F5 gate stopper value question. - 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 Yesterday, 06:50 PM   #1
diyAudio Member
 
Join Date: Dec 2011
Default F5 gate stopper value question.

I'm thinking about having another go at my F5. I've seen various schematics floating around. The “official” one in the F5T manual shows to use 100Ohm gatestopper before Q3 and Q4. However others show gatestoppers of 49Ohm. The use of gatestoppers are said to degrade the sound quality, so presumably a lower value is therefor preferred. But I suspect the 100Ohm value is chosen to be on the safe side of most eventualities.

My questions are, is it worth changing these out to 49Ohm (compared to 100Ohm) and what’s the risk of oscillation becoming a problem? Will the gain be higher with 49Ohm’s?
  Reply With Quote
Old Today, 04:59 AM   #2
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
Quote:
Originally Posted by stijn001 View Post
The use of gatestoppers are said to degrade the sound quality,


Not anywhere as much as you might think.

Quote:
But I suspect the 100Ohm value is chosen to be on the safe side of most eventualities.
Possibly.

Quote:
My questions are, is it worth changing these out to 49Ohm (compared to 100Ohm) and what’s the risk of oscillation becoming a problem? Will the gain be higher with 49Ohm’s?
No change in gain.

Gatestoppers on a mosfet amp can be anywhere from 47 ohm to about 680, where a higher value will do more to damp ultrasonic ringing (I.E., oscillation). Use whatever you happen to have. I like about 150ohm personally.
  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
Better way of installing gate stopper resistors? ridikas Solid State 3 9th April 2013 05:26 PM
Specific grid stopper question optimationman Tubes / Valves 22 10th March 2013 08:22 PM
Gate-stopper values ? sam9 Solid State 29 20th November 2012 10:16 AM
grid stopper question - 300B TubelabSE discomonkey Tubelab 6 28th April 2011 04:32 AM


New To Site? Need Help?

All times are GMT. The time now is 08:09 AM.


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