JFETs from Linear Systems - Page 2 - diyAudio
Go Back   Home > Forums > Commercial Sector > The diyAudio Store

The diyAudio Store A forum for discussing anything about the products available in The diyAudio Store.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th October 2013, 04:29 PM   #11
Jason is offline Jason  Australia
:)
diyAudio Administrator
 
Jason's Avatar
 
Join Date: Oct 2000
Location: Melbourne
Blog Entries: 1
Quote:
Originally Posted by RollE2k View Post
Great to hear, but damn those lsj74's were expensive. Especially if you need a few of them matched...
We might offer matched pairs and quads in the future. To be confirmed.

Quote:
Originally Posted by pb1234 View Post
Does anyone know what the odds are of finding a couple matched pairs of LSJ74's if one buys the minimum of 8?

Looks like Grade D is all that's available at the moment. Were the other grades available and just sold out?
Everything sold out very quickly. Currently the best way to find out about new stock is to subscribe to The diyAudio Store stock news and updates thread.

We already have new stock and are packaging it for sale - should be shipping in a week or two.
  Reply With Quote
Old 10th October 2013, 09:32 PM   #12
krath is offline krath  Denmark
diyAudio Member
 
Join Date: Feb 2012
Can someone explain which device grade A,B etc is best for Aleph J power amplifier.
  Reply With Quote
Old 11th October 2013, 05:16 PM   #13
badtoby is offline badtoby  United States
diyAudio Member
 
Join Date: May 2010
Location: Kansas City Mo
Which would be best for a F5?
  Reply With Quote
Old 7th November 2013, 12:03 AM   #14
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
I recently purchased 8 each of LSK170C and LSJ74C from the store and performed measurements of IDSS and Gm at the IDSS current. I share the test results here.

LSK170C
IDSS Gm@Idss
mA mS
_____________
11.60 32.7
11.60 32.8
11.60 32.9
11.62 33.0
11.64 32.9
11.68 32.7
11.68 33.0
11.70 32.9

LSJ74C
IDSS Gm@Idss
mA mS
_____________
11.50 30.5
11.50 28.3
12.40 32.8
14.84 33.9
15.06 33.0
15.76 30.7
17.10 33.1

You can see that the LSK170 parts are nearly identical whereas the LSJ74 parts show a rather large spread of IDSS values. This is probably a reflection of the fab process for the J74 parts still being relatively new. Perhaps there are other factors involved of which I am unaware.
  Reply With Quote
Old 8th November 2013, 12:04 AM   #15
diyAudio Member
 
EDDELARUE's Avatar
 
Join Date: Nov 2004
Location: Brasilia
Send a message via MSN to EDDELARUE Send a message via Skype™ to EDDELARUE
Quote:
Originally Posted by lhquam View Post
I recently purchased 8 each of LSK170C and LSJ74C from the store and performed measurements of IDSS and Gm at the IDSS current. I share the test results here.

LSK170C
IDSS Gm@Idss
mA mS
_____________
11.60 32.7
11.60 32.8
11.60 32.9
11.62 33.0
11.64 32.9
11.68 32.7
11.68 33.0
11.70 32.9

LSJ74C
IDSS Gm@Idss
mA mS
_____________
11.50 30.5
11.50 28.3
12.40 32.8
14.84 33.9
15.06 33.0
15.76 30.7
17.10 33.1

You can see that the LSK170 parts are nearly identical whereas the LSJ74 parts show a rather large spread of IDSS values. This is probably a reflection of the fab process for the J74 parts still being relatively new. Perhaps there are other factors involved of which I am unaware.
For comparison only, what VDS did you use to measure ?
Toshiba 2SK170 Datasheet shows Gm > 40mS for VDS=10V.
__________________
eD
  Reply With Quote
Old 8th November 2013, 12:12 AM   #16
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Quote:
Originally Posted by EDDELARUE View Post
For comparison only, what VDS did you use to measure ?
Toshiba 2SK170 Datasheet shows Gm > 40mS for VDS=10V.
  Reply With Quote
Old 8th November 2013, 03:06 PM   #17
diyAudio Member
 
EDDELARUE's Avatar
 
Join Date: Nov 2004
Location: Brasilia
Send a message via MSN to EDDELARUE Send a message via Skype™ to EDDELARUE
VDS ??
__________________
eD
  Reply With Quote
Old 8th November 2013, 03:26 PM   #18
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Quote:
Originally Posted by EDDELARUE View Post
For comparison only, what VDS did you use to measure ?
Toshiba 2SK170 Datasheet shows Gm > 40mS for VDS=10V.
(Oops, my reply somehow got lost).
I measured Idss with Vds=15. That was the voltage I have used for JFETs for earlier projects.
  Reply With Quote
Old 8th November 2013, 04:30 PM   #19
diyAudio Member
 
EDDELARUE's Avatar
 
Join Date: Nov 2004
Location: Brasilia
Send a message via MSN to EDDELARUE Send a message via Skype™ to EDDELARUE
Quote:
Originally Posted by lhquam View Post
(Oops, my reply somehow got lost).
I measured Idss with Vds=15. That was the voltage I have used for JFETs for earlier projects.


ok!

So, this device has less Gm than k170 at equal conditions. But has no problem.

i wonder if it has a square law on "id vs vgs". i don't think so.
__________________
eD
  Reply With Quote
Old 8th November 2013, 05:08 PM   #20
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Quote:
Originally Posted by EDDELARUE View Post


ok!

So, this device has less Gm than k170 at equal conditions. But has no problem.

i wonder if it has a square law on "id vs vgs". i don't think so.
I measured Id and Gm with three different resistors (0R, 7.5R and 20R) from source to ground, with ground as the DC potential of the gate, and a 20mV, 1kHz sine wave on the gate. I suppose you might be able to infer something about the Id vs Vgs from my data.

Last edited by lhquam; 8th November 2013 at 05:11 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Group Buy: Linear Systems LSK389 / LSK170 JFETs (i.e. Toshiba 2sk389/2sk170 subs) luvdunhill Group Buys 355 11th September 2014 07:55 AM
Hello from Linear Systems Linear Systems Introductions 3 20th March 2006 10:57 PM
P-channel JFETs more linear? lazthegaz Solid State 27 29th June 2004 12:50 PM


New To Site? Need Help?

All times are GMT. The time now is 08:13 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2