B1 Buffer Preamp - FET choice?

androidDIY · 8th October 2009, 12:26 PM

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

Atilla · 8th October 2009, 12:33 PM

I don't see why it wouldn't work perfectly with the B or C types.

What price can you find those for?

androidDIY · 8th October 2009, 12:36 PM

Quote:

Originally Posted by Atilla

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.

AndrewT · 12:43 PM

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

androidDIY · 8th October 2009, 12:49 PM

Quote:

Originally Posted by AndrewT

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.

Atilla · 8th October 2009, 12:53 PM

At least the B1 is fairly easy to do. You could even go p2p without problems or too much of a mess.

early · 9th October 2009, 11:36 AM

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 .

8th October 2009, 12:26 PM	#1
androidDIY diyAudio Member Join Date: Oct 2009 Location: DIY Secret Graden Blog Entries: 9	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

8th October 2009, 12:39 PM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	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 __________________ regards Andrew T. Last edited by AndrewT; 8th October 2009 at 12:43 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Pedja Rogic Buffer and component choice for PCB design	justblair	Chip Amps	143	3rd May 2009 02:54 PM
Buffer choice for IIS Direct	Andypairo	Digital Source	65	31st October 2006 08:56 AM
Again, a preamp tube choice.	redzi	Tubes / Valves	15	19th March 2006 05:12 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

8th October 2009, 12:33 PM	#2
Atilla diyAudio Member Join Date: Jul 2008	I don't see why it wouldn't work perfectly with the B or C types. What price can you find those for?

8th October 2009, 12:53 PM	#6
Atilla diyAudio Member Join Date: Jul 2008	At least the B1 is fairly easy to do. You could even go p2p without problems or too much of a mess.

9th October 2009, 11:36 AM	#7
early diyAudio Member Join Date: Jun 2008	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 .

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)