Bryston 10B-SUB, 10B-LR, 10B-STD owner manual Power Amplifiers, Power Amplifier Placement, Cables

POWER AMPLIFIERS:

When power amplifiers of different power capabilities are used, the woofers will likely be driven by the most powerful amplifier and the tweeters by the least powerful amplifier since the woofers can generally be expected to be less efficient. When power amplifiers of equivalent power capabilities are used in a bi-amped system, and when the power amps employ totally separate power supplies for each channel (as all Bryston power amplifiers do) it is desirable to place each power amplifier as close to its speaker as possible and use one channel to drive the woofer and the other to drive the tweeter. Please note that if the power amps being used do not employ totally separate power supplies for each channel, some envelope distortion between channels may occur since the power drawn from the low frequency channel driving the woofer will usually be considerably greater than from the higher frequency channel driving the tweeter.

POWER AMPLIFIER PLACEMENT:

Where there is a considerable distance between the audio signal source and the speakers, it is preferable to reduce the distance between the power amplifiers and the speakers at the expense of increasing the distance between preamp and crossover or crossover and power amplifier. The low im- pedance across the speaker lines is more likely to affect signal quality with distance than is the higher impedance across the preamp to crossover, or crossover to power amplifier cables.

BALANCED versus UNBALANCED CABLING:

If the distance between the power amplifier and crossover or crossover and preamplifier is greater than 30 feet, it may be desirable to use balanced cables to interconnect the two distant pieces of equipment as this may reduce noise pickup. To facilitate this, the 10B crossover is available with bal- anced inputs and outputs (PRO versions) using 3 pin XLR connectors (outputs use male connectors, inputs use female connectors). Pin 3 is the positive (non-inverted or Hot) signal, pin 2 is the negative (inverted or neutral) signal and pin 1 is ground.

Where a long run of balanced cable is used to interconnect the preamplifier to the crossover, and the crossover is placed within a few feet of the power amplifier there is no advantage in using a balanced interconnection between the crossover and power amplifier. Balanced cabling does not reduce noise; it merely reduces the ability of the cable to pickup noise. The balanced output of a 10B Pro crossover can easily be used as an unbalanced output by using XLR pin 3 (positive) as the HOT line and XLR pin 1 as the ground line.

Since there is no phase inversion in the 10B, the negative XLR output pins (#2) can be used in the same way to achieve the same effect and the output will remain un-inverted with respect to the input. In other words, any signal that enters the negative XLR input pin (#2) will exit the negative XLR output pin (#2) un-inverted with respect to the input. Similarly any signal that enters the positive XLR input pin (#3) will exit the positive XLR output pin (#3) un-inverted with respect to the input. It is for this reason that the 10B has not been changed to comply with the AES adopted XLR pin configuration for balanced signals (pin 3 negative, pin 2 positive and pin 1 ground) and retains its original XLR pin- out of pin 3 positive, pin 2 negative and pin 1 as ground.

Note, however, that Bryston’s current production power amplifiers do follow the AES conven- tion. As the above illustrations indicate, however, the 10B PRO models do not introduce any phase inversion and thus can be used with either pin 2 hot or pin 3 hot balanced cable systems without changing the phase relationships of the system.

CABLES:

Bryston supplies a variety of stock audio interface cables and will supply reasonably priced semi- custom cables (including adapter cables and cables with custom printed identification sleeves) upon request. Bryston’s balanced cables employ double insulated, 100% shielded twisted pair cable with