Hello
For long time i have designed with a friend Mosfet amp, the amp is working very stable with natural sound, railvoltage is +/- 90 V
I have see the N Channel schematic from QUASI and want modify my Mosfet Amp.
Id like to replace IRFP 9240 with IRFP 240 to quasi complementary output stage
I have replace IRFP 9240 with IRFP 240 in schematic , could this work only with N Devices ?
If not what is important to change or to add for stable working ?
For long time i have designed with a friend Mosfet amp, the amp is working very stable with natural sound, railvoltage is +/- 90 V
I have see the N Channel schematic from QUASI and want modify my Mosfet Amp.
Id like to replace IRFP 9240 with IRFP 240 to quasi complementary output stage
I have replace IRFP 9240 with IRFP 240 in schematic , could this work only with N Devices ?
If not what is important to change or to add for stable working ?
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If you have to ask I have to say that you aren't qualified/experienced enough to make the changes to such a powerful amp.
The schematic you posted is barely readable, from what little I can make out it looks like it will immediately set on fire when you apply power, with the modifications you have made. As the whole bottom bank of MOSFETs goes into saturation.
Why modify the amp if it's working fine? You will not gain any benefit whatsoever simply by using all n-channel devices.
The schematic you posted is barely readable, from what little I can make out it looks like it will immediately set on fire when you apply power, with the modifications you have made. As the whole bottom bank of MOSFETs goes into saturation.
Why modify the amp if it's working fine? You will not gain any benefit whatsoever simply by using all n-channel devices.
The Problem is the P Channel Mosfet, its not possibile to get High Power high Voltage P Mosfet equal. to N Channel Mosfet for good results in an audio amplifier.
First I want replace P Channel Mosfets with N Devices in the schematic.
If its working (stable) with N Devices i want upgrade the N Channel Mosfet amp for high Voltage > 100 V and high power.
Can you help me
First I want replace P Channel Mosfets with N Devices in the schematic.
If its working (stable) with N Devices i want upgrade the N Channel Mosfet amp for high Voltage > 100 V and high power.
Can you help me
@richie00boy ....1500W into 2 ohms if you double the number of MOSFETs.
ok but i think i need much higher Rail Voltage > +/- 90 V for 1500W into 2 Ohms and some people told me more than +/- 100 V Rail Voltage and the Mosfets will destroyed. How much could be the Rail Voltage with mosfets IRFP 9240 and IRFP 240 to upgrade this amp 1500W 2 ohms?
@ongthrow.... to add a driver stage after the VAS the case of your VAS topology does not allow
Can you help me and add the important driverstage after the VAS for quasi complementary into schematic because i am not qualified/experienced enough to make working changes
Thank you
ok but i think i need much higher Rail Voltage > +/- 90 V for 1500W into 2 Ohms and some people told me more than +/- 100 V Rail Voltage and the Mosfets will destroyed. How much could be the Rail Voltage with mosfets IRFP 9240 and IRFP 240 to upgrade this amp 1500W 2 ohms?
@ongthrow.... to add a driver stage after the VAS the case of your VAS topology does not allow
Can you help me and add the important driverstage after the VAS for quasi complementary into schematic because i am not qualified/experienced enough to make working changes
Thank you
+/-90 Volts will easily give you 1500 Watts into 2 ohms. Even accounting for circuit losses.
In order to do this though you will need a 3kW to 4kW transformer and plenty of filter capacitance. Maybe about 400,000uF. That is per channel! If you want to be able to do this on a steady basis, you would probably need 30+ pairs of output devices. Again per channel. Also a very big soft start circuit with a very large relay! Also even if you did build it this way you would need a 3.2kW circuit to power it!! That's a 30Amp circuit at 110V and 15Amp at 220V!!!!!!!!
Why do you need 1500W into 2 ohms? Is this a PA amp?
Thanks, Don
In order to do this though you will need a 3kW to 4kW transformer and plenty of filter capacitance. Maybe about 400,000uF. That is per channel! If you want to be able to do this on a steady basis, you would probably need 30+ pairs of output devices. Again per channel. Also a very big soft start circuit with a very large relay! Also even if you did build it this way you would need a 3.2kW circuit to power it!! That's a 30Amp circuit at 110V and 15Amp at 220V!!!!!!!!
Why do you need 1500W into 2 ohms? Is this a PA amp?
Thanks, Don
@ Don s
The amplifier is working with 4 Ohms very good, i dont have test 2 Ohms with full output power, and before i make new pcb i want inform me.
Its better to do it with N devices because its easy to find High Power High Voltage N Mosfet devices.
@leolabs yes thats right with BJT. You can build with BJTs very cheap amplifier but the sound with BJT is not so good.
The Sound with Mosfet Devices is another, better like a tube amplifier so i need help to make changes in schematic for N Devices.
And amplifiers with BJTs you can find enough in the market from China build for the big companies in USA
@ retrosong .... here is new schematic
This Mosfet amp with IRFP 9240 and IRFP 240 in output stage is working good and stable with very low bias power.
I have removed in schematic output stage IRFP 9240 and replaced with N devices IRFP 240. Could this work ?
If not who can help me to drive only N devices in output stage?
regards from Germany
The amplifier is working with 4 Ohms very good, i dont have test 2 Ohms with full output power, and before i make new pcb i want inform me.
Its better to do it with N devices because its easy to find High Power High Voltage N Mosfet devices.
@leolabs yes thats right with BJT. You can build with BJTs very cheap amplifier but the sound with BJT is not so good.
The Sound with Mosfet Devices is another, better like a tube amplifier so i need help to make changes in schematic for N Devices.
And amplifiers with BJTs you can find enough in the market from China build for the big companies in USA
@ retrosong .... here is new schematic
This Mosfet amp with IRFP 9240 and IRFP 240 in output stage is working good and stable with very low bias power.
I have removed in schematic output stage IRFP 9240 and replaced with N devices IRFP 240. Could this work ?
If not who can help me to drive only N devices in output stage?
regards from Germany
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