Acceptable Idss Range for 2SK270-BL and 2SJ74-BL

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Doppler9000

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Joined 2010
Nelson Pass said:
Idss of 6 mA will work on these amplifiers, sometimes with small adjustment.

8 mA is a more desirable, and is the presumed default most of the time.
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Excellent- thanks so much, Nelson.

I have ordered some (Toshibas) from an online seller and requested sets close to 8mA Idss (he tests at 9.00 V).

Seems a legit supplier - it is a (pro) audio manufacturer who bought the JFETs from "top-line U.S. distributors". Fingers crossed.

John
 
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Doppler9000

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Joined 2010
Russellc said:
Who did you get them from? The only dependable source with idss all through the sweet area I know of is Spencer. Always genuine.

Russellc
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The seller is Millennia Music & Media Systems.

I got them here (hoping they were a smart buy). I note that the upper end of the Idss range is lower than when I bought. I requested mine were as close as possible to 8 mA. He as pairs as wellas quads, as well as some other FETs.

"FETs are matched in pairs to within 0.03mA Idss AND 4mV Vgs."

Toshiba 2SJ74 + 2SK170 MATCHED QUAD to 0.03mA AND 4mV 7.2mA-7.4mA Idss Range
 
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wdecho

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Joined 2014
I have bought from the guy in the past but I cannot remember if they were genuine or not. During that time, before the LSJ74 was available, I tried a few of the Ebay sellers. Most were fakes. Buyer beware on Ebay. It is always best to have matched sets but not a deal breaker if they are not. You will have more 2nd or more 3rd with a mismatched pair but it can be corrected with some source resistance if you do not like the sound. Sometime people like the sound with a mismatched pair better depending on whether you like more or less 2nd harmonic.

My vote is for LSK only for the J-fets.
 
Nelson Pass

Nelson Pass

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Joined 2001
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Doppler9000 said:
The seller is Millennia Music & Media Systems.

I got them here (hoping they were a smart buy). I note that the upper end of the Idss range is lower than when I bought. I requested mine were as close as possible to 8 mA. He as pairs as wellas quads, as well as some other FETs.

"FETs are matched in pairs to within 0.03mA Idss AND 4mV Vgs."

Toshiba 2SJ74 + 2SK170 MATCHED QUAD to 0.03mA AND 4mV 7.2mA-7.4mA Idss Range
Click to expand...

I know John La Grou personally, I remember when he bought them, and you
can bet he matches them that tightly.
 
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Russellc

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Joined 2003
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Doppler9000 said:
Read above post - I feel good about my analysis and decision.
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Yes, it sounds as you have found a good source. These sources are rare as hens teeth. I have, and I suggest you as well, lay in a small supply to use in the amps you plan to build.

Its nice the store provides the linear versions, but I have previously inquired if idss can be requested, but never got a response. I have a couple sets of them, but have no idea where they measure idss wise.

Havent had a need to find out by measuring them, I just ordered sets measured by Spencer.

Happy amp building!

Russellc
 
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Russellc

Member
Joined 2003
Paid Member
Doppler9000 said:
The seller is Millennia Music & Media Systems.

I got them here (hoping they were a smart buy). I note that the upper end of the Idss range is lower than when I bought. I requested mine were as close as possible to 8 mA. He as pairs as wellas quads, as well as some other FETs.

"FETs are matched in pairs to within 0.03mA Idss AND 4mV Vgs."

Toshiba 2SJ74 + 2SK170 MATCHED QUAD to 0.03mA AND 4mV 7.2mA-7.4mA Idss Range
Click to expand...

Extremely tight matching. Sounds like you chose good units.

Russellc
 
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