Bryston ST Series, 14B ST Manual

Also See for ST Series:

Owner's manual (8 pages)

Dimensional drawing (1 page)

Owner's manual (6 pages)

Table of Contents

Contents

1 Bryston 14B-ST Amplifier Description
2 Installation Setup And Recommendations
3 14B ST Rear Panel Connections
4 SPECIAL INSTRUCTIONS FEATURES AND SPECIFICATIONS
5 SERVICE
6 Documents / Resources
- 6.1 References
- 6.2 Download manual

Bryston ST Series, 14B ST Manual

Bryston 14B-ST Amplifier Description

The Bryston 14B-ST is a Stereo 2-channel power amplifier consisting of two totally independent amplifier modules, each with its own power transformer and +/-60V power supply.

Each audio channel provides connections for balanced or single ended input and will supply a minimum of 500 watts of power into 8 ohms or 800 watts into 4 ohms.

Installation Setup And Recommendations

Your 14B ST is a Stereo Amplifier only and the outputs should never be connected in Series/Bridged or Parallel modes.

Make Sure The Circuit Breaker Switch Is OFF Until All Connections Are Made.

Power Switch(s): There are two power switches on the 14B. The front panel 'ST' Power Switch and the rear panel On/Off Circuit Breaker.

The 14B has two, 2-position slide-switches labeled Power Up and Ext Trig and 1-Circuit Breaker Factory Settings are:

POWER UP – LOCAL,
EXTERNAL TRIGGER – LOCAL,
CIRCUIT BREAKER SWITCH – OFF

After confirming that all switches are in the proper positions and all input and output connections are correctly made, plug the amplifier into the proper wall outlet and activate the circuit breaker switch. The power amplified may now be turn on or off using the front panel 'ST' power switch.

If the rear panel power-up switch is in the 'Local' position and the amplifier is connected to the A/C power source the amplifier will turn on/off using the front panel 'ST' power switch. If for any reason the power is removed from the A/C line (ex: power failure) the amplifier will turn off and will not turn on again after A/C is restored until the front panel 'ST' power switch is manually reactivated.

When the rear panel power-up switch is in the 'Auto' position then any time A/C power is supplied (Power Bar, Switched power outlet etc.) the 14B will automatically power-up without having to activate the 'ST' power switch.

14B ST Rear Panel Connections

Input

The 14B ST has two inputs per channel, one for a balanced source, and one for single ended or unbalanced source. The BAL input connector will accept either a 3 pin 'XLR' type or a 1/4" Tip/Ring/Sleeve type. The positive (+) terminal is pin 2 on the 'XLR' and tip on the TRS. The input impedance is 15K ohms. The input pins are gold plated. Input sensitivity is selectable using the 'INPUT' slide switch. In the 'BAL REG' position 2 Volts in = 100 Watts at 8 ohms output. This is the recommended setting when using Bryston preamplifiers or any pre-amplifier having active balanced outputs. This setting also produces the lowest amplifier noise floor. The 'BAL+6dB' setting adds 6 dB of gain to provide an input sensitivity of 1 Volt in = 100 Watts at 8 ohms output. This setting is primarily for balanced outputs that are transformer coupled, or other low level sources. The 'UNBAL' setting selects the gold plated 'RCA' type tip/sleeve connector. The input impedance is 50K ohms. The output is in phase with the input and the sensitivity is 1 Volt in for 100 Watts into 8 ohms output.

Balanced Vs Unbalanced

Balanced cable interconnects should be used whenever possible, as they provide common mode noise protection from external electrical interference, and with active balanced outputs a 6 dB higher signal level flows in the cable.

The unbalanced cable interconnect is provided for preamplifiers without balanced output. Unbalanced cables should be kept to 10 feet or less. Never use longer cables than necessary, never coil excess cable length, and run signal wires away from and never parallel to A/C power or speaker cables.

Output

Gold plated output binding posts provide different interconnect options. Stripped bare wire up to 3 Ga. can be passed through the hole in the binding post and held in place by tightening the post knob. Additional tightening pressure can be achieved using a coin in the slots of the knob. Wire terminated with banana plugs, spade lugs, or pins are also accommodated by the binding posts. Please observe correct polarity (Red/Black) when making these connections. We recommend gold plated connectors to prevent corrosion and signal distortion. (Bryston has gold plated 5/16 inch spade lugs available). Speaker wire should be kept as short as practical and should never be terminated with connectors that may become confused with A/C power connectors. Speaker cables should be dressed away from input and power cables, and even each other when runs are long.

Remote Power Control

You can turn the power amplifier on/off using a 4 -12 volt A/C or D/C voltage using the 4 position screw terminal connector (see rear panel diagram). Insert the 4 -12 volt wire into the input labeled 'IN' (polarity is not important) and then place the 'Ext Trig' (external trigger) switch into the 'Rem' (remote) position. The power amplifier will now power on and off when the control voltage is applied or removed. The connector positions labeled 'OUT' can be used to power another amplifier in sequence. The 4/12 volt control voltage does not appear at the 'OUT' terminals until after the 14B has completely powered up so this allows sequencing of your power amps without large turn-on surges.

WHEN THE 'EXT TRIG' IS IN THE 'LOCAL' POSITION THE 14B WILL IGNORE THE 4/12 CONTROL VOLTAGE AND WILL POWER-UP ONLY WITH THE MANUALLY ACTIVATED FRONT PANEL 'ST' POWER SWITCH.

Clipping Indicators

The 14B uses tricolor LEDs with green indicating power on, flashing red indicating actual overload or distortion and yellow/orange indicating thermal shutdown. Upon power-up the 14B's LED's will remain "red" until all voltages stabilize and the unit comes out of mute and the LED turns green.

If the LED indicator contains a substantial red content, when program is present, it should be considered as a sign that the level is too high and may cause speaker damage if it continues. It should be remembered that the Bryston ST series are powerful amplifiers, and that it is possible to damage almost any speaker if an amplifier is used in a thoughtless or abusive manner. Bryston will not be responsible for speaker damage caused in this manner.

The clip-sensing circuit uses an AC comparator to detect any source of signal distortion including clipping, short circuits in cabling, excessive DC or supersonic signals, whether at the input or output. Most conditions which could cause the red LED to light for more than a moment or two can be dangerous to your loudspeakers and should be corrected immediately.

If a specific LED remains 'yellow/orange' without signal present, it may indicate a thermal shutdown condition and the channel will remain inoperative until safe operating temperatures return.

Bryston 14B ST Back Panel

SPECIAL INSTRUCTIONS FEATURES AND SPECIFICATIONS

Maximum continuous output power with both channels driven can only be realized on a 120 Volt 20 Amp or 230 Volt 10 Amp version of the 14B ST

Music is a "Dynamic and Transient" condition and the power requirements fluctuate up and down over time with the audio signal. Therefore, under most listening conditions the 15Amp/120 Volt version will be all that is required for the majority of domestic audio/video systems.

If more power is required, then a 14B - 20 Amp version is also available. You must have a minimum of 12 Gauge household electrical wire and a dedicated 20 Amp wall plug in order to utilize this feature. The other option available is to wire for a 240 Volt 10 Amp service and use the 230 Volt 10 Amp European model.

14B-120-Volt 15 Amp Version:

Power rating:	500 Watts into 8 Ω 800 Watts into 4 Ω
Input impedance:
balanced unbalanced	15 k Ω 50 k Ω
Sensitivity:
bal input reg bal input +6 unbal	2 Volt in = 100 Watts / 8 Ω 1 Volt in = 100 Watts / 8 Ω 1 volt in = 100 Watts / 8 Ω
Distortion:	Thd + N.005% 20Hz to 20kHz at 500 watts /8 ohms IMD.005% 60 Hz + 7kHz mixed 4 to 1 Noise – 115db 20Hz to 22kHz bandpass
Current consumption:	Both channels at full power with 8 ohm loads = 19.1A. Both channels at full power with 4 ohm loads = 30.7A. Both channels idle = 1.3 Amps

14B-120-Volt 20 Amp Version:

Power rating:	500 Watts into 8 Ω 800 Watts into 4 Ω
Input impedance:
balanced unbalanced	15 k Ω 50 k Ω
Sensitivity:
bal input reg bal input +6 unbal	2 Volt in = 100 Watts / 8 Ω 1 Volt in = 100 Watts / 8 Ω 1 volt in = 100 Watts / 8 Ω
Distortion:	Thd + N.005% 20Hz to 20kHz at 500 watts /8 ohms IMD.005% 60 Hz + 7kHz mixed 4 to 1 Noise – 115db 20Hz to 22kHz bandpass
Current consumption:	Both channels at full power with 8 ohm loads = 19.1A. Both channels at full power with 4 ohm loads = 30.7A. Both channels idle = 1.3 Amps

14B-230-Volt 10 Amp Version

Power rating:	500 Watts into 8 Ω 800 Watts into 4 Ω
Input impedance:
balanced unbalanced	15 k Ω 50 k Ω
Sensitivity:
bal input reg bal input +6 unbal	2 Volt in = 100 Watts / 8 Ω 1 Volt in = 100 Watts / 8 Ω 1 volt in = 100 Watts / 8 Ω
Distortion:	Thd + N.005% 20Hz to 20kHz at 500 watts /8 ohms IMD.005% 60 Hz + 7kHz mixed 4 to 1 Noise – 115db 20Hz to 22kHz bandpass
Current consumption:	Both channels at full power with 8 ohm loads = 9.5A. Both channels at full power with 4 ohm loads = 15.3A. Both channels idle = 1.3 Amps