Previously in post #195 & #196, we published Id vs Vgs curves for the IRF and FQP output devices.
There have been some discussions about comparing 2SK2013 / 2SJ313 vs FQP3N30 / FQP3P20 in this or other applications.
I thought it would be best to compare their Vgs vs Id directly.
The first is Vgs vs Id.
Red is Fairchild FQP3N30 and blue is Toshiba 2SK2013.
The Fairchild has a higher Vgs over the entire range of Id (to 300mA).
The 2nd is vgs vs Id around the bias point, so that the static bias voltage has been subtracted.
One can see that the Fairchild also has a higher transconductance.
The rest, such as capacitances, etc. are best referred to corresponding datasheets.
Patrick
:
There have been some discussions about comparing 2SK2013 / 2SJ313 vs FQP3N30 / FQP3P20 in this or other applications.
I thought it would be best to compare their Vgs vs Id directly.
The first is Vgs vs Id.
Red is Fairchild FQP3N30 and blue is Toshiba 2SK2013.
The Fairchild has a higher Vgs over the entire range of Id (to 300mA).
The 2nd is vgs vs Id around the bias point, so that the static bias voltage has been subtracted.
One can see that the Fairchild also has a higher transconductance.
The rest, such as capacitances, etc. are best referred to corresponding datasheets.
Patrick
:
Attachments
We build our own.
The stuff you can buy for reasonable money is not accurate enough for us (better than 0.1%).
See :
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1520.html#post4795279
Post #15191
Patrick
The stuff you can buy for reasonable money is not accurate enough for us (better than 0.1%).
See :
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1520.html#post4795279
Post #15191
Patrick
Simply stunning Oliver
easily among the most beatifull builds i have seen in this site ...or any other for that matter.
Tiroler is my ref here !
😀
Guys, which is better, SE Mosfet or F5 headamp ? Which is clearer for vocals ? I'll use this for both watching movies and listening to music.
Built my F5HA on vero board. Schematic included.
Power supply is +/-16V from diy Kubota regulator. mosfet drain resistor are two 6.8R parallel because I can't get 3.3R 1W from local shop lol.
I used K246 J103 with matched Idss of 3.21 for 1 channel and 3.27 for the other.
I have a question, is R_drain of jfet set right?
Power supply is +/-16V from diy Kubota regulator. mosfet drain resistor are two 6.8R parallel because I can't get 3.3R 1W from local shop lol.
I used K246 J103 with matched Idss of 3.21 for 1 channel and 3.27 for the other.
I have a question, is R_drain of jfet set right?
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Last edited:
Your JFETs have very low Idss.
You need to change the drain resistors to give you something like 4V across them.
Also depends on the Vgs of your MOSFETs
I assume you are using IRF.
Patrick
You need to change the drain resistors to give you something like 4V across them.
Also depends on the Vgs of your MOSFETs
I assume you are using IRF.
Patrick
Incorrect.
In the circuit your drew, the JFETs have 200R source resistors.
So the actual bias is much lower than Idss.
Likely to be around 1.5~2mA.
Patrick
In the circuit your drew, the JFETs have 200R source resistors.
So the actual bias is much lower than Idss.
Likely to be around 1.5~2mA.
Patrick