Any upgrades for the Pearl Phono 2SK389 Problem? - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 17th February 2011, 02:25 PM   #1
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
Default Any upgrades for the Pearl Phono 2SK389 Problem?

A lot of people have had burned 2SK389 in the Pearl Phono.
I wanted to ask if anybody has found a solution for this Problem.
Some say that the problem occures on turn on and the large inrush current burns the 2SK389.
If this true can the parts be protected in any way?
  Reply With Quote
Old 17th February 2011, 02:36 PM   #2
diyAudio Member
 
d to the g's Avatar
 
Join Date: Aug 2006
Location: minimalopolis
For me it wasn't a turn on problem, but an issue when you hotswap (don't turn it off the pre and let the caps drain) output cables. The resolution was don't hotswap cables.
  Reply With Quote
Old 17th February 2011, 02:50 PM   #3
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
Well normally its not a good idea to swap cables when equipment is still powered on.
I am not sure when the 2SK389BL fail. If it is random or happens under specific conditions.
  Reply With Quote
Old 17th February 2011, 06:06 PM   #4
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Hi Promitheus,

long time no see!

Quote:
I wanted to ask if anybody has found a solution for this Problem.
Sure there is; replace them with 2x 2SK170BL that have a higher power dissipation; or, alternatively, replace them with 2x 2SK369GR with changed source resistors and enjoy slightly reduced distortion.

I think I posted the last one with values+measurements somewhere here in Passlabs quite some time ago.

The problem is that some high IDSS 2SK389 run a little too hot in the circuit for good reliability. You can also increase the source resistor and compensate the gain loss by adjusting the load resistor to some extent.

Hannes
  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
Turntables - Cartridge upgrades and Phono Preamps LordofTime Analogue Source 2 16th August 2010 03:30 PM
Thoughts for replacing the scarce 2SK389 in the pearl h_a Pass Labs 1 14th March 2010 08:58 AM
Problem with hum/buzz in Pearl Phono Buhl Pass Labs 11 10th June 2005 11:03 AM
Ordering 2SK389 transistors for Pearl Phono. Please help, which brand/spec? mattjk Pass Labs 5 16th February 2005 03:45 PM
Pearl Phono Problem -- Need Help!!! Mikelo Pass Labs 2 4th April 2004 09:38 PM


New To Site? Need Help?

All times are GMT. The time now is 01:44 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