DRIVER KIT OF 006 BOSTRAP 500W

BOSTRAP 500W is a driver amplifier kit NUMBER 006 made by audiophiller of Indonesia. Driver kit designed to drive up to 6 pairs of SANKEN transistor or TOSHIBA transistor.

Some Indonesian homebrewer said if SANKEN transistor means transistor with code 5DY or 2S2922/ 2SA1216 , also if they said TOSHIBA, it mean they are using 2SC5200 paIr with 2SA1943.

But I think some SANKEN transistors were circulated in Indonesia are fake because actually the “last” 5DY production was in 2019. Source: Your 5DY SANKEN could be an FAKE transistor by: RESTOVARIUS

Regardless from the transistor, now we are going back to discuss this schematic diagram.

The designer of this PCB said the kit PCB coud be drove the transistor Power to make up to 500 Watts of audio Power.

When I browse in online shop, I see the name: BOSTRAP 500W. Its interersting me. Here it is of the PCB.

Where to buy the PCB or this Module Kit?

Here are the listing of some online shop to sale 500W PCB:

LINI OLSHOP (PRICE),

GANGSAR 139 (PRICE),

MHL ELEKTRONIK (PRICE),

SERELKOM (PRICE),

ZAHRA AUDIO (PRICE),

And these are link of online shop to sale the Driver Boostrap 500W kit:

GANGSAR 139 (PRICE),

BANGENAN07 (PRICE),

NURJAMAN STORE (PRICE),

WE_MARKETT (PRICE),

AZKA PUTRI MARKET (PRICE)

SIZENA (PRICE),

HERULASU STORE (PRICE),

OUR SHOP16 (PRICE),

PUNGKUT 076 (PRICE),

VERRA STORE (PRICE),

ATIKA 40 (PRICE),

AFIF AUDIO STORE (PRICE),

AINUN CEL (PRICE),

SETIA JAYA SHOP (PRICE),

BEL SHOP (PRICE),

MARKET STORE ID (PRICE),

MIKYONG ID (PRICE),

YON BROTHER 45 (PRICE),

YUDISTORE1 (PRICE),

HANNAH STORE ID (PRICE),

SALMAN SHA (PRICE),

SCHEMATIC DIAGRAM

Its interested to tracing and to be a schematic diagram. After few hour to observe, the result is looks image below:

CLICK THE IMAGE TO ENLARGE

With looking at this schematic, I see that the power amplifier driver circuit is a quite simple and concise circuit.

There are no boostrap capacitors that commonly used in AB- class for positive feedback.

However, the circuit uses the current mirror feature with the present of transistors Q4 and Q7 for Voltage Amplifier Stages.

While Q5 is a voltage amplifier as usual, between the collector of Q5 and the collector of Q7 there is no servo bias transistors present.

This circuit only uses 3 diodes as a rectifier and the voltage drop between the base Q8 and Q9, is always maintained between 1.5 to 2.1 VDC, so that the output of this circuit will be 0VDC.

0 VDC here because the voltage drop across the diodes D3 to D5 is cut off by the 4 VBE voltages each of the 4 driver transistors and the final power transistor.

NOTE:

Some reviewer said that the Driver kit need a supply from 45VDC to 65VDC simetrically.

In the original PCB printed that there is an 100nF capacitor near the input of amplifier. I change it to 100pF.

If you change C2 to 100nF, then this amplifier will be sub-low characterisitic, because the treble frequency is damped by the presence of this input capacitor.

Also in PCB printed that the driver are 2N3055 and MJ2955 but i wrote it be TIP3055 and TIP2955.