Except for Nelson Pass 70W Class A, which I never listened to, I'm not aware of any audio amp using IRF mosfets which was considered good or exceptional in audio quality.
OTOS, there are several amps using Toshiba's lateral mosfets which got excellent reviews.
So maybe the LME front end would sound better with them.
OTOS, there are several amps using Toshiba's lateral mosfets which got excellent reviews.
So maybe the LME front end would sound better with them.
Hi
I know at least one exception for IRF mosfets: the AMB beta 24 power Amp: The β24 Fully-differential Power Amplifier
It uses mosfets IRFP140N/IRFP9140N.
I had the chance to listen to one of them from a DIY member (very very nice amp built by the way) with a group of peoples we were very pleased with what we heard
Fab
LM49830 with IRFP9240/240
Hi together,
I'm from germany and I red this threat because I want to build an amplifier with the LM49830 gate driver and IRFP240 / 9240 Mosfets because they're very cheap to get.
The circuit I want to use is in the attachment, can I easily change the mosfets to the IRFP240/9240 or do I have to change any resistors?
Has anyone build exactly this circuit and experiences with it?
best regards
Bernhad Waechter
P.S. please don't mind about my bad english ;-)
Hi together,
I'm from germany and I red this threat because I want to build an amplifier with the LM49830 gate driver and IRFP240 / 9240 Mosfets because they're very cheap to get.
The circuit I want to use is in the attachment, can I easily change the mosfets to the IRFP240/9240 or do I have to change any resistors?
Has anyone build exactly this circuit and experiences with it?
best regards
Bernhad Waechter
P.S. please don't mind about my bad english ;-)
Attachments
You should read mail #480, where they did use those IRF mosfets and didn't like them.
If I'm not wrong that design you show is from Bob Cordell's book, isn't it?
I was checking the Anthony Holton amplifier Nx200 and it has two Toshiba Mosfets with voltage ratings of +/-55 volts and its rated at 110watts into 8 ohms and 180 into 4 ohms..
But I see other modules with these LME chips and with the same mosfets able to get the similar ratings with four Mosfets. Psu voltage considering the same what is that difference... seems strange with the anthony amps is that magic...
But I see other modules with these LME chips and with the same mosfets able to get the similar ratings with four Mosfets. Psu voltage considering the same what is that difference... seems strange with the anthony amps is that magic...
one must consider the temperature de-rated SOAR of the output stage to determine whether a certain loading from a specific PSU can be reliable.
This requires the heatsink and performance duty and the output devices and the PSU capacity and the ambient temperature, all to be taken into account.
One cannot just look at the output devices in isolation.
One must consider the whole system including what type of listening is done, the performance duty.
This requires the heatsink and performance duty and the output devices and the PSU capacity and the ambient temperature, all to be taken into account.
One cannot just look at the output devices in isolation.
One must consider the whole system including what type of listening is done, the performance duty.
I am planning to Build a 6 channel amp but something a new try for highend Multichannel class A amp.
Im trying to get 50Watts Rms into 8 ohms for Class A and 100RMS into 8 ohms in AB.
I am ready to use any amount of capacitance for the amp. I have checked with the Toroidal Company for the trafo for 2KVA with secondary 35x2.
I need some help reg the amps design
1. Im thinking to use Toshiba Mosfets Output stage
2. I want to use 1 pair of Mosfets per channel
3. Need pretty high Damping factor so output impedance has to be pretty low.
4. These are the heatsinks that I would be using http://2.imimg.com/data2/RG/AW/MY-/2.pdf They are industrial grade and the specification is very promising. When they say they can dessipate 120watts at the ambient temp 25 degrees they do that since they are industrial grade. They are sold per meter. I can get accordingly on how many meters are required im thinking of going with 1 meter based on what temperature that needs to be dissipated.
5. Each side of the amp consists of 3 channel.
6. Expected devices I believe for the specification for Class A
for 50watts into 8 ohms the actual Transformer rating to be 200VA so for all 6 channels Im expecting 1200VA Toroidal. I have checked on the pricing front the difference between 1.2 Kva and 2Kva is just 35 USD so thought to go with 2KVA but if its really required I think we can go with that trafo.
7. Psu capacitors wise I have sources for 10000uf and 20000uf caps I can buy 10 of these or as required there has been long thread that how much capacitance required for the PSU.
8. Im thinking of using a soft start for this amp. Which brand is recommended any model in specific.
9. I would be using a switch for each channel for either to be in class A or AB.
10. There will be Elna silmic2 for electrolytic caps in between.
11. What diodes to be used i dont think MUR 860 can withstand for that high current.
12. I saw this heatsink in of the catalogue of industrial heatsinks. http://hifi-profi.ru/components/com_virtuemart/shop_image/product/Plinius_SA_103_4dd40747aad77.jpg
Its used in plinius amps.
please guys help me in deciding how to take it from here...
Im trying to get 50Watts Rms into 8 ohms for Class A and 100RMS into 8 ohms in AB.
I am ready to use any amount of capacitance for the amp. I have checked with the Toroidal Company for the trafo for 2KVA with secondary 35x2.
I need some help reg the amps design
1. Im thinking to use Toshiba Mosfets Output stage
2. I want to use 1 pair of Mosfets per channel
3. Need pretty high Damping factor so output impedance has to be pretty low.
4. These are the heatsinks that I would be using http://2.imimg.com/data2/RG/AW/MY-/2.pdf They are industrial grade and the specification is very promising. When they say they can dessipate 120watts at the ambient temp 25 degrees they do that since they are industrial grade. They are sold per meter. I can get accordingly on how many meters are required im thinking of going with 1 meter based on what temperature that needs to be dissipated.
5. Each side of the amp consists of 3 channel.
6. Expected devices I believe for the specification for Class A
for 50watts into 8 ohms the actual Transformer rating to be 200VA so for all 6 channels Im expecting 1200VA Toroidal. I have checked on the pricing front the difference between 1.2 Kva and 2Kva is just 35 USD so thought to go with 2KVA but if its really required I think we can go with that trafo.
7. Psu capacitors wise I have sources for 10000uf and 20000uf caps I can buy 10 of these or as required there has been long thread that how much capacitance required for the PSU.
8. Im thinking of using a soft start for this amp. Which brand is recommended any model in specific.
9. I would be using a switch for each channel for either to be in class A or AB.
10. There will be Elna silmic2 for electrolytic caps in between.
11. What diodes to be used i dont think MUR 860 can withstand for that high current.
12. I saw this heatsink in of the catalogue of industrial heatsinks. http://hifi-profi.ru/components/com_virtuemart/shop_image/product/Plinius_SA_103_4dd40747aad77.jpg
Its used in plinius amps.
please guys help me in deciding how to take it from here...
Last edited:
Rhyt,
judging by the questions you are asking and the proposals you are planning, you don't have a clue about what your are trying to achieve. You can't even write the brief. What will happen when you start to write the specification?
Find some good sites that explain ClassA.
Try Pass and ESP as starters.
judging by the questions you are asking and the proposals you are planning, you don't have a clue about what your are trying to achieve. You can't even write the brief. What will happen when you start to write the specification?
Find some good sites that explain ClassA.
Try Pass and ESP as starters.
Hi Andrew Im very new for the discrete designs. I have studied Electonics and comm engg 12 years ago and didnt touch anything after that looks like i need to revise the concepts.
I agree that the specifications are not formal but what I know about class A is it amplifies the signal symmetrically accurate and will have more fidelity with only 25% efficient when compared with AB.
For the questions that I asked..
I need some help reg the amps design
1. Im thinking to use Toshiba Mosfets Output stage
Many have said using these will give better output quality. I agree that if designs are good any mosfet will will good quality but when good amps have used it we can go with it.
2. I want to use 1 pair of Mosfets per channel
I didnt want more class A power happy with 50watts
3. Need pretty high Damping factor so output impedance has to be pretty low.
I have checked out on couple of sites that damping factor is very much dependent on the output impedance and hence low factors are required to drive 10 inch drivers efficiently.
4. These are the heatsinks that I would be using http://2.imimg.com/data2/RG/AW/MY-/2.pdf They are industrial grade and the specification is very promising. When they say they can dessipate 120watts at the ambient temp 25 degrees they do that since they are industrial grade. They are sold per meter. I can get accordingly on how many meters are required im thinking of going with 1 meter based on what temperature that needs to be dissipated.
> I have contacted an Aerospace and Defence equipment supplier for whom I have approached for some heatsink guidance ( he was my friend ) he said you can go according to the specification no need to have more headroom as the heatsinks are Defence and Aerospace. I found one model where Passlabs has used it.
5. Each side of the amp consists of 3 channel.
> Since its a multichannel amp so that we can have 3 on one side and 3 on other
6. Expected devices I believe for the specification for Class A
for 50watts into 8 ohms the actual Transformer rating to be 200VA so for all 6 channels Im expecting 1200VA Toroidal. I have checked on the pricing front the difference between 1.2 Kva and 2Kva is just 35 USD so thought to go with 2KVA but if its really required I think we can go with that trafo.
> since the efficiency of the Class A amp is 25% thought to have the transformer accordingly like 4 times the power on the laod. But I see people using bigger ratings like 6 times.
7. Psu capacitors wise I have sources for 10000uf and 20000uf caps I can buy 10 of these or as required there has been long thread that how much capacitance required for the PSU.
> I see some of the passlab diy amps like F3 having 360,000uf used. Maybe i thought its required for class A for very smooth power source.
8. Im thinking of using a soft start for this amp. Which brand is recommended any model in specific.
> I see some modules which are having softstart since the transformer is in KiloWatts.
9. I would be using a switch for each channel for either to be in class A or AB.
> I have seen this feature in Plinius Amplifier where the user can switch from class A to Class AB. I think he is switching the bias resistor with that switch.
10. There will be Elna silmic2 for electrolytic caps in between.
> Nelson Pass said they sound best for solidstate wherever they were used and even people who have modded their equipment said they sound good.
11. What diodes to be used i dont think MUR 860 can withstand for that high current.
> I got MUR860 for the chipamps but I know they cant sustain for heavy current flow so need a higher verison.
12. I saw this heatsink in of the catalogue of industrial heatsinks. http://hifi-profi.ru/components/com_virtuemart/shop_image/product/Plinius_SA_103_4dd40747aad77.jpg
> was a dream to own Plinius but atleast can build a good mosfet amp and have the similar heatsinks to look something like that...
Im sorry if my specifications were wrong Initially thought to go with the Aussie amplifier Modules or http://connexelectronic.com/images/500W LME49810 Audio Amplifier with Heatsink.JPG
and recap with decent caps.
I dont know about the specifcation 1Apk,2Apk and what this mean is this about current in load or bias current?
I am very new to discrete please guide me. Im considering these books to read Amazon.com: High-Power Audio Amplifier Construction Manual (9780071341196): G. Randy Slone: Books since I have some engineering background i think i can read it faster and understand it quick..
In the mean time please guide me.
I agree that the specifications are not formal but what I know about class A is it amplifies the signal symmetrically accurate and will have more fidelity with only 25% efficient when compared with AB.
For the questions that I asked..
I need some help reg the amps design
1. Im thinking to use Toshiba Mosfets Output stage
Many have said using these will give better output quality. I agree that if designs are good any mosfet will will good quality but when good amps have used it we can go with it.
2. I want to use 1 pair of Mosfets per channel
I didnt want more class A power happy with 50watts
3. Need pretty high Damping factor so output impedance has to be pretty low.
I have checked out on couple of sites that damping factor is very much dependent on the output impedance and hence low factors are required to drive 10 inch drivers efficiently.
4. These are the heatsinks that I would be using http://2.imimg.com/data2/RG/AW/MY-/2.pdf They are industrial grade and the specification is very promising. When they say they can dessipate 120watts at the ambient temp 25 degrees they do that since they are industrial grade. They are sold per meter. I can get accordingly on how many meters are required im thinking of going with 1 meter based on what temperature that needs to be dissipated.
> I have contacted an Aerospace and Defence equipment supplier for whom I have approached for some heatsink guidance ( he was my friend ) he said you can go according to the specification no need to have more headroom as the heatsinks are Defence and Aerospace. I found one model where Passlabs has used it.
5. Each side of the amp consists of 3 channel.
> Since its a multichannel amp so that we can have 3 on one side and 3 on other
6. Expected devices I believe for the specification for Class A
for 50watts into 8 ohms the actual Transformer rating to be 200VA so for all 6 channels Im expecting 1200VA Toroidal. I have checked on the pricing front the difference between 1.2 Kva and 2Kva is just 35 USD so thought to go with 2KVA but if its really required I think we can go with that trafo.
> since the efficiency of the Class A amp is 25% thought to have the transformer accordingly like 4 times the power on the laod. But I see people using bigger ratings like 6 times.
7. Psu capacitors wise I have sources for 10000uf and 20000uf caps I can buy 10 of these or as required there has been long thread that how much capacitance required for the PSU.
> I see some of the passlab diy amps like F3 having 360,000uf used. Maybe i thought its required for class A for very smooth power source.
8. Im thinking of using a soft start for this amp. Which brand is recommended any model in specific.
> I see some modules which are having softstart since the transformer is in KiloWatts.
9. I would be using a switch for each channel for either to be in class A or AB.
> I have seen this feature in Plinius Amplifier where the user can switch from class A to Class AB. I think he is switching the bias resistor with that switch.
10. There will be Elna silmic2 for electrolytic caps in between.
> Nelson Pass said they sound best for solidstate wherever they were used and even people who have modded their equipment said they sound good.
11. What diodes to be used i dont think MUR 860 can withstand for that high current.
> I got MUR860 for the chipamps but I know they cant sustain for heavy current flow so need a higher verison.
12. I saw this heatsink in of the catalogue of industrial heatsinks. http://hifi-profi.ru/components/com_virtuemart/shop_image/product/Plinius_SA_103_4dd40747aad77.jpg
> was a dream to own Plinius but atleast can build a good mosfet amp and have the similar heatsinks to look something like that...
Im sorry if my specifications were wrong Initially thought to go with the Aussie amplifier Modules or http://connexelectronic.com/images/500W LME49810 Audio Amplifier with Heatsink.JPG
and recap with decent caps.
I dont know about the specifcation 1Apk,2Apk and what this mean is this about current in load or bias current?
I am very new to discrete please guide me. Im considering these books to read Amazon.com: High-Power Audio Amplifier Construction Manual (9780071341196): G. Randy Slone: Books since I have some engineering background i think i can read it faster and understand it quick..
In the mean time please guide me.
Right back at your first statement "i want 50W of ClassA" & " I will use 1pr of mosFETs". These are incompatible statements. They have become a nonsensical specification.
You need to go back further and state a brief, with no technical detail.
Like
I want to build a ClassA amplifier to drive "named speaker".
Then you will get some help in preparing a specification.
At the moment you appear to know nothing about ClassA.
Go and do a lot of reading.
Your brief may become.
I can't afford a ClassA amplifier, I have now decided I want a good audio quality amplifier.
You need to go back further and state a brief, with no technical detail.
Like
I want to build a ClassA amplifier to drive "named speaker".
Then you will get some help in preparing a specification.
At the moment you appear to know nothing about ClassA.
Go and do a lot of reading.
Your brief may become.
I can't afford a ClassA amplifier, I have now decided I want a good audio quality amplifier.
Hi Andrew these are the drivers that will be used as 2 way speaker with one midwoofer and one tweeter
TW030WA05 to 08 or TW030WA01
WF120BD03_04
Subwoofer as 1 x 12 inch Peerless sls
Madisound Speaker Store
I want to use the amp in 4 ohm mode considering 50watts into 4 ohms.
Its 6 channel amp only the subwoofer channel can be on Class AB to get more power.
Can you please tell me what has to be chosen.
TW030WA05 to 08 or TW030WA01
WF120BD03_04
Subwoofer as 1 x 12 inch Peerless sls
Madisound Speaker Store
I want to use the amp in 4 ohm mode considering 50watts into 4 ohms.
Its 6 channel amp only the subwoofer channel can be on Class AB to get more power.
Can you please tell me what has to be chosen.
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