratories

Pass Laboratories XA100.5 Manual de usuario

Pass Laboratories

Pass Laboratories XP-10 Manual de usuario

Pass Laboratories

Pass Laboratories INT-150 Manual de usuario

Pass Laboratories

Pass Laboratories XP-12 Manual de usuario

Pass Laboratories

Pass Laboratories XP-30 Manual de usuario

Pass Laboratories

Pass Laboratories X600.5 Manual de usuario

Manuales populares de Amplificador de otras marcas

ASTRO

ASTRO HVO V40 P Manual de usuario

Marantz

Marantz SUPERSCOPE BLA-545 Instrucciones de montaje

NAD

NAD CI980 Manual de usuario

Technics

Technics SE-CH770 Manual de usuario

Harman Kardon

Harman Kardon HK6300 Manual de usuario

NAD

NAD T975 Manual de usuario

McIntosh

McIntosh MA6850 Manual de usuario

Electro-Harmonix

Electro-Harmonix ENGLISH MUFF’N Manual de usuario

Viatron

Viatron Autrix Manual de usuario

GME

GME GA9800 Manual de usuario

Atlas

Atlas CP700 Manual de usuario

Roland

Roland KC-1000 Manual de usuario

Pyle

Pyle PFMRA350BW Manual de usuario

Advantage

Advantage S-250 Manual de usuario

IRT Electronics

IRT Electronics DVA-3007 Manual de usuario

Dimavery

Dimavery BA-100 Series Manual de usuario

Sony

Sony XM-S400D Manual de usuario

Schertler

Schertler ROY X Manual de usuario