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Old 8th October 2009, 12:26 PM   #1
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Default B1 Buffer Preamp - FET choice?

B1 Buffer Preamp - FET choice?
I am trying to build my own B1 Buffer Preamp and need to match the FET.
Is there anyone ever tried the K389 which is the dual type FET and no need to match the FET.

I mean the LSK389 from Linear Systems.Thanks.
http://www.linearsystems.com/datasheets/LSK389.pdf
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Old 8th October 2009, 12:33 PM   #2
Atilla is offline Atilla  Norway
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I don't see why it wouldn't work perfectly with the B or C types.

What price can you find those for?
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Old 8th October 2009, 12:36 PM   #3
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Quote:
Originally Posted by Atilla View Post
I don't see why it wouldn't work perfectly with the B or C types.
What price can you find those for?
Price?
not sure now.
But if choosing LSK170,I will buy 1000PCS or more to do some experiments.
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Old 8th October 2009, 12:39 PM   #4
AndrewT is offline AndrewT  Scotland
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Hi,
the LSK389b will work well in a B1.

The 389 is a pair of thermally coupled k170 in a single seven legged package. The tolerance in the spec is 0.9:1 i.e. a spread of <=11%. In practice they are likely to be much closer and good enough for a B1.
You will need to measure the Idss of both halves to find which is the higher Idss device in the package and then decide which of these is adopted as the upper device and which the CCS.

How much to a buy a pair of LSK389b?

A 1000 LSK389 will cost >$2000
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Last edited by AndrewT; 8th October 2009 at 12:43 PM.
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Old 8th October 2009, 12:49 PM   #5
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Quote:
Originally Posted by AndrewT View Post
Hi,
the LSK389b will work well in a B1.

The 389 is a pair of thermally coupled k170 in a single seven legged package. The tolerance in the spec is 0.9:1 i.e. a spread of <=11%. In practice they are likely to be much closer and good enough for a B1.
You will need to measure the Idss of both halves to find which is the higher Idss device in the package and then decide which of these is adopted as the upper device and which the CCS.

How much to a buy a pair of LSK389b?

A 1000 LSK389 will cost >$2000
Great!I am waiting of the quotation of LSK389B,but this means that I need to layout the PCB by myself.
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Old 8th October 2009, 12:53 PM   #6
Atilla is offline Atilla  Norway
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At least the B1 is fairly easy to do. You could even go p2p without problems or too much of a mess.
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Old 9th October 2009, 11:36 AM   #7
early is offline early  United Kingdom
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If it helps any I've used a couple of different fet's in mine .

J310's which sounded very punchy , they also worked very nicely off a 12v battery .

2SK369's which I've settled on , not quite as dynamic as the J310's but much more refined sounding , they are far more neutral than the 310's which are probably injecting a bit of their own character .
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Old 21st August 2010, 07:09 PM   #8
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Default But LSK389B in TO-71 package...

I would be interested in buying 10 to 25 pcs of LSK389B in the TO-71 can package if there are any group buys being made.
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