Replacement For Toshiba 2SK170/2SJ74

[Nick Sukhov]

The lowest noise P is 2N5452 at just under 3 nV

The lowest noise P is P0099F with 2 nV\sqrtHz [ https://www.interfet.com/jfet-datasheets/jfet-p0099f-geometry-interfet.pdf ]

 

[wayne]

They have a 2 nV process I just don’t see any 2 nV parts with actual part numbers.
They may be able to make some though.

 

[MEPER]

The LSK170 is generally available.
It seems that is the one that comes closest to 2SK170?
https://www.digikey.dk/en/products/filter/transistors/jfets/288?s=N4IgTCBcDaIDIGUDSBGA7ABhAXQL5A
It is a little bit expensive if a lot is necessary to do matching.
Price for 100 pcs is not that bad.......
https://www.digikey.dk/en/pdf/l/lin...170-series-n-channel-jfet-amplifier-datasheet
https://www.eetimes.com/quiet-jfet-features-nearly-zero-popcorn-noise/

 

[Nick Sukhov]

They may be able to make some though.

Yes, and due to almost half the input capacity (18 pF instead of 32 pF of 2SJ74) , I’m thinking about pairing it with the JFE2140 (13 pF instead of 30 of 2SK170).

 

[tiefbassuebertr]

There is now offer this replacement for Toshiba's vintage jFET 2SK170 under ebay item No 185864174433:
https://www.ebay.nl/itm/185864174433
https://www.ebay.com.hk/itm/185864174433
any experiences ?

 

[NicMac]

2SK170 or 2SK177?

 

[JCN]

Looks like 2SK2145.

Regards J-C

 

[tiefbassuebertr]

2SK170 or 2SK177?

2SK170. (wrong naming of images - my mistake)

 

[andynor]

That does not look like 170’s. And, 170s are unlikely to be given an upgrade, just copying their performance is very challenging.

 

[Zen Mod]

it seems someone is taking 2SK2145 as substitute for 2SK170, using case adapter pcb

treating those 2 JFets in one case as one

from 2SK2145 datasheet .......X is type, G is GR current rank, in this case 2.6-6.5mA

doable and effective, but only if taken care of current ranges (GR, BL, V) and appropriate translation between origin and substitute

so, practically translated to BL range of 2SK170, 6.5 to 12mA

 

[exojam]

Is there supposed to be something underneath those two areas that almost look like, I hate to say this, solder blobs (first picture)? I also think this cat could use a little less solder on those pins personally, but that’s just my own opinion and you know what they say about that.

 

[JeffYoung]

No, those are solder jumpers that tie in the second JFET.

 

[exojam]

Thank you.

 

[Tailgunner]

The LSK170 is generally available.
It seems that is the one that comes closest to 2SK170?
https://www.digikey.dk/en/products/filter/transistors/jfets/288?s=N4IgTCBcDaIDIGUDSBGA7ABhAXQL5A
It is a little bit expensive if a lot is necessary to do matching.
Price for 100 pcs is not that bad.......
https://www.digikey.dk/en/pdf/l/lin...170-series-n-channel-jfet-amplifier-datasheet
https://www.eetimes.com/quiet-jfet-features-nearly-zero-popcorn-noise/

What grade (A,B,C,D) of the LSK170 and LSj74 are replacements for the 2SK170-GR and the 2SJ74-GR?

 

[jean-paul]

Hi I just saw the post coming up. I have 6 or 8 2SJ74GR but find it hard to find original 2SK170GR as these keep turning up in new projects while being obsolete for ages. Already got fakes/relabelled 2SK170GR a few times so I decided not to use these. Guaranteed original and made somewhere in the nineties. I can use the money for recent technology devices so if you want these send me a PM with a decent offer.

 

[VIPINSAINI20]

Hello everybody,
I recently find some boxes of Part ID:KSK30YTA D/C1:0241 2002/10/12 Made by Fairchild



I know they are JFets, that's why I bought them as soon as I found them in a local shop, shopkeeper was doing a clearance sale hence they are from 2002
I don't know much about this part and how to make use of them,after doing some quick googling , I found that they can be used to make Audio Circuits,

Problem I'm facing that I don't know how to make proper use of them, how to measur , match them and make sure they work as they should be,

Does anyone have very simple way to match them without any fance equipment setup? Please Give some advise

If anyone of you of have a good Pre-amplifiers(Headphone Amps),10W-20W Class-A with BJTs or Hexfet MOSFets in output stage, any audio circuit which is simple and can make of this jfet ,please share the schematic

 

[jean-paul]

Designing a device with them and publishing the schematic here seems to work pretty well. The more and longer obsolete the higher the demand.

18000 pieces, congratulations wealthy man!

2SK30 is sometimes used as current source in low voltage tube buffers. I happen to also have a lot. Not 18000, Toshiba though

 

[VIPINSAINI20]

@jean-paul , man i'm not a wealthy guy, I just got lucky, I didn't paid much for them, I just got them as cheap as BJTs boxs comes in wholesale.
I have find(with help from a good friend) some schematic but i'm not sure they will work there, because I wants to use BJTs or HEXFETs, but I find schematic with those hard to get laetral fets, like in these below not with Hexfets


Is it possible to use them in these schematics? please let me know

 

[Zen Mod]

inform well how much they're worth

put them on ebay or contact some manufacturer of amplification, or do both, to sell them all

then you'll have enough money to build whatever you want, with any parts of choice