2SK223: not any datasheet found. Any equivalent?

[Tormy]

These JFETs are used in microphones as AKG and so on. I don't find any datasheet about it as well as any equivalent.
Any one can help please?

EDIT: few minutes ago I got the datasheet of the 2SK223. I attach it here. But still my question: what is a suitable equivalent for it?

 

[Khron]

Did you get that part number from a schematic, or..?

 

[Tormy]

Did you get that part number from a schematic, or..?

Yes right from the schematic

 

[Tormy]

Please here the screenshot
UPDATE: I was able to get the datasheet of the 2SK223 few minutes ago as well (I will update my post, if possible).
But still the question: what's a suitable equivalent?

 

[Khron]

Well, i'm no math expert, but "223" is nowhere near the same as "233"...

I know it might sound a bit obvious / redundant, but you usually have better chances finding what you're looking for, by searching for what you ARE looking for, rather than what you're NOT looking for...

 

[Tormy]

Well, i'm no math expert, but "223" is nowhere near the same as "233"...

I know it might sound a bit obvious / redundant, but you usually have better chances finding what you're looking for, by searching for what you ARE looking for, rather than what you're NOT looking for...

I'm sorry. Me bad. It's 223. I corrected the topic.

 

[granger.frederic]

https://www.ebay.fr/itm/143107435798?hash=item2151de2d16:g:3YkAAOSw8iZcTzJQ
regards
Fred

 

[Tormy]

https://www.ebay.fr/itm/143107435798?hash=item2151de2d16:g:3YkAAOSw8iZcTzJQ
regards
Fred

Hello Fred

no please I can't consider any eBay stuff. Too many times I got fake components. That's why I asked if ever an equivalent is made.

 

[granger.frederic]

The seller is OK but... you can use any low noise n-Jfet with approaching data, however the pinout and biasing need attention...
the circuit is "fetron" type, trying to emulate tube...

 

[Tormy]

The seller is OK but... you can use any low noise n-Jfet with approaching data, however the pinout and biasing need attention...
the circuit is "fetron" type, trying to emulate tube...

Yes it's a kind of cascode (sorry: it is a cascode) with constant current generator. I have found all the JFETs (equivalents) but this one. The problem is to find oen with identical (or very closed) parameters, especially for the noise figure, since the C-input is mitigated by the Cascode configuration

EDIT: Note, it's not indicated on the schematics whether or not the 2 JFETS (T101 and T102) are the same type. I'm guessing: yes they are.

 

[cyrano]

Have you checked this page?

https://transistordata.com/mosfet/2sk223/equivalent
It lists equivalents:

2SK0601
2SK0615
2SK066400L
2SK0664G0L
2SK066500L
2SK0665G0L
2SK1000
2SK1001
2SK1004
2SK1005

 

[Tormy]

Have you checked this page?

https://transistordata.com/mosfet/2sk223/equivalent
It lists equivalents:

2SK0601
2SK0615
2SK066400L
2SK0664G0L
2SK066500L
2SK0665G0L
2SK1000
2SK1001
2SK1004
2SK1005

No I didn't get that page. I'm checking oen by one because some of them are not equivalent, some others are discontinued, however I'm still checking them to compare with the 223. Thank you.

 

[Voyager10]

There's an AKG C414B-TL service manual here:
AKG

It lists a J305 for T101 and 2SK772E for T102. A quick Google says Mouser have an (InterFET) J305 and Farnell have a 2SK772E from Onsemi.

 

[RoadrunnerOZ]

I’d suggest looking at the actual transistors on the board and getting the part numbers from those - there seems to be a conflict in what is used for T101 and 102 between the schematic you posted and an AKG schematic parts list posted by Voyager10 for the same mic. There were different versions of boards for these so best you check actual and not rely on schematic for parts ID. The 2SK223 is readily available here and in stock. AU$1.80. Not sure what country you are in…..
https://www.wagneronline.com.au/2sk/semiconductors/electronic-components/2sk223-22337/959285/pd/

 

[Tormy]

Thank you guys. Yes I d notice this discrepancy on the service manual (I have it here).

I'm wondering why 2 different JFETs in a cascode since normally it's used the same type, so I was a bit disoriented.
I also checked the J305 datasheet to spot similarities with the 223 but it's far to be identical. From the datasheet of the 223 I posted here, I notice it's way different.

The noise figure of both is not the lowest ( is expressed in dB and not in nV/√Hz but in the J305 datasheet there is ALSO the noise density which is 4nV/√Hz ... not any idea of the 223 ), but the Ciss of the J305 is much lower than the 223. Voltage Supply is different. Idss (mA) on the 223 is 1.2 to 24 while J305 = 1 to 8 ... it looked like "take any JFET you like and put it on the circuit" but I'm sure t's not exactly in this way

 

[RoadrunnerOZ]

If you notice it says “selected” for the J305 - this means that maybe 1 in 100 or 1000 of these is the right value for the location - but then we don’t know what the criteria are for the selection process.
First though you need to determine what’s on your mic preamp board.
Are they 2 x 2SK223 OR a J305 and a 2SK772-E?
Are the transistors blown?

 

[Tormy]

If you notice it says “selected” for the J305 - this means that maybe 1 in 100 or 1000 of these is the right value for the location - but then we don’t know what the criteria are for the selection process.
First though you need to determine what’s on your mic preamp board.
Are they 2 x 2SK223 OR a J305 and a 2SK772-E?
Are the transistors blown?

Checked out now. On the mic there are 223s. One of them is not conducting at all. i mean taking it out, short circuiting G and S, and supplying the Drain with just a 9V battery, I have no current. Not clue on any cause could destroy it (it's not belonging to me)

 

[RoadrunnerOZ]

It seems you should just replace them both. They seem to be readily available without resorting to equivalent replacements.
There is a note on the schematic from recordinghacks.com that your paste is an excerpt from, that T101 is selected type - what that exactly means in this case I’m not sure but I’d imagine that T101 & 102 should be very closely matched.
If the mic is not yours what are you doing with it? Buying it or trying to fix it?

 

[Tormy]

It seems you should just replace them both. They seem to be readily available without resorting to equivalent replacements.
There is a note on the schematic from recordinghacks.com that your paste is an excerpt from, that T101 is selected type - what that exactly means in this case I’m not sure but I’d imagine that T101 & 102 should be very closely matched.
If the mic is not yours what are you doing with it? Buying it or trying to fix it?

I'm just trying to fix it.

 

[RoadrunnerOZ]

Are you able to source the transistors where you are?