Showing posts with label Power Amplifier. Show all posts
Showing posts with label Power Amplifier. Show all posts

Electronics Constant Current Amplifier

Circuit Constant Current amplifier schematics Circuit Electronics, A few days ago my friend came to the house, he shows the constant current amplifier schematics he found in ~ tima / products / ccamp / ccamp.html. We discuss and discuss until a few days. My friend kept us curious and eager to assemble.
Schematic Constant Current amplifier Original
Schematic Constant Current amplifier Modified

Modified schematic

I've assembled Constant Current Amplifier, but I do not really remember very well, probably from DIY Nelson Pass Zen. Constant Current Amplifier quite different from the single-ended Zen or its variants.

After reading and studying the sources of ~ tima / products / ccamp / ccamp.html and Hen experiment we finally managed to modify it by adding a few components.

In blind tests, the addition of these components produce a sound more amazing.

RX1 and CX1 form the LF filter. RX1 = 100 ohms and RCX1 = 1 nF. = 11 ohm RX2, RX3 = 0.22 ohm 5 Watt and CX2 = 100 nF


I have a custom of using 2 Watt carbon resistor brands Phillips and my legs coated with tin WBT. I have done this long ago. I think the use of carbon 2 watt resistor produces a clear sound, more open and get a natural sound.

Therefore, I use a 2 watt resistor all unless otherwise specified.

For power supply I recommend to use A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers Rod Elliott - ESP. I use a voltage source 21 Volts and 90 Volts.

Assemble survived.
(Hopefully in the next article I will discuss it in more detail)

Schematics for Constant Current amplifier Circuit Electronics
read more "Electronics Constant Current Amplifier"

Electronics 20W Surround audio amplifier with SI-1020G

Circuit 20W Surround audio amplifier with SI-1020G schematics Circuit Electronics,
IC <a href='' title='amplifier circuits'>amplifier</a> surroundHave you been use the IC above? if those who have not, IC above is used or applied to the audio power amplifier. IC processing is quite good for use on amplifier home, or room. IC used is SI1020G who have not very high output with only 20W 8 ohm impedance speakers. Supply voltage ranging from 12 volt to 23 volts.

Below schematic audio amplifier with IC SI1020G
surround audio  amplifier
Part List
R1 = 100K
R2 = 1R
C1 = 2u2F
C2 = 100uF
C3 = 47uF
C4 = 10uF
C5 = 2200uF
C6 = 47uF
C7 = 100uF 

Schematics for 20W Surround audio amplifier with SI-1020G Circuit Electronics
read more "Electronics 20W Surround audio amplifier with SI-1020G"

Electronics Mini and simple power amplifier

Circuit Mini and simple power amplifier schematics Circuit Electronics,
low power amplifier

What is the meaning of the picture above? The above picture is a miniature audio amplifier and very simple. Here I will give an audio amplifier schematic is very simple which only requires a few components only, can be seen under this scheme.

low power  amplifier  schematic
See from above scheme may occur to you, certainly cheap enough to make this amplifier and quite easy to make. The above simple audio amplifier circuit using an IC as the main amplifier and accompanied by other components. IC used is S1513, which requires a supply voltage ranging from 1.5 volts to 6 volts. And only 0.1 W output power with 4 ohm impedance. For a list components can be seen below.

Part list
C1 = 100nF
C2 = 100uF
C3 = 3n3F
C4 = 1uF
C5 = 1uF
U1 = S1513

Schematics for Mini and simple power amplifier Circuit Electronics
read more "Electronics Mini and simple power amplifier"

Electronics 50W car audio amplifier schematic

Circuit 50W car audio amplifier schematic schematics Circuit Electronics,
50W car <a href='' title='amplifier circuits'>amplifier</a> schematicsCar power amplifier uses SI1050GL IC as the main amplifier. The output power 50 Watt 8 ohm mono impedance. Up to 25 Volt DC voltage. with source voltage of this amplifier car battery has to work.

Minimum of 12 Volt battery voltage, less than a sound or audio is issued less than the maximum and less good. You can assemble  this circuit amplifier with a schema like this.

50W car <a href='' title='amplifier circuits'>amplifier</a> system

Part List

R1 = 100K

R2 = 1R

C1 = 2.2uF

C2 = 22uF
C3 = 100uF
C4 = 0.1uF

C5 = 100uF
U1 = SI1050GL
If you want to make stereo amplifier , you must required multiply the two of components.

Schematics for 50W car audio amplifier schematic Circuit Electronics
read more "Electronics 50W car audio amplifier schematic"

Electronics 1000W ICs audio amplifier with PA03

Circuit 1000W ICs audio amplifier with PA03 schematics Circuit Electronics,
This is a series of amplifiers are based on the most high-ic power that I have ever known. Because the output is issued up to 1000 watts with the impedance RL 4Ohm. Current supply 120mA, and 30A output current. Minimum input voltage of about 30V and a maximum voltage up to 150V. This is an audio amplifier that I have come across use ICs that maximum voltage up to 150V and output power up to 1000W , the scheme below gan.

1000W ICs <a href='' title='audio circuits'>audio</a> power amplifier

Part List


R1 = 10K

R2 = 10K

R3 = 220K

R4 = 0.18R 5W

R5 = 2.2R 2W

R6 = 0.18R 5W


C1 = 1uF

C2 = 1000uF

C3 = 68pF

C4 = 1000uF


L1 = 4MH


U1 = PA03

Schematics for 1000W ICs audio amplifier with PA03 Circuit Electronics
read more "Electronics 1000W ICs audio amplifier with PA03"

Electronics 450W Power amplifier

Circuit 450W Power amplifier schematics Circuit Electronics,

high power rangkaian amplifierBelow it is a circuit of power amplifiers with power output of 450 watts mono , amplifiers are also frequently used in the amplifier a high-power amplifier, which used in an event, in the field and the placed closed. Because this amplifier suitable for the woofer, fullrange speaker, and can also be fixed for the subwoofer speaker.

To further strengthen and maximize the amplifier ,its equalizer circuit also must be accurate, for electrolytic capacitors in equalizer ,voltage capacitors use 80V or more, and a capcity 20000uF upwards, so when the bass amplifier is high , the voltage is not lot of experience dropping. Diode bridge use a minimum of 35A, or adjust the current input voltage. If the equalizer has fulfilled the desire, the supply to the power amplifier.

450W <a href='' title='amplifier circuits'>amplifier</a> schematics


Schematics for 450W Power amplifier Circuit Electronics
read more "Electronics 450W Power amplifier"

Electronics Power amplifier for TV audio

Circuit Power amplifier for TV audio schematics Circuit Electronics,
In this amplifier circuit using IC TDA8944J as the main amplifier with dual-channel audio amplifier with 2 x 7W output power at 8 Ω impedance. And a minimum supply voltage of 9-18 Volts. In this ic contains two Bridge Tied Load or BTL amplifier.

The circuit is often found in audio amplifier in a series of television, besides TDA2003, TDA2006 and so forth. PCB for a series of amplifiers using IC TDA8944J is very compatible with all other types of IC in IC TDA894X family unit , and below is a schematics.

TV <a href='' title='audio circuits'>audio</a> amplifier

Schematics for Power amplifier for TV audio Circuit Electronics
read more "Electronics Power amplifier for TV audio"

Electronics 300W Subwoofer Power Amplifier

Circuit 300W Subwoofer Power amplifier schematics Circuit Electronics,
300W woofer subwoofer systemThis is an amplifier circuit that is formed from a transistor amplifier miraculous. This circuit is used in the speaker subwoofer with 300W maximum power on each side. To apply it, can be used in the room that is not too large, like the car. And the voltage needed between 25 to 42 Volt DC.

This is schematic of 300W subwoofer amplifier

subwoofer <a href='' title='amplifier circuits'>amplifier</a> circuit rangkaian skematic

Schematics for 300W Subwoofer Power amplifier Circuit Electronics
read more "Electronics 300W Subwoofer Power Amplifier"

Electronics TA8210AH Stereo Car Power Amplifier

Circuit TA8210AH stereo Car Power amplifier schematics Circuit Electronics,
IC TA8210AH By using this you can apply a series of audio power amplifier is the car audio system. In general, all the speakers in the car using a subwoofer speaker, and woofer. Because the car is not big room so the sound is being required is not too high.

Audio amplifier circuit can work at a minimum voltage 12-volt DC, if supplied under voltage 12-volt amplifier work will be less than the maximum. This amplifier output power up to 200W or 2 x 100W stereo with 8 ohm impedance.
200W car <a href='' title='amplifier circuits'>amplifier</a> schematic

Part List :



R1 =1K

R2 =50K trim

R3 =1K

R4 =50K trim

R5 =680R

R6 =680R

R7 =150K

R8 =2R2

R9 =2R2




C1 =1uF

C2 =1uF

C3 =47uF

C4 =47uF

C5 =100n/400V

C6 =220uF

C7 =220uF

C8 =100n/400V

C9 =100n/400V


Intregated Circuit



X2-3=in R


X2-1=in L

X1-1,X1-2=Out R

X1-3,X1-4=Out L
Schematics for TA8210AH stereo Car Power amplifier Circuit Electronics
read more "Electronics TA8210AH Stereo Car Power Amplifier"

Schematic Superb Power Amplifier using TDA7250 Circuit Diagrams

Circuit Superb Power amplifier using TDA7250 schematics Circuit Electronics,

This 2-channel hybrid IC is normally configured with TIP142/147 power darlingtons for its' output. For those who prefer to use power transistors instead, the TDA7250 can easily be converted. All that is required are a few transistors, 4 additional resistors and some rewiring.

This conversion centers mainly on changing the output section to a Sziklai.

Sziklai Output

In our IA502 on the right, drivers Q1,Q2 are 2SC2238 and 2SA968, and outputs Q5,Q6 are 2SA1216 and 2SC2922 respectively.

No instability problems were encountered from this conversion. After a period of run-in, the amplifier remained thermally stable.

Is this version worth the extra cost and effort?

If one is only interested in something basic, the TIP version would be sufficient. But if one is after sonic performance, I would recommend this version.

2SC2922/2SA1216 hardwired

the TDA7250 ic

Schematics for Superb Power amplifier using TDA7250 Circuit Electronics
read more "Schematic Superb Power Amplifier using TDA7250 Circuit Diagrams"

Schematic 2SJ113/2SK399 SEPP AB-40W stereo power amplifier, no feedback, the DC system Circuit Diagrams

Circuit 2SJ113/2SK399 SEPP AB-40W stereo power amplifier, no feedback, the DC system schematics Circuit Electronics,
MJ wireless experiment in 1992 and announced in June

MOS-FET power output stage, a simple voltage・Miller called the NFB minor loops in multiplied by a powerful, and put on overalls with the NFB, has achieved very low output impedance, the natural sound of the amplifier.

Lead chassis S4 (300 × 200 × 60) is used. Both sides in the handmade SHIMASHITA wood paneling.
Block on the chassis are amplified voltage capacitors and a small stage for those who for the power transformer and the radiator and looks imposing, but the real thing is compact and lightweight.
Input terminals and output terminals to a lot of effort SUPATORON.
At the bottom of the radiator board配SHI MOS-FET power output stage and to shorten the wiring, the gate入RENAKU series resistance does not even oscillation.
Just change a little wiring, the source follower circuit voltage circuits in the mirror can be changed.
Miller-voltage operating conditions of the basic design is satisfactory, the source follower to change to get high-quality sound.

Miller-voltage circuit

Miller-voltage circuit and, as shown in Figure 1, MOS-FET source follower circuit and facing each other, the zero-bias operation to add J-FET, multiplied by the output stage to return to the local circuit.

[Figure 1] The output stage of the library
J-FET drain side of the drive and a collector of Tr-stage gate MOS-FET, so it is high impedance.
Pch Nch of the J-FET drain and between the MOS-FET INBIDANSU low bias power are combined with V B.

Therefore, the drive signal from the current stage, I S, J-FET to the source of the flow resistance R S, J-FET source of the signal voltage V S to occur, MOS-FET to the source of power equal to V S V O voltage can be obtained.

J-FET drain side of the higher impedance Z D, the output impedance of Z O will be reduced, MOS-FET input capacity of Cis (all seen from the side of the gate capacity, and will include feedback capacity) to I see a higher frequency and lower Z D, Z O increases.

MOS-FET gate - source voltage V GS, at a maximum and not more than V B, the maximum drain current I D is limited in quantity, so the effect of preventing excessive current may have up to two out of The current limit action in the clip must be designed to SHIMAWANAI.
The MOS-FET, the threshold voltage V GS (th) g m and the highest transconductance is desirable.
Fortunately, switching for the rich in power MOS-FET, but the request was consistent with many.

The design of this machine

MOS-FET used in Hitachi 2SJ113/2SK399 to.
Figure 2 shows the transmission characteristics.

1A and the idling current I O and Figure 2 and V GS is the extent to 5V, V B of the V GS is about twice the 10V.

[Figure 2] 2SJ113/2SK399 V GS-I D characteristics of
V GS to take a maximum of 2SJ113/2SK399 the aforementioned principles of the V B is less than 10V.

V GS in the case of a 9V about 9A So I D, 2Ω load resistance of the output voltage is also available in 18V, low enough to bear the load impedance.

For the basic design of the circuit is shown in Figure 3.

[Figure 3] The basic design of this machine

Power transformer, the tango TOROIDARUTORANSU using the RS-3101, the output stage supply voltage V DD is about 32V.

I O V B significantly higher if you set it, I D at the current clip can be larger, while the MOS-FET to increase the amount of heat, P CH channels of loss over the amount of allowable because This machine, and I O is 1A.

[Figure 4] heat dissipation design

Table 1 from the standard table P CH = 100W (Ta = 25 ℃), T CH = 150 ℃, so

Heat inside the θ i resistors θ i = (T CH - T a) / P CH = (150 ℃ - 25 ℃) / 100W = 1.25 ℃ / W.

DENKA TO-3P heat sheet using the MOS-FET and the thermal resistance between the radiator, Contact thermal resistance thermal insulation resistance θ c + θ s = 0.75 ℃ / W.

Below is a circuit diagram of the heat conduction.

P CH = V DD I C = 32V × 1A = 32W, so Radiator will be allowed to seek maximum temperature T f,

T f = T CH - P CHics =150℃ -32W×(1.25℃/W +0.75℃/W ) = 86℃

Ta ambient temperature of the radiator in the case of 50 ℃, The maximum permissible radiator heat resistance,

θ f = ( T f - T a )/ P CH = ( 86℃-50℃ )/32W =1.125℃/W

Figure 4 design radiating from the radiator to keep the temperature must be below 86 ℃.
Therefore, the radiator of a flexible TF1212 (122x120 × 40) in four pieces, MOS-FET is attached by a single, open-style chassis and put on.

Bias circuit as shown in Figure 5, V B less than 1 ~ 2V zener diode voltage and low anti-adjustable instrument (VR) has been able to adjust.

[Figure 5] Bias Circuit

The circuit and cause a bad contact VR, I O is on the rise as a dangerous, VR is reliable in use. CRD Diode, SEMITEC Japan = E102 0.88 - 1.32 mA, 10V

The constant voltage bias circuitry to operate a minimum of about 2mA current I L.

Miller-voltage circuits used in the local feedback 2SJl08/2SK370 of the J-FET I DSS 5.5mA is ranked GR, g m and the same amount if I DSS, and other forms of J-FET is also available.

The output stage for a full swing to V S necessary, to afford to ± 30V, R S at the time that I S 2.2kΩ is in full swing is ± 14mA.
When you, 2SJl08/2SK370 current flowing through the gate area covered Tr, is the gate to the low-impedance does not affect operation.

Tr stage of the drive for the operating current I S I S I SO that is half the 7mA, drive circuit and locally Biasing stage of the J-FET feedback circuitry necessary to operate because of the current sources of supply, drive stage Tr I DO idling current of the

I DO > I L + I DSS + I SO I DO> I L + I DSS + I SO
= 2mA+5.5mA+7mA = 2mA +5.5 mA +7 mA
=14.5mA = 14.5mA

'91 Of the amplify circuit voltage in the February issue of its MOS-FET DARINTONANPU INBATEDDO as well as two-stage amplification of the no-return.

FET first dan level of the output stage with zero bias 2SJ108/2SK370 behavior is the same.

Figure 3 is a constant,
I DO = ( R DI DSS - V BE ) / R E I DO = (R D I DSS - V BE) / R E
=(1kΩ×5.5mA-0.6V)/0.27kΩ = (1kΩ × 5.5mA-0.6V) / 0.27kΩ
=18mA = 18mA
Thus, the above conditions are satisfied.

If I DSS is a small increase in R S and will need constant change.

In addition, R S of the increase can be, if滅RASHITA Conversely, 1.8kΩ below the oscillator to the output stage.
NFB also put to the Ministry of voltage amplification, or as the output stage of the oscillation Darlington to make it easier to connect.
Such circuits, in order to prevent oscillation, MOS-FET and the gate necessary to insert a resistance in series there.

The circuit of the machine

All of the library circuit is shown in Figure 6.

[Figure 6] The circuit of the machine

Amp circuit parts

Change of source follower

Part of the power circuit

The amplification of the first dan level voltage, FET to cover the cascode-voltage connection was made.

To amplify the power of the voltage, the power to reduce noise and crosstalk, CR put filters.

To prevent oscillation, MOS-FET's drain and capacitor ground connection between the wiring to a minimum.
This type of capacitor used in a significant impact on the stability of this machine 1μF use of multilayer ceramic capacitors, in a square wave output waveform was able to reduce ringing.

In making this standard to guarantee performance, Tr KONPURIMENTARIPEA and keep FET using a commercially available, and no resistance to the 5 percent level used in the selection.
A pair of strict screening device, and using high-precision resistance, to get the balance of push-pull, you can further reduce distortion.

The machines used in the standard device is shown in Table 1.

In addition, the unit of the standard elements of a possible substitute.

[Table 1] FET, Tr standards

Maximum Ratings (Ta = 25 ℃, * Tc = 25 ℃)

Electrical Characteristics (Ta = 25 ℃)




T j


g m

C is

Electrodes connected
Model name












-2.6~ -20














* P CH


V GS(th)

g m

C is












-2~ -5















T j

f T

C ob




h FE























T j

f T

C ob




h FE




















The production of this aircraft

A4-size chassis lead the S4 (300 × 200 × 60).

Impossible without wiring and components acrobatics on the use of the mounting, as long as stylized as a result of how the parts are in place, but not from the beginning rather than in accordance with such style, the best components and circuitry It is thought to want a place. High-current circuit in order to shorten the wiring, 22000μF blocks of storage capacitors on the inside of the chassis.

Processing of the chassis, radiator and cooling radiator for the better part of the mounting, to increase stiffness of thick reinforced with aluminum angle.

YASURI chassis in the welding marks from flat paint and Trim can be

Decoration on the front of the word processor in a black plastic sheeting was printed in gold ribbon stickers on their own.

For the board, copper foil for printed circuit board wiring can not be used as a vapor.
As a result of the library board, as in Figure 7, the bull's-eye of the copper foil substrate in the etching solution to remove the lead wire through a hole in the expansion of 2mm in diameter, and bring out the wiring in place of a single wire fault of 0.8mm thickness Strange.

[Figure 7] of the library board

The upper parts of the board layout

zu7.gif (24134 bytes)

Place the bottom part of the board

Change of source follower

zu7u.gif (23743 bytes)zu7s.gif (12518 bytes)
MOS-FET from the board to speed up the wiring, the board placed part of the mounting position, I sent a particular concern.

Tr two-stage during the drive, angled aluminum heat sinks are attached to the tie, the heat of the earth plate connected to the substrate, and the chassis may not have any contact.

FET complementary characteristics , so the thermal drift, it is binding, so the heat on this machine is not binding.

Upper and lower parts of the substrate is mounted on both sides, and are cross-wired to the stereo, not making a mistake when you have good circuit diagram and to see that match.

Power supply circuit, the capacitor blocks from the terminal Rch Lch and wiring into two strains, and 100Ω equalizer voltage amplifier attached to the plate to lag, the output of the idling current stage of the resistance to check the terminal block 0.47Ω Mounted on.

The output signal Q8, Q9 and the gate of 2.2kΩ extracted from the Earth's is a logical.
Therefore, Q10, Q11 from the source of Q8, Q9 Hye-wiring of the gate, which are then wired to the output pins.

But from the supply side of the Earth Hye 2.2kΩ, and the output pins and wiring.

Rectifier diode from the wiring to emit intense RIPPURUNOIZU other引KI回SHIMASU do not interfere with wiring.

MOS-FET gate of the current-carrying wires and open and the input capacity is in charge of the gate voltage to drain excessive current to flow, so beware of destruction.

Adjustment of the machine

Before the adjustment of the resistance VR 1 and VR 2 to leave the minimum value.

Turn the first time, in case of emergency drain and power MOS-FET 10Ω10W between the need to connect to the resistance.

Turn the output within ± 2V DC voltage, 10Ω peers verify voltage is less than 10V.

10Ω would remove the anomaly, the wiring back to normal.

The first adjustment, and idling for 1A current, VR 2 to adjust the voltage of 0.47V at both ends 0.47Ω.

If the VR 2, it is up to 0.47V If the VR 2 in the series with less than 1 ~ 2kΩ resistance in the case, contrary to 0.47V as VR 2 more than the minimum if the HZ-HZ-9L zener diode 7L exchange.

After idling 0.47Ω current settings and leave a short circuit.

DC output voltage to 0V and then to adjust the VR 1, but the power of the state暖MAっcold and heat until a stable condition change DC voltage output to 0V in any state. The machines fluctuation band around the center of the 0V.

Turn the VR 1 to increase output if the DC voltage, Q 1 source of 390Ω

After more than a measurement of adjustment, and later was able to get the property.

Changes to the source follower circuit

Lower SOSUFO If you compare the change in voltage that Miller was going to show excellence, excellence is fundamental to the circuit, the source follower of the great qualities who is also my best MASHITA.

Miller FOROWAHE voltage changes from the source, Figure 6, Figure 7, as shown in the return of local resistance to remove the FET switching can be a simple, so one can enjoy as much of the amplifier.

After the changes increase Idling a little current, so the re-adjustment is required.

In addition, changes to the circuit in the switch is no more acceptable.

The longer the oscillation circuit will be easier if the switch is running a poor contact and damage the cause of switching from the speakers.

In addition, a source follower of the voltage amplifier if you want to change the mirror, mirror voltage as the above-mentioned constraints must be met.

The characteristics of this machine

Figure 8 characteristics and the frequency of the Figure 9 crosstalk characteristics of the source and the voltage follower without a difference in the mirror, and accepted the good characteristics of the vocal cord is in the region.

RESUBONSU the high-growing region because of the high-frequency signals of the MOS-FET input current capacity can be passed through the gates - the source of signal voltage between the decrease in cost.

[Figure 8] frequency characteristics.
zu8.gif (14832 bytes)

[Figure 9] characterization of crosstalk
zu9.gif (17063 bytes)

Figure 10 is characteristic of the distortion, and frequency for each individual to move parallel to the low-voltage Mirror, low-frequency effects of a localized because of the high return rate is a low distortion.

[Figure 10] distortion characteristics
zu10.gif (21832 bytes)

Figure 11・damping factor characteristic of the low-frequency BORUTE JIMIRA If there are more than 1,000 from 600Hz to 100kHz while much is falling in a straight line.
The cause, MOS-FET input will increase capacity and frequency for the local decrease in the amount of feedback.
Meanwhile, the case source follower, about 20 in the regional auditory zone is nearly constant. This is like a personality characteristics of each other's differences, which divide the sound quality is a factor.

[Figure 11] damping factor characteristics・
zu11.gif (18643 bytes)

Then resist Load by 10kHz square wave output waveform of the load and capacity are shown in the photos.

Enlarge to rise again to display the waveform, the ringing is legible.

10kHz square wave output waveform Photo
SOSU・FOROWA Miller voltage・

8Ω load 4Vp-p

8Ω load 4Vp-p

sf8.gif (34662 bytes)vm8.gif (46892 bytes)

0.1μF load

0.1μF load

sf01.gif (35640 bytes)vm01.gif (36468 bytes)

0.47μF load

0.47μF load

sf047.gif (38284 bytes)vm047.gif (35653 bytes)

8Ω +0.1 μF load 4Vp-p

8Ω load 55Vp-p

sf801.gif (36849 bytes)vm55.gif (34460 bytes)
Miller-source voltage follower and stability in both high-capacity load is not on the oscillation.
High stability and the improvement of property ambivalent relationship with, is a difficult balance.

The high-range aircraft to more than necessary that the property did not extend to higher depreciation was available taxis.

ON-OFF at the time of supply shocks 0.5Vp-p less noise and lower the residual noise Rch 140μV, Lch, and it also reduces the 130μV, and silence the cry of power transformer in the extra care.

The temperature of the radiator, but if you do not mind the location of the ventilation, can not be touched by hand and the heat is not enough.

The sound quality of the natural voltage moist Miller faction, the source follower and a faction a spectacular reduction of the thick, and to insist on individuality, both of which are difficult to discard, the悩MIMASU choice, but only if producers Can enjoy luxury.

Schematics for 2SJ113/2SK399 SEPP AB-40W stereo power amplifier, no feedback, the DC system Circuit Electronics
read more "Schematic 2SJ113/2SK399 SEPP AB-40W stereo power amplifier, no feedback, the DC system Circuit Diagrams"