A real Vendetta?

[Algar_emi]

So to resume possible replacement transistors are:

J175 from Comet.bg
J112 unknown
2SK147, replace with two 2SK389
2SK240, replace with 2SK389
2SJ75, replace witn 2SJ109
J203, now smd part sst203
2SJ72, replace with 2SJ74
2SJ76 and 2SK213 still manufacture by Renesas...

Possible replacement for the 2SJ76/2SK213 that seem impossible to get either may be the IRFZ24N (N-channel) and IRF9Z34N (P-channel) power MOSFETs from International Rectifier. These are 5th-generation HEXFET™ devices for linear use and are available from Digi-Key and Newark Electronics. What do think of these replacement?


Any suggestion for J112?

Thanks....

[Algar_emi]

Well, just found that the J112 and J175 are available from Mouser

Thanks Peter for the tip.

And that the J203 is now available in SOT-23 package under the code:

MMBFJ203: Fairchild Semiconductor Small Signal Transistors J203

From Mouser as well

[jacco vermeulen]

Originally posted by Algar_emi
MMBFJ203

Don't wait up.

[john curl]

It would appear that it will be virtually impossible for anyone but Erno Borbely or me to build an accurate Vendetta preamp. I agree that MOST of the parts are not made anymore. Some can be substituted for directly, but others are almost impossible to duplicate. I don't know why, but jfets are becoming almost impossible to purchase at any price. However, IF you are willing to pay the price for the parts, then you can get very high performance. Many criticisms have been made of Erno's prices, but they are actually reasonable, considering that the parts are not available anywhere else.

[Algar_emi]

Do you mean that the MMBFJ203 is not the J203? or that it can be bought? If not what would be the replacement for this one?

Here a first draft of the Supply PCB

[kamis]

Toshiba 2SK30A-GR is a good TO-92 replacement for J-203 in CCS. It is a very good but neglected N J-fet.
It is not recommended to replace Hitachi J79/K216 with IRF vertical MOSFET -s.I tried it,.taking in account larger vgs, but always got worse sonic results. It is a controversial matter and subject of endless discussion in this forum.

[jacco vermeulen]

Originally posted by Algar_emi
or that it can be bought?

I've yet to see them readily available and/or in low volume, been checking the SMDs for some time. The Tosh 2SK30A is like a quarter for 10-up at the Georgia audiolab.

(did you manage to get the crystal display, Sylvain ?)

[MRupp]

Many criticisms have been made of Erno's prices, but they are actually reasonable, considering that the parts are not available anywhere else.

I find his prices acceptable, especially considering that he is pretty generous in sharing his knowledge and intellectual property, so there is good reason to support him. I presume his business is pretty small and does not make him filthy rich.

I agree that MOST of the parts are not made anymore. Some can be substituted for directly, but others are almost impossible to duplicate.

My uneducated guesses would be:

2SK240/2SJ75 can easily be substituted with 2SK389/2SJ109, the latter may even be better due to being monolithic. The little data that I have suggest marginally lower noise for the SK240 but these are average values anyway and may depend on what production batch your specimen come from.

The 2SK147 and complementary are more tricky. Their equivalent noise resistance is ca. 34 Ohms compared to 55 Ohms for the 2SK170 (Borbely: All JFET MM/MC Preamp, part I), and the 2SK147 has somewhat higher transconductance at the same current. So you cannot directly substitute them and expect the same results. One obvious solution could be using 4 pairs of the 2SK170/SJ74 for the common source input stage and cascode them with 2 pairs of 2SK170/SJ74.

Purely from a noise perspective this should be just as good, but there could be other factors influencing the sound and that I am unaware off?

[Algar_emi]

I got an offer from a store that said that the direct replacement for these FET are:

2SJ76 -> 2SJ79
and
2SK213 -> 2SK216

Will they works into the Vendetta?

[john curl]

Yes, they should work.