Just wondering, Surely there are other devices, but most of the Pass Items require these two J-fets. Obviously, they are slowly going away. Most of the Pass projects require them.
Once gone, what will be the standard replacement, or other complemetary pairs the will accomplish the same goal? I recall one company has a 2SK170BL replacement, but no 2SJ74BL replacement.
Just wondering,
Russellc
Once gone, what will be the standard replacement, or other complemetary pairs the will accomplish the same goal? I recall one company has a 2SK170BL replacement, but no 2SJ74BL replacement.
Just wondering,
Russellc
Yes Nelson there must be somewhere genuine parts but in past weeks i bought 2sj74BL from schuro, utsource and NIKKO and they all measure between 17ma and 20ma Idss......
i would like to buy genuine ones...but where ?
PS: i did test my setup with other genuine ones i have , that i had previously tested and these confirmed the values.
i would like to buy genuine ones...but where ?
PS: i did test my setup with other genuine ones i have , that i had previously tested and these confirmed the values.
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Yes Nelson there must be somewhere genuine parts but in past weeks i bought 2sj74BL from schuro, utsource and NIKKO and they all measure between 17ma and 20ma Idss......
i would like to buy genuine ones...but where ?
PS: i did test my setup with other genuine ones i have , that i had previously tested and these confirmed the values.
Test them for transconductance. 2SJ74BL's shouldn't have Idss anywhere near that high.
You can use the GR rated devices.
Would you kindly provide more specific answer? I am afraid we have been 'hoping' about 3 years or more for them to produce the LSJ74.
Regards,
They would be most certainly fakes, I am afraid. I bought parts labeled as '2SJ74' from one HK supplier, as a trial. They also measured some 17 - 20 mA Idss. But have low transconductance AND noise higher about 20 - 30dB at low frequencies. I test the parts in my discrete preamps and noise spectrum + FFT distortion measurement are the best answer if the part is fake or not.
Regards,
I just measured my quadruples of SK170 and SJ74 I got from Spencer
http://www.diyaudio.com/forums/swap-meet/131284-toshiba-2sk170bl-sales-56.html
Exactly 10,2 mA for all! Good work, Spencer! Keep on selling the real stuff!
http://www.diyaudio.com/forums/swap-meet/131284-toshiba-2sk170bl-sales-56.html
Exactly 10,2 mA for all! Good work, Spencer! Keep on selling the real stuff!
I also have quadruples from Spencer...genuine stuff, all measure as you say.
The 2SK170BL are not a problem it seems, i have plenty, all tested and matched.
It's the 2SJ74BL that are much more scarce that are the problem.
He delivers J74 too....
When I meant quadruples I meant two SK and two SJ, ideal for UGS!
Thanks for your image, masag1. The 2SJ74BLs bearing the code "7C" have already been described as fakes by @h_a here:
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1033.html#post2476459
Now you can guess that these "High Idss 2SJ74BL" offered here
20 X 2SJ74BL (10 Matched pairs) - HIGH IDSS | eBay
are also fakes (Seller says: They were manufactured in Malaysia)
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@CeeVee and PMA:
What's the batch code of your fake 2SJ74s?
Thanks for the information!
Hi,
Selectronic dealer of france have all the time this parts in stock BL or GR kinds. You must just matched them.
This dealer have also other specific parts for audio : nichicon, elna, black gates capa ....
www.selectronic.fr
Selectronic dealer of france have all the time this parts in stock BL or GR kinds. You must just matched them.
This dealer have also other specific parts for audio : nichicon, elna, black gates capa ....
www.selectronic.fr
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