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H.C. Andersensvej 56
8230 Aabyhoej

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    Technical Information

    Here are the Need 2 Know hook-up information for ZapPulse 2.3 and ZapPulse 2.3SE. Before you commence any of the changes shown, turn OFF the power and discharge your capacitor bank!

    1..Power Supply Connection.

    The Power Supply connection is easy and straightforward, and much like any other power amplifier. A specialty is the necessity to keep the supply wires short. The supply wires between the module and the (nearest) supply capacitor (here marked with a blue dart) should be kept at no longer than 10 cm. (4 inches). Preferably shorter! The gauge is not of highest importance - mainly because of the short run - we normally use a 2.5 square mm. (= 12 AWG) solid core copper.

    2..Loudspeaker connection.

    The speaker cable is critical, with respect to sound quality. Normally we use TEFLAR 2, a 14 AWG Silver / Teflon wire. Others can be used as well. Make the speaker cables run short as convenient, while keeping them at distance to the signal wires. (To avoid oscillations). The speaker terminals must be kept insulated from chassis as double connections can cause ground loops.

    3..Connection of a Line input signal.

    Keep these wires as short as convenient, and away from speaker wires and mains wires.

    4..Connection of balanced input signal.

    Keep these wires as short as convenient, and away from speaker wires and mains wires.

    5..Connection of Volume Potentiometer. [option]

    If a potentiometer is added, you can connect your amplifier directly to a CD player or sound card without the need for a preamplifier. We have used a 10k potentiometer here, 22k or 47k are also usable, but more critical with noises and hum.

    6..Remote Standby function. [option]

    ZapPulse 2.3 and 2.3SE modules can be remotely shut down. This is done by connecting the terminal to (signal) gnd. This can be done with a switch as shown, when the switch is on (shorted) the amplifier is in stand by mode. You can parallel as many modules as you like to the same switch. In power down mode the power consumption is as low as 2 Watts per module, and sound is blocked. The module is complete shut down, except power to the input stage, to allow immediate best-performance after powering back on. You can also use a relay, transistor or optocoupler to activate the remote shut down. In this case, connect C of a (NPN) transistor to the terminal, E to the (signal) GND and base to your control signal.

    7..Remote synchronization [option]

    You may want to connect a common sync. generator to keep all modules in your amplifier running the same frequency. Especially if you have 5 - 7 ZapPulse modules in the same enclosure, sync. will relieve you of any noise problems. This is how to connect external Sync. You can connect as many modules as you like to the same sync. generator. Each module loads the sync generator with some 10k. The further you get away from the module's free running frequency, (460 kHz) the higher amplitude is required to sync. it. At 460 kHz a few hundred mV pp will sync the module, while at 1 MHz up to 10 V pp is required to sync properly. DC components in the sync signal of up to 24 V is allowed. So you may use a signal the i.e. goes from 0 - 5 VDC directly. Do NOT use sync signals below 350 kHz, as the coil will start consuming excessive blind currents. The Sync generator should be grounded to INPUT GND of the module, NOT power GND. The input supply should be properly HF decoupled from the main supply, i.e. by use of an RC filter of no more than 1 kHz Fc. When using a sync. generator it is of great importance that it is a type that is insensitive to airborne HF noise. As compact as possible, and built preferably on 4-layer PCB, that absorbs incoming HF noise. Alternatively you can place your generator in its own small grounded faraday's cage. We can offer you a small sync kit that works nicely, built on a 4 layer board. This sync module already has all the power regulation and filtering to directly connect to ZapPulse’s main power supply. Remember to connect both input - and Power GND L and R together as shown to minimize switch glitches.

    IMPORTANT NOTICE We have discovered a side effect of synchronizing the ZapPulse modules, we describe as Mode Jumping. This shows itself only on some loudspeakers, and not on others. At high output powers, a small piano noise is audible, often only in some of the channels. We have found the cause and the solution that can be implemented on next generation Sync. modules. Therefore, anybody who have purchased the sync. module will get a new upgraded module free of charge when they are ready in mid October 2004.

    8..Disable the short circuit protection. [option]

    Add solder to the bubble as shown. After that the short circuit protection is disabled. Do NOT short the outputs while the protection is disabled!! If you later want to activate the protection, simply remove the solder from the bubble again. Best done with braid.

    9..Bridging 2 modules. [option]

    This way you can produce up to 1000 Watts in 8 Ohms / 2000 Watts in 4 Ohms. It is simple to bridge two modules, as you can exploit the plus and minus inputs of a ZapPulse module. Remember to connect the two power GND planes with a SHORT and HEAVY gauge wire. The entire speaker power goes through this GND wire. The load impedance - as seen from the module - is halved, so you may want to disable the short circuit protection (shown above).

    10..External Gate Drive Supply. [option]

    Each ZapPulse module is equipped with an on-board Gate Drive regulator, deriving its power from the main supplies. Unfortunately the regulator accounts for about half the power dissipation from the module. You may want to reduce this power loss, by feeding an external Gate Drive supply of some 20 V DC. Important! This 20 V supply is NOT in relation to Power GND but to the MINUS 60 V rail! So measured from GND it is around -40 V. You can save 4-5 watts of power consumption / heat dissipation per module. Our Predator Power Supply modules have this feature on board, and ready for use if you add a small 15 V AC transformer (also included as a separate winding on some of our dedicated transformers). Important Before you connect the external Gate Drive, de-activate the on-board regulator. This is done by removing solder from the bubble as shown below. Best done using solder braid.

    Convert a 2.3SE to 'low noise' version

    Note this will also lead to lower input impedance, make sure your preamp can drive an impedance of 2k. Most can!

    Click to enlarge!

    Change the resistor in the yellow ring to 100k, and the ones in blue circles to 2k20. You can acquire the necessary resistors from L C Audio.
    After this small change your amplifier runs in low noise mode, where the output noise is reduced by a factor of 10 (20 dB). Input impedance is also reduced from 17k to 2k.

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