Pass Labs X1000, X350, X600 owner manual Speaker Interface, The Power Line

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,

Page 6