Hi Grey!
Nice that you give here some advice as well!
Well, I thought of replacing the 2SK147 with the recent K369, just to find out that there is no complementary part? Is that so, or am I just missing something?
Well, otherwise one would have to substitute the 2x 2SK147 in the frontend for 4x 2SK170 to get the same transconductance.
All the best, Hannes
Nice that you give here some advice as well!
Well, I thought of replacing the 2SK147 with the recent K369, just to find out that there is no complementary part? Is that so, or am I just missing something?
Well, otherwise one would have to substitute the 2x 2SK147 in the frontend for 4x 2SK170 to get the same transconductance.
All the best, Hannes
LP-s are still respectable,and some are the highest quality source material.
IRF MOSFETS are widely available components in my country . Hitachi sold fet producing division to Renesas,which produces lateral MOSFET-s
only. Toshiba devices I would call "semi-lateral"- their Vgs is much smaller than IRF fets. Both brands are subject of faking . I use genuine Renesas laterals in my phono preamp, same type as used in Vendetta second stage.
Vendetta MC stage J-fets are obsolete but still available at some deleted components distributors at astronomic prices. Well known K170/J74 is an alternative , but s/n ratio will be 6 db worse with 0.2mv cartridge nominal output and 3ohm dc resistence. With 0.3mv and 6 ohms difference is only 2.5 db
Second stage input dual J-fets could be replaced with K389/J109probably the most wanted audiophile semiconductors.
Output MOSFETS are Renesas laterals, still in production.
Vendetta phono preamp uses well known RIAA eq. topology: low noise gain block-passive HF eq.-active feedback bass boost second stage.Erno Borbely uses same approach in his designs.MM cartridge owners (I use both types) could build second stage ,and for input stage some of Borbely's old or new circuits. I am going to incorporate Vendetta power supply in my MC/MM phono stage which is combination of old Borbely's modules.Vendetta is built on double sided gold plated pcb but it is not so important. It is impossible to make perfect soldered joints on any gold plate surface ,even with special alloys.
J-175 at Comet Electronic ,Belgrade
J-112 MG or SD el. Nis
J
2sk369 is the lowest noise J-fet currently available but without complementary eq.It is very useful in no feedback paralleled J-fets MC preamps.
Thanks you for your input!
Forgive me, but that I don't understand.
As far as I know, you need 2x K170 (22mS) to get the same transconductance of 1x K147 (40mS).
Paralleling devices does not increase but decrease noise, as it is added geometrically.
So to my knowledge 2xK170 fully replace (also in terms of input capacitance) the K147.
Please correct me, if I'm wrong. Have fun! Hannes
Forgive me, but that I don't understand.
As far as I know, you need 2x K170 (22mS) to get the same transconductance of 1x K147 (40mS).
Paralleling devices does not increase but decrease noise, as it is added geometrically.
So to my knowledge 2xK170 fully replace (also in terms of input capacitance) the K147.
Please correct me, if I'm wrong. Have fun! Hannes
Oh and I forgot:
Grey, it's big news to hear that you have a phono stage on your backburner! It's just a pity that you are a mortal that needs to earn money for a living instead of having the time to feed us trolls with clever schematics ;-))
Can't wait to see a schematic from your phono stage!
All the best, Hannes
Grey, it's big news to hear that you have a phono stage on your backburner! It's just a pity that you are a mortal that needs to earn money for a living instead of having the time to feed us trolls with clever schematics ;-))
Can't wait to see a schematic from your phono stage!
All the best, Hannes
Look at noise figures in datasheets.K147/j72 have 34 ohms equivalent noise resistance and generating the same amount of noise as a 34ohm resistor. K170/J74 eq. noise resistance is 55ohm so paralleled can be calculated to 25.5 ohm.
So, we can see that two lower transconductance paralleled J-fets are slightly better than one high tr. device. Drain current is 5ma.
Vendetta, like Borbely's phono, is a single ended complementary topology and has 3db lower noise than differential circuitry. Ohmic resistance of cartridge generate noise just as active components.
Nalaze se negde kod Sava Centra. Nisam sacuvao racun.
2SK369
I think the 2SK369 is fundamentally the same as two 2SK170 in parallel, twice the current capability but also twice the capacitance. It shouldn't be a problem using the 2SK170 instead.
I think the 2SK369 is fundamentally the same as two 2SK170 in parallel, twice the current capability but also twice the capacitance. It shouldn't be a problem using the 2SK170 instead.
What would be the possible replacement for the J103?
Is the 2SJ103 an equivalent?
What type of SK170 and SJ74 to get BR, BL or V?
Is the 2SJ103 an equivalent?
What type of SK170 and SJ74 to get BR, BL or V?
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....
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....
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
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
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.
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.
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.
Algar_emi said:
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 ?)
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.
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?
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?
2SJ76 -> 2SJ79
and
2SK213 -> 2SK216
Will they works into the Vendetta?