Auna AV2-CD508BT Hi Fi Amplifier to High End Preamplifier AUX bluetooth

How to made an economic High End Preamplifier.

My Auna CD508 project: from Hi Fi power amplifier to High End Preamplifier with Phono MM and MC.
The original amplifier has a switching power supply, the input selector is made by CD4052 and power amplifier is made by Texas Instruments AB class IC, LM1875 in bridge connection. The power rails voltage are +16/0/-16 Vdc and it as some features like tone control, BT connection balance, remote control , motorized volume knob, output relay, 3 inputs(4 with BT) , a tape recording output and a headphones out.
Estimated  power output on 8ohm should be around 50W/CH.

Amplifier Auna AV2-CD508BT before mod

I dismounted the power amplifier section and I made a substitution with my Espritaudio Preamplifier modules: ESPRE

Preamplifier Auna AV2-CD508BT after mod

Bridge connection of LM1875

The ultimate real analog synth for everyone UNO Synth

UNO Synth

IK multimedia combined his two decades of experience in software and hardware development with the expertise of Italian boutique synth-maker Soundmachines and IK’s synth guru, Erik Norlander (one of the brains behind acclaimed synths like the Alesis Andromeda).

Ik Multimedia unosynth

UNO Synth editor

Advanced synth control for Mac/PC and iOS

The UNO Synth Editor is a plug-in and standalone app that lets you access all the parameters of IK’s groundbreaking UNO Synth, the real analog synthesizer for everyone. The Editor lets you go beyond the front panel controls and access deeper programming settings like full 4-stage ADSR envelopes for both filter and amplitude, pulse width and waveform shape modulation of the oscillators, modulation wheel assignments, velocity control and much more. The Editor does not make sound on its own. Rather, it is a controller for the UNO Synth hardware that gives you remote control of this innovative instrument from your computer or mobile device.

UNO Synth editor Mac/PC iPhone/iPad

EL34 Triode Amplifier Single Ended 0 Feedback, 6SL7 e Mos driver & Phono MM input

Description: 
StereoTube power amplifier.
Tube complement: two 6SL7, two EL34.
Configuration: EL34 connected in Single Ended Triode
Output power: 7W
Frequency response: 10Hz–30kHz, ±0.2dB
Input sensitivity: 770mV for rated power. 
Rated load impedance: 4-8 ohms. 
Damping factor: 5 at 1000Hz due to 0 Feedback Design

EL34 SE Amplifier 6SL7

EL34 SE Amplifier 6SL7

Phono Stage  for EL34 SE Amplifier 6SL7

Phono Stage  for  EL34 SE Amplifier 6SL7

Phono Stage  power supply for EL34 SE Amplifier 6SL7

EL34 SE Amplifier 6SL7

Phono Stage  for  EL34 SE Amplifier 6SL7

EL34 SE Amplifier 6SL7 inside

EL34 Push Pull Amplifier triode connection prototype DIY

EL34 amplifier prototype

Description: 

StereoTube power amplifier.

Tube complement: eight 12AX7, four EL34.

Configuration: EL34 connected in Push Pull triode configuration

Output power: 15W

Frequency response: 10Hz–30kHz, ±0.2dB

Input sensitivity: 1000mV for rated power. 

Rated load impedance: 8 ohms. 

Damping factor: 11 at 1000Hz 

EL34 Triode connection Push Pull CFB Paraphrase Inverter Amplifer Schematic from Bartolomeo Aloia Project and Hammond Transformer

This is my first Tube Hi Fi amplifier, I choose to start from a  Bartolomeo Aloia project :
VTAF Volks Tube Amplifier The First by Bartolomeo Aloia
 you can find details on audiodesignguide page.

The project is based around a EL34 triode conection push pull.
The output transformer is a Hammond 1615 witch I would use in Chatode Feddbak connection.

Paraphrase imput stage and phase splitter is a  modified GY50 driver stage board .

Phase Splitter Prototipe Paraphrase inverter

EL34 triode push pull CFB amplifier schematic

Sony TA N902 N900 N901 Esprit Solid State Class A Amplifier Clone II Switching Dual Power Supply

DIY 
My Sony Esprit Clone Power Amplifier!

Power Boards Hetasink

Switching power supply

Sony TA N 902 Esprit Solid State Class A Amplifier Clone

Sony Esprit TA-N902 Power Amplifier:

My design about Sony's clone, power part simulation: 

Making of Audio Projects Testing Dedicated Power Supply

I'm working around board assembly.

Positive rail is ok, negative has to be tested ...I hope it'll be ok!!!

Linear Variable Output Voltage from 3V to 50V, Input voltage Max 60Vdc

Hi Fi power supply +60V 0 -60V DC

A Linear Power Supply designed for Hi Fi appliance capable of +60Vdc,-60Vdc, power diveces cuold be IRFP240 IRFP9240

Next Power Amplifier based on Sony Esprit Series Using No Negative Feedback Architecture

I'm traying to make an amplifier following example of Sony TA-N902 Esprit Sere, the last aftre TA-N900 mono and TA-N901 stereo.
Sony's Esprit  amplifier all haven't Negative Feedback, they had a Voltage Amplifier Stage made by discrete components, which has his proprer feedback and a current stage located out the loop, This architecture decrease the TIM distortion. To minimize THD Sony used his own  patent concerning non-switching power devices, the stage also remain a AB class but  results similar to pure class A.

3D of the  Voltage Amplifiere Stage

Some amplifier are been used as example for schematic or as  components donor.

Power supply is from a PLPS from an old TA-F80,electronic components for VAS are coming from a TA-F500, the chassis is given by a broken Behringer A500.
Other components are new and PCB are made by myself.

Current Amplifier 3D

I used a lot of SMD components, all with 1206 dimension

Soon I'll show the complete work