Wednesday, January 16, 2019

How to DIY Labyrinth Speaker with IWISATO 4-inch HIFI Speaker Empty Cabinet Kits

How to DIY Labyrinth Speaker with IWISATO 4-inch HIFI Speaker Empty Cabinet Kits

It is a pair very popular labyrinth speaker cabinet DIY kits, which adopt double back guide pipe, its return passage measured 1.6 meters, and sound quality is relatively pure. Its panel can be replaced if you have spares. This speaker cabinet kits support 2.5—4 inches full range speaker.

All kits Material: plate is HDF rather than MDF; fasteners are made of industry 8.8 level black hex bolts, lock nuts are made of Brass, fastening nuts of panel is made of steel-plated color zinc. Accessories excluded terminals and wiring. And its cross weight is about 9kg.
 IWISATO 4-inch  HIFI Speaker Empty Cabinet Kits
Exploded view of Labyrinth Speaker with IWISATO 4-inch  HIFI Speaker Empty Cabinet Kits

Front panel and the body of speaker

Inside Structure of Labyrinth Speaker

Exploded view of side plate and front panel, body


Fixed screw and speaker cabinet



There are assembling steps as below and using the last version speaker cabinet as an example.
1. Please check if the shipments are completed, and placed separately firstly.

WHFSC-K2T4(PL)

WHFSC-K2T4(p3l)

2. Use a steel saw blade (or a saw) to cut the inner ribs (waste) from the plywood sheet down, or rip them off, then use a chisel, rasp or sanding wood it that left over burrs.
WHFSC-K2T4(pr11l)

WHFSC-K2T4(pr1l)

3. Install the connecting wire terminal (If there are not holes, please drill hole to fit terminals), prepare to soldering cables are not shorter than 55 cm, and soldering it to the terminal with spare.

WHFSC-K2T4(A18L)

4. Start assembling them with. Black hex bolts, lock nuts
WHFSC-K2T4(A4l)
5. After assembled, polish and smooth the external surface.

6. Install the panel, and soldering the cables to speaker units.
WHFSC-K2T4(A21)

The high-density surface is smooth, seamless laminated without glue, glue also has a thickness of multi-layer stack will increase a few millimeters that lead to the panel will become small, screw holes will not be reached.

At the same time, please avoid moisture.

Mode details, please visit https://www.iwistao.com/collections/empty-woodem-cabinets/products/iwistao-hifi-speaker-empty-cabinet-kits-labyrinth-structure-with-high-density-fibreboard-for-2-5-4-inches-full-range-speaker-unit?variant=18118295257203

Or you may select from the collection below.


Friday, January 4, 2019

How to measure and calculate output power of power amplifier


How to measure and calculate output power of power amplifier

There are three output powers commonly used, rated output power, maximum output power and music power. Here is tube amplifier as an example.

1.    Rated output power (RMS): When power amplifier frequency characteristic and harmonic distortion coefficient can reach the specified technical specifications (generally tube power amplifier distortion should be less than 1%), power amplifier can work continuously for a long time safe continuous sinusoidal signal power.
2.    Maximum output power (PM): it can meet the basic parameters that Maximum output power of the power amplifier at the rated load resistance.
3.    Music Power (MPO): the instantaneous power value that power amplifier can output when Input a large dynamic music signal and keeping that there is not voltage drop of amplifier power supply. This MPO power is typically 4 or 6 times RMS power.

The output power of tube power amplifier is measured by output a 1 kHz sine wave signal from audio signal generator to input to power amplifier to be measured through the attenuator, and send to input end of the measured channel is placed at the maximum position, and other channels are placed at the minimum position, and its tone control is placed at normal position as shown. Then connect a distortion measuring instrument to output terminal of rated load, increase input signal voltage, make the harmonic distortion coefficient of output voltage reach the corresponding specified value, and finally measure the output power under normal operation and continuous signal.


How to measure and calculate output power of power amplifier



Output power measurement method block diagram

The output power is calculated as: P=U2/RL.

If the power amplifier is placed under an 8 ohm load and its output signal voltage is 20v and the distortion factor is 1%, so its rated output power (RMS) of the amplifier is
P= U2/ RL =202/8=50W

In addition, in order to simplify the method of output power of tube power amplifier measurement, we can use the method shown in the figure below to make measurements. The specific method is, placing the measured work in a normal working state, the volume potentiometer is placed at the maximum position, and the music signal output form CD player or the record player or the signal of 1 kHz signal generator self-made is input to the input end of the measured power amplifier, is connected to an 8 ohm speaker or an 8 ohm load resistor at output end of tube power amplifier, and the dynamic voltage across the load is measured by an AC voltmeter or a multimeter AC 20V gear. The average of measured value is its output voltage.



If a tube power amplifier is placed at both ends of the speaker load and the output AC voltage is measured as 10v, the estimated power of its power amplifier is
P= U2/ RL = 102/8=12w