Hi,
I have another question because my first poweramp I had used vertical mosfets irf540 and 9540 and it was not very stable on capacitive load. I would like to know if it is a disadvantage of vertical mosfets? Thank You! Maxpou
I have another question because my first poweramp I had used vertical mosfets irf540 and 9540 and it was not very stable on capacitive load. I would like to know if it is a disadvantage of vertical mosfets? Thank You! Maxpou
Hi Max,
we are waiting for you to do more research.
540/9540 should work just fine when the design is chosen to suit them.
Choose the wrong design or a poor PCB and any transistor can fail.
Single FETs can operate without source resistors.
Multiple pairs need accurate balancing. The source resistors help this process. Try for 50mV to 150mV across each source resistor at quiescent current and about 2V to 3V at maximum output
we are waiting for you to do more research.
540/9540 should work just fine when the design is chosen to suit them.
Choose the wrong design or a poor PCB and any transistor can fail.
Single FETs can operate without source resistors.
Multiple pairs need accurate balancing. The source resistors help this process. Try for 50mV to 150mV across each source resistor at quiescent current and about 2V to 3V at maximum output
maxpou said:
No I don't think so. I use Verticals, and have not encountered
issues with load instability, but then I use simple circuits with
minimal feedback. As you increase the complexity and feedback
you have to more carefully examine your stability issues and
compensate the amplifier accordingly.
😎
Hi,
i'm really unhappy because i don't have source resistance 0.22 but 0.1 and i would like to know if it's OK when i will make turn-on of my amp it don't burn. thank you! Maxime
i'm really unhappy because i don't have source resistance 0.22 but 0.1 and i would like to know if it's OK when i will make turn-on of my amp it don't burn. thank you! Maxime
0R1 is too low a value, but the amp won't burn.
The Buzquito schematic if for lateral FETs and there is not enough bias voltage to make IRF types conduct.
When you get enough voltage to make the IRF types conduct, you will need to run it in class A unless you thermal compensate the bias for class AB.
The Buzquito schematic if for lateral FETs and there is not enough bias voltage to make IRF types conduct.
When you get enough voltage to make the IRF types conduct, you will need to run it in class A unless you thermal compensate the bias for class AB.
Hi DJK,
i made test with 1 pair of vertical mosfet, but i placed trimpot 10K between gates, it's ok but i'm afraid when i will try with 3 pairs of mosfets. Thank You! Maxpou
i made test with 1 pair of vertical mosfet, but i placed trimpot 10K between gates, it's ok but i'm afraid when i will try with 3 pairs of mosfets. Thank You! Maxpou
Hi everybody,
somebody can explain to me why this schem of buzquito could not function with vertical mosfets. there something which i don't understand... Thank You! Maxime
somebody can explain to me why this schem of buzquito could not function with vertical mosfets. there something which i don't understand... Thank You! Maxime
Hi Maxime,
First of all, you should understand the difference between Lateral and Vertical mosfets. Try to do some search in this forum. You can start with this :http://www.diyaudio.com/forums/showthread.php?s=&threadid=88662&highlight=
Regards
Spiros
First of all, you should understand the difference between Lateral and Vertical mosfets. Try to do some search in this forum. You can start with this :http://www.diyaudio.com/forums/showthread.php?s=&threadid=88662&highlight=
Regards
Spiros
Hi Max,
lat FETs can operate without a temperature compensator on the voltage bias feeding the output stage.
VertFets must have a temperature compensator on thevoltage bias feeding the output stage.
You cannot swap vert FETs into a design for lat FETs. The FETs will suffer thermal runaway and could/maybe will suffer catastrophic thermal/current overload.
Go and do some reading instead of asking the same questions hoping someone will give you the answers you want to hear.
lat FETs can operate without a temperature compensator on the voltage bias feeding the output stage.
VertFets must have a temperature compensator on thevoltage bias feeding the output stage.
You cannot swap vert FETs into a design for lat FETs. The FETs will suffer thermal runaway and could/maybe will suffer catastrophic thermal/current overload.
Go and do some reading instead of asking the same questions hoping someone will give you the answers you want to hear.
Hi AndrewT,
i wrote to me in post 11: this circuit ONLY works with lateral FETs and i only asked WHY! Because with my first i used IRF mosfet and i don't have a problem. I set the bias very slow, I leave him time to heat and i drop the bias for have the bias that i wish. Then i don't asked the question hoping someone will give me to answer i want to hear but i try to understand. Maxpou😀
i wrote to me in post 11: this circuit ONLY works with lateral FETs and i only asked WHY! Because with my first i used IRF mosfet and i don't have a problem. I set the bias very slow, I leave him time to heat and i drop the bias for have the bias that i wish. Then i don't asked the question hoping someone will give me to answer i want to hear but i try to understand. Maxpou😀
and you're in various threads trying to get someone to agree that one can substitute vert FETs for Laterals in a circuit designed for Laterals.
Hi AndrewT,
i tried this scheme with 3 pairs of vert mosfet last night and it function. When i turn on the poweramp the bias is 15mA, after 3 hours to heat it have 150mA bias per device and it's stable. Of course if the ambient temperature change the bias change too but it have a good leeway. Thank you! Maxpou🙂
i tried this scheme with 3 pairs of vert mosfet last night and it function. When i turn on the poweramp the bias is 15mA, after 3 hours to heat it have 150mA bias per device and it's stable. Of course if the ambient temperature change the bias change too but it have a good leeway. Thank you! Maxpou🙂
- Status
- Not open for further replies.