Showing posts with label dual. Show all posts
Showing posts with label dual. Show all posts
Sunday, October 5, 2014
DC Power Supply Dual rail Variable Circuit
DC Power Supply Dual-rail Variable Circuit
* The circuit can be placed into the existing Variable DC Power Supply metal cabinet.
* Q1 and Q2 must be mounted on heatsinks. Usually, bolting them to the metal case (through insulating washers etc.) proved effective.
* The full ±15V output can be achieved only if the secondary winding of the supply Transformer used in the Variable DC Power Supply is rated at 48V minimum (center tapped).
* When using this circuit, please set the Current-limit control (P1) of the Variable DC Power Supply to any value comprised in the 50mA - 1A range but not higher.
* The second Op-amp (IC1B) contained in the LM358 chip was not used, but its input pins were tied to the negative supply and the output was left open.
* Q1 and Q2 must be mounted on heatsinks. Usually, bolting them to the metal case (through insulating washers etc.) proved effective.
* The full ±15V output can be achieved only if the secondary winding of the supply Transformer used in the Variable DC Power Supply is rated at 48V minimum (center tapped).
* When using this circuit, please set the Current-limit control (P1) of the Variable DC Power Supply to any value comprised in the 50mA - 1A range but not higher.
* The second Op-amp (IC1B) contained in the LM358 chip was not used, but its input pins were tied to the negative supply and the output was left open.
DC Power Supply Dual-rail Variable Part list:
R1 = 4.7K-1/2W
R1 = 4.7K-1/2W
C1 = 100nF-63V
C2 = 220µF-25V
C3 = 220µF-25V
C4 = 100nF-63V
C5 = 100nF-63V
Q1 = BD437
Q2 = BD438
IC1 = LM358
Tuesday, September 2, 2014
Dual Voice Coil Subwoofers
Dual voice coil subwoofers are becoming a popular choice among car audio enthusiasts who want more flexibility in
Parallel:A dual 4-ohm voice coil subwoofer with its coils wired in parallel presents a 2-ohm load to your amplifier. Since an amplifier produces more wattage at a lower impedance, the parallel connection ensures youll get the most output from your amp. In the same fashion, if you have a stereo amplifier and two DVC subs, wire both subs for 2-ohm impedance (one per channel) for maximum output.The key difference between single and dual voice coil subwoofers is the multiple wiring options DVC subs offer:
- Series: Series wiring lets you configure multiple woofers to one amplifier at an acceptable impedance. Wire both coils in series for an 8-ohm impedance, and then wire two 8-ohm subs together in parallel for 4-ohm total impedance (perfect for most 2-channel amps bridged to mono operation). Another example: if you have a high-powered 2-channel amplifier, wire four 8-ohm subs per channel (each channel sees a 2-ohm load).
- Independent: You can wire each voice coil to a separate channel of your amplifier, if you prefer not to bridge your amp. Independent wiring is a nice option if youre wiring two DVC subs to a 4-channel amplifier — one voice coil per channel. Just make sure the signal going to each coil is exactly the same, or the differences will cause distortion.
DVCs and high-performance amplifiers
Also, if you choose to add an unregulated amp as a power upgrade to your existing DVC subwoofer system, you can simply rewire your subs for optimum impedance. Remember that most car amps are stable down to 2 ohms in normal operation, and to 4 ohms in bridged mode. Its important to check your amps manual for its operating parameters before hooking up a DVC sub thats wired for low impedance.Some amplifiers are designed with an unregulated power supply — these amps are favored by mobile audio competitors for their superior performance. An unregulated amps power increases dramatically when it sees a lower impedance load. For example, an amplifier that produces 75 watts RMS x 2 channels at 4 ohms would double its power to 150 watts x 2 with a 2-ohm load. DVC subwoofers (particularly the dual 2-ohm models) give you the flexibility to wring every bit of power out of this type of amplifier.
A DVC sub offers the same performance whether its wired in series or parallel. Its power handling levels, frequency response, and other specifications do not change — the only difference is the impedance presented to the amplifier. As a result, youll need to use the enclosure thats recommended for your sub, no matter how its wired.
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