Sunday, September 27, 2009

10WATT TUBE HI-FI AMPLIFIER WITH PREAMPLIFIER (6N1P - 6N2P 807 OR EL34)


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100 W 8 ohms MOSFET amplifier with IRF9540 - IRF540

The Schematic Diagram is a basic MOSFET amplifier. Output power is 100 Wrms under 8 ohms or 160 Wrms under 4 ohms with distortion is 0.001 %. Bandwidth at -3 db is from 4 Hz to 100 Khz .
Input sensitivity is 1.2 volts. The gain of 27DB is archived by R7/R6. It may be modified by changing R7 value. Transistors T5 and T6 makes the second differential stage. Transistors T3 and T4 works as a current mirror source. They push the second differential stage to drain equal current. Doing so we get a high gain and an excellent linearity. Output MOSFET transistors works in AB class, their quiescent current is set at 100 mA trough P1. For setting quiescient current, you must set P1 in minimal resistance, place a multimeter in mV DC range on R14 or R15 leads, turn slowly the screw until you read a 33 mV value, which correspond to a 100 mA quiescent current.
F1 and F2 works as an elementary output short-circuit protection. The power supply must have a value between 45 and 55 Volts DC (positive and negative). One heatsink with a thermal resistance less of 2° C / W is required.
All resistors are 1% metal film 1/4 watt. Before connecting a speaker to the amplifier output, connect a multimeter to the output and look on DC output voltage. This level must not be greater than 50 mV. If it is so, check all amplifier for error. Also, change T2 with another device and check again. This amplifier is very simple to build and low cost.

Part List
C1 = 2,2 µF-100 V
C2 = 330 pF-100 V
C3 = 100 nF -100 V
C4 = 100 µF 63 V
C5, C6 = 18 pF
C7 = 100 nF
R1, R3 = 47 K
R2 = 2K2
R4, R5 = 3K9
R6 = 1 K
R7 = 27 K
R8, R9, R11 = 100 ohms
R10 = 10 K
R12, R13 = 470 ohms
R14, R15 = 0.33 ohms 5 watts
R16 = 10 ohms 3 watts
T1, T2 = 2N5401, ZTX558, BC556B
T3, T4 = BF470, MJE350, 2SB649
T5, T6 = BF469, MJE340, 2SD669
T7 = IRF540, IRFP240, 2SK1530, 2SJ162, BUZ900DP, BUZ901DP
T8 = IRF9540, IRFP9240, 2SJ201, 2SK1058, BUZ905DP,
P1 = 2K5 trimmer
F1, F2 = 3 A

power supply
One 2x40 volts 225 VA transformer is exactly what we need for one mono amplifier. For a stereo amplifier, one 2x40 volts 500 VA transformer is required.
Use at least 4x6800 µF 63-80 V reservoir capacitors. The more caps you use, the better the  ripple rejection.
4K7 5W resistors are used to discharge reservoir capacitors once mains is set off.






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Thursday, September 24, 2009

VU Meter with UAA180





The circuit was designed based on the operation of Siemens UAA180 as it functions as a LED driver for light band displays for measuring the level of audio signals.

Part List

R1----22K--1/4W
R2----27K--1/4W
R3----33K--1/4W
C1----1nF
D13---1N4148
P1-----10K--TRIMMER
IC1----UAA180
D1...12-LEDS
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Thursday, September 17, 2009

Stereo Digital Volume Control with DS1802

The DS1802 is a dual audio taper-potentiometer having logarithmic resistive characteristics over the device range. Each potentiometer provides 65 wiper positions with a 1 dB increment per step and device mute. The DS1802 has two methods of device control, which include contact closure (pushbutton) inputs and a 3-wire serial interface for wiper positioning. The pushbutton control inputs provide a simple interface for device control without the need for a CPU. While the 3-wire serial interface, using a CPU, provides the user the ability of reading or writing exact wiper positions of the two potentiometers. The DS1802 can also be configured to operate in either independent or “stereo” modes when using pushbutton control. Independent mode of operation allows for independent wiper control, and stereo mode of operation provides single input control over both potentiometer wiper positions. The DS1802 is offered in commercial temperature versions. Packages for the part include a 20-pin DIP, 20-pin SOIC, and 20-pin TSSOP.

PIN DESCRIPTION
L0, L1 - Low End of Resistor
H0, H1 - High End of Resistor
W1,W2 - Wiper End of Resistor
VCC - 3V/5V Power Supply Input
RST - Serial Port Reset Input
D - Serial Port Data Input
CLK - Serial Port Clock Input
MODE - Mode Select Input
UC0, UC1 - Up Control Pushbutton Inputs
DC0, DC1 - Down Control Pushbutton
Inputs
VU, VD - Volume-Up/Volume-Down
Inputs
B0, B1 - Balance Pot-0, Pot-1 Inputs
GND - Digital Ground
MUTE - Mute
AGND - Analog Ground
ZCEN - Zero-Crossing Detect Input
COUT - Cascade Output


FEATURES
  •  Ultra-low power consumption
  •  Operates from 3V or 5V supplies
  •  Two digitally controlled, 65-position potentiometers including mute
  •  Logarithmic resistive characteristics (1 dB per step)
  •  Zero-crossing detection eliminates noise caused by wiper movement
  •  Digital or mechanical pushbutton wiper control
  •  Serial port provides means for setting and reading both potentiometers wipers
  •  20-pin SOIC and 20-pin TSSOP for surface mount applications
  •  Operating Temperature Range: -40°C to +85°C
  •  Software and hardware mute
  •  Resistance Available: 45 kW
See More DS1802
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Monday, September 7, 2009

Thursday, September 3, 2009

LM-3875 Amplifier with ECC88 Tube Buffer



TECHNICAL SPECIFICATIONS

Power Supply
- toroidal transformer 230V/8*12V/180VA
- output amplifier rails 2*32V DC(2*24V), two bridges with two BYW95C diodes in parallel
- caps Samsung 470uF/100V, four per channel
- tube buffer rails 2*45V (half-wave voltage doubler of 1*36Vac), two BYW95C's, CLC network, 470uF Samsung +100mH+6800uF Panasonic
- tube heating 6V DC, 4xBYW26c, 2* 1000uF Nichicon, stabilized with 7806, 1*1000uF Nichicon .

Input
-standard gold plated cinches, Alps selector 2*1in3, Preh pot 2*10klog .

Tube Buffer
- tube E88CC (NOS Tesla CH), or ECC88 (OS Siemens)
- standard metal-film resistors .

Output Amplifier
- LM 3875 - inverted setup - gain ca 30dB
- input capacitor 2u2/250V ROE MKT, LPF 2*680pF ROE MKC, 2*47nF/160V ROE MKP
- standard metal-film resistors
- output DC offset about -5mV .

Power on Delay
- relay 10A/30VDC on output .

Input Impedance
10k .

Frequency Range
10Hz-20kHz (-1dB, -2dB)/1W/8ohm/THD=0,1%/IMD2=0.075% .

Output Power
36Vpp - 20W RMS (8ohm/both amps on/THD lower than 0.15% 100Hz-20kHz)
24Vpp - 18W RMS (4ohm/both amps on/THD lower than 0.25% 100Hz-20kHz) .

MORE...... http://www.moxtone.com/Tube-buffered%20Gainclone.htm
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