Mosfet Amps | Electronic Project Circuits

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Mosfet Amplifier OTL 100W by K1058,J162

This includes a 220uF capacitor and two diodes to slow down the switch-on to reduce the output thump as the output capacitor charges through the speaker. This is not essential, depending on speaker sensitivity, with my own speakers there is just an unobtrusive low frequency sound at switch-on. With other applications such as a bi-amp or tri-amp system with active crossover filters, this addition may become more useful to avoid low frequencies reaching high frequency speaker drivers. It may also have some point if a high sensitivity speaker is used, so it makes sense to include it in this low noise version.

Be the first to comment - What do you think? Posted by admin - April 30, 2008 at 11:57 am

Categories: mosfet amp Tags: 100 watt amplifier, J162, K1058, Mosfet amps

Power amplifier 65W with HEXFET IRF540, IRF9540

A medium power amplifier that is characterized by a lot of good sound quality, but simultaneously is very simple in the construction. Him uses, enough time in my active loudspeakers. In his output stage exist the very good FET transistors, technology HEXFET, transistor which are controlled by voltage and no by current as the classically bipolar transistors. The circuit has symmetrical designing, resolving thus the harmonic distortion problem. All the transistors that are used in the circuit are simple and they exist in big clearings in the market. The pairs of differential amplifiers Q1-2 and Q3-4 should be matched between them and near the one in the other….

Part List

R1-15-16-21-22-17-18=1Kohm R33=68ohm 5W Q1-2=BC550C [matched]
R2=47Kohm R35-36=6.8ohm 1W Q3-4=BC560C [matched]
R3-4=10Mohm TR1=1Kohm trimmer Q5=BC560C
R5-6-13-14=1.2Kohm TR2=1Mohm trimmer Q6=BC550C
R7-12=47ohm C1=2.2uF 63-100V MKT Q7-11=BD140
R8-9-10-11=22ohm C2=1nF 100V MKT Q8-9-10=BD139
R19=82ohm C3-4=2.7nF 100V MKT Q12=IRF9540
R20=22Kohm C5=330pF ceramic or mylar Q13=IRF540
R23-26=56ohm C6-7=100uF 16V F1-2=Fuse 2.5A Fast
R24=2.2Kohm C8=1uF 100V MKT L1=see text [2]
R25=560ohm C9-11-12=100nF 100V MKT J1= 2pin connector 2.54mm step
R27-30=150ohm C10-13=470uF 63V
R28-29-31-34=15ohm C14=33nF 100V MKT Q8-10-11-12-13 on Heatsink
R32=150ohm 5W D1-2=LED RED 3mm [see text] [1] All the resistors is 1/4W 1% except quote differently

Read More Source:http://users.otenet.gr/~athsam
Thank you.

Be the first to comment - What do you think? Posted by admin - September 6, 2007 at 8:50 pm

Categories: mosfet amp Tags: Hexfet power mosfet, IRF540, IRF9540, Mosfet amps

Basic MOSFET amplifier 100W with 2SK1530,2SJ201

I propose you here a basic MOSFET amplifier. Output power is +/- 100 Wrms under 8 ohms or +/- 160 Wrms under 4 ohms.
Due to the circuit simplicity, distortion is +/- 0.1 %. Bandwidth at -3 db is from 4 Hz to 96 Khz, it is limited by C1, R1, C2 and R2.
Transistors T1 and T2 makes a first differential stage, current source of +/- 1 mA is set by R3. In the upgraded version, current source is more efficient in stability. P1 allows a fine tuning of DC voltage at amplifier’s output. Place P1 at it’s half value for first power up, then turn it slowly for a lowest DC output voltage. Use a first quality compoment.

Part
C1 = 2,2 µF MKP, MKT 100 V
C2 = 330 pF ceramique 50 V
C3 = 100 nF MKP, MKT 100 V
C4 = 100 µF 40 V electro-chimique
C5, C6 = 18pF ceramique 50 V
C7 = 100 nF MKP, MKT 250 V (C8 = 47µF 100 V)
R1, R3 = 47 K (R3 = 330 – 470 Ohms)
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 (R17 = 1 K R18, R19 = 10K)
T1, T2, T9,T10 = 2N5401, ZTX558, BC556B (attention au brochage different – take care for pin layout)
T3, T4 = BF470, MJE350, 2SB649
T5, T6 = BF469, MJE340, 2SD669
T7 = IRFP240, 2SK1530, 2SJ162, BUZ900DP, BUZ901DP (attention au brochage different – take care for pin layout : GDS GSD)
T8 = IRFP9240, 2SJ201, 2SK1058, BUZ905DP, BUZ906DP (attention au brochage different – take care for pin layout : GDS GSD)
P1 = 100 ohms (25 tours – 25 turns)
P2 = 2K5 (25 tours – 25 turns)
F1, F2 = 3 A T