New Customer?
Create your accountNo products
Prices are tax included
By buying this product you get 11 loyalty points
Find here a selection of useful and/or essential accessories for this product. These are specially selected by the Audiophonics team according to the characteristics of the product.
Refurbished product - Grade S
Brand new product.
Class A Bipolar MJ15024G / MJ15025G 2x15W 8Ω (Pair)
This double mono amplifier module offers a very classic design, using proven schematics that marked the glorious 1970s of HiFi.
The streamlined schematic offers possibilities of modifications and improvements for experienced amateurs who are familiar with this type of pure Class A schematic. Each module is based on a pair of MJ15025G transistors and a MJ15024G transistor, in order to develop a power of 2x15W under 8Ω and a musical restitution, characterized by a melodic, warm and structured sound.
Mounted on an Aluminum bracket, these modules can be easily mounted on a heat sink (sold separately), in order to efficiently evacuate the heat released by the transistors.
These modules will need to be combined with high quality power supply components for efficient and long-lasting operation. They are therefore aimed at people with a good knowledge of electronic circuitry for measuring quiescent voltages, for example. A minimum 160V transformer with a secondary voltage of 12 to 18V AC will be required.
This amplifier is delivered without filter capacitors (maximum diameter of 30mm).
If you wish to use this amplifier on compression chambers, it will be necessary to provide an anti-pop delay for your loudspeakers.
These modules require two settings for proper operation.
Step 1: Mounting the filter capacitors
Install the filter capacitors first, according to your choice and your needs.
Step 2: Voltage adjustment at VDD/2
Measure the voltage at the external terminals of the diode bridge. Then use the "Offset" potentiometer to obtain half of the voltage measured on the diode bridge. The measurement is made between the GND terminal and the + of the 4700µF capacitor.
Step 3: Setting the quiescent current
Remove the soldering point under the board, indicated by the words "Test J". Place an ammeter between the two "Test J" points. Adjust the potentiometer marked "Quiescent current" to 1.2A. You can then put the soldering point between the two "Test J" points again.
Note: For a precise setting, you can successively repeat these two settings, as they interfere with each other. These settings must be made at the Class A operating temperature.
Specifications | |
---|---|
Product type | Amplifier boards |
Amplifier type | Class A 2 mono board |
Power | 2x15W @ 8Ω |
Transistors (par module) | 2x MJ15025G 1x MJ15024G |
Quiescent current setting | 1.2A recommended |
General | |
---|---|
Recommended supply voltage | 2x 12-28V AC |
Dimensions | 178 x 71 x 44mm |
PCB mounting holes spacing | 100mm |
Center distances of aluminum angle | 50mm |
Weight (per module) | 220g |