"AmpliSettembre" 100W Power Amplifier with Regulated Supply for VAS stage and BJT as output devices

Power Amplifier AB class named "AmpliSettembre", classic scheme using BJT as Power Output Devices.
Voltage rails of VAS and Input Stage are regulated in series mode.

"AmpliSettembre" 100W Power Project

Mosfet Amplifier 100W Example Schematic: AB class Principle Diagram

The Following Schematic is an Example about Easy Implementation of Mosfet Power Amplifier.
Power Supply is not regulated.
AB class operating.
100W could be obtained in 8ohm load.
Mosfet 2SK1058 2SJ162.Mosfet Amplifier Example Schematic

Mosfet Amplifier Schematic Example

Dowload PDF schematic document:

Mosfet Amplifier Example Schematic

QUAD 405 Vintage Current Dumping Amplifier 100W My DIY Project

This is my "remake" of first, legendary, Current Dumping Amplifier : QUAD 405.
This is one mix, my personal mix, of  his varius  release, Quad 405 I , Quad 405 II etc.

My DiY Amplifier QUAD 405

I made a stereo version with prototipe in year 2007.
Replacement components:

IC1: TLE2071 OpAmp
TR9-TR10: MJ15003


You can download pdf format below.

Electric Scheme: 

My personal Quad 405 DIY schematic diagram

PCB Layers:

My Quad 405 layout

Quad 405 components placement

Dowload PDF schematic of my project Quad 405 :

Quad 405 schematic EspritAudio

Download PDF PCB plane of my project Quad 405:

Quad 405 PCB Layout PDF

YAMAHA A-1 AMPLIFIER NATURAL SOUND DIRECT DC, FROM 70's WITH LOOK Pt.II

Pt.II

No Fault!!! 

Every component is OK, power BJT are OK!!

So I put new main chord and give power.

Both channel have some volts of offset in their output and the idle current is too low.

So, following the Service Manual I can set the correct value of bias and offset trimmers.

Next step is to change the DISC lamp

VR1-VR2: offset voltage setting trimmer

Yamaha A-1

YAMAHA A-1 NATURAL SOUND AMPLIFIER DIRECT DC , FROM 70's WITH LOOK Pt.I

Not working Amplifier, Yamaha A-1 all Black metal.
I'm almost sure it is broken or it has big trouble because the main cable is cut.

Yamaha A-1

So I start, open the case.....wath I find is...Dust

Dust inside..

I remove dust from jewel...

Yamaha A-1 inside, without dust!!

Inside A-1 demonstrate his particular design, Two Power Transformers and two big capacitors.

Power amplifer circuit is splitted on 2 boards+1 an 2 Big Heat Sinks.

The input and VAS stage is a full of components board, there is also an other little board(+1) only for to mount  the Yamaha double n channel JFET 2SK100

Yamaha 2SK100  Y-K100 JFET

Next Step: let's find trouble!!!