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-   -   2N series Fets like 2SK246/ 2SJ103 ? (http://www.diyaudio.com/forums/solid-state/80546-2n-series-fets-like-2sk246-2sj103.html)

ashok 30th May 2006 10:34 AM

2N series Fets like 2SK246/ 2SJ103 ?
 
Since I cannot find Spice data for 2SK246 and 2SJ103 , I assume if there are 'similar' small signal FET's like these in the 2N range or some other series , their Spice models will be more easily available. They must be complementary devices.
Thanks.
Cheers.

Netlist 30th May 2006 11:18 AM

You've got mail. :)

/Hugo

ashok 30th May 2006 11:23 AM

Thanks Hugo .
Ashok.

padamiecki 1st June 2006 10:03 AM

Quote:

Originally posted by Netlist
You've got mail. :)

/Hugo


Hugo,
may I ask one too?
Thank you in advance!

davygrvy 16th July 2007 11:58 PM

Could I get a copy of the SPICE models for the 2SK246BL and 2SJ103BL, too?

juma 2nd June 2008 10:33 PM

Can you please send me spice models for 2SK246 and 2SJ103 ?
Thanks a lot ! :)

Cauhtemoc 3rd June 2008 06:53 AM

From the Orcad libraries:

Quote:

.model J2sk246 NJF(Beta=1.07m Rs=56.76 Rd=56.76 Betatce=-.5 Lambda=2.8m
+ Vto=-2.638 Vtotc=-2.5m Cgd=10.38p M=.4373 Pb=.3905 Fc=.5
+ Cgs=6.043p Isr=112.8p Nr=2 Is=11.28p N=1 Xti=3 Alpha=10u Vk=100
+ Kf=1E-18 Af=1)
Quote:

.model J2sj103 PJF(Beta=2.197m Rs=76.76 Rd=76.76 Betatce=-.5 Lambda=735.3u
+ Vto=-2.037 Vtotc=-2.5m Cgd=18.95p M=.5045 Pb=.3905 Fc=.5
+ Cgs=17.02p Isr=38.48f Nr=2 Is=3.848f N=1 Xti=3 Alpha=10u Vk=100
+ Kf=1E-18 Af=1)

linuxguru 3rd June 2008 07:36 AM

Just out of curiousity - apart from the Vds rating of 50V, in what way is the 2sk246 superior to say, the BF245c or similar?

lineup 3rd June 2008 10:06 AM

Quote:

Originally posted by linuxguru
Just out of curiousity - apart from the Vds rating of 50V,
in what way is the 2sk246 superior to say, the BF245c or similar?

I would not say 2SK246 or any JFET is superior, to another.
It all comes down to what specific job you want your JFET to do.


And this is what makes a good audio amplifier designer:

1. Knowledge about different components.
This is one of the most fundamental thing.
How they behave in different circuits and
what good features and limitations any component has.

We see often Nelson Pass and other world class amplifier designers
use the same transistors over and over again.
This is not necessarily because they are the best HEXFET.
But Nelson Pass knows these ( IRF240, IRF9240, IRF610, IRF9610 )
like his own backpocket.
This is why he can get them perform 99.9% time after time.

When he wants to use some hypermodern, like LU1010 power JFET,
he needs to spend time experimenting, testing, to get knowledge and be familiar with the new ones.
If not, he will not be able to get more than 70-80% out of these,
however much better they are, than older devices.

2. The ability to set up good working environment in circuit.
With currents, voltages, that suits the components chosen as optimal as possible.

And arrange them all, so they work 'perfectly' together.

------------------------------------------


Speaking of 3 common JFETs.
Quote:

BF245 - 30 Volt
JFET VHF/UHF Amplifiers
http://www.onsemi.com/pub_link/Collateral/BF245A-D.PDF

2SK246 - 50 Volt
For Constant Current, Impedance
Converter and DC-AC High Input
Impedance Amplifier Circuit Applications
http://www.ampslab.com/PDF/2sk246.pdf

2SK170 - 40 Volt
Low Noise Audio Amplifier Applications

Recommended for first stages of EQ and M.C. head amplifiers.
http://www.semicon.toshiba.co.jp/doc...eet_071101.pdf
The limiting factor for JFET is often Max Voltage and sometimes Max Current ( IDSS ).
Aside from BF245 is 'only' 30 Volt, you see it is mainly for VHF/UHF use.
RADIO frequencies, while audio is AF, LF. Lower frequency.
Nevertheless, BF245 can be used for current sources in audio amplifiers.
To serve the other transistors. BF245 is not a bad transistor.

2SK246 has an attractive feature ( like the PFET 2SJ103 ).
It can take 10 Volt higher, than 2SK170.

Finally, 2SK170.
2SK170 - 40 Volt
Low Noise Audio Amplifier Applications
Recommended for first stages of EQ and M.C. head amplifiers.


... there is no need to comment on that, is there ;)
It is no coincidence 2Sk170 is very popular in Audio Amplifiers.
Fairly high voltage, 40 V, but most of all low noise and
it is recommended by Toshiba for demanding audio amplifiers.
MC Phono RIAA, for example.


Regards - lineup


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