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 24th May 2013, 06:16 PM   #131
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Andrew,
I am not saying that it might not make things more stable, but was is the signfigance in performance gains if you are operating with a stable amp? Do you expect decreased distortion and if so, how much? IF degenerating them and lowering overall temp, do we avoid some of these effects. Does cascoding them further diminish the effects, as it lowers overall temp. Is there any data showing the difference between coupled and non- coupled performance. I know EUVL looked into it and made a heatsink, but don't know if he had data showing the difference.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 18th June 2013, 02:58 AM   #132
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Would you be so kind 6L6 as to show us how you have your F5t wired now ? which way worked best with those diyaudio boards ? and how did u fix your ground loop!
Im having some issues still with the ground loops or Hum, whichever it is!
nothing beats seeing visually how it should be done! from the masters themselves ;-)

I have ground going to the gain stages first then from there to Pch and Nch boards.

atleast i got the bias problem sorted now
50 DEG, 0.31 bias
lovely!
__________________
www.Rixsta.co.uk Free music recorded by me/DIY pics Currently Selling, amps=Zen V4, Zen-lightenment‎, Jean Hiraga 20w, F5, F5T

Last edited by Rixsta; 18th June 2013 at 03:03 AM.
  Reply With Quote
Old 9th December 2013, 12:55 AM   #133
diyAudio Member
 
Join Date: Nov 2010
Location: Quebec
Hi Jim,

I'm ordering parts to build F5T. Can you tell me which is the part number of the thermal shutoff you used? Is it really needed? And what is the height of the board stand off you use to allow installation of the mosfet?

Thanks
  Reply With Quote
Old 9th December 2013, 02:06 AM   #134
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
I honestly don't know the part# of the thermal. It was a suggestion from another member as I found it imposible to search for on Mouser. No, you don't really need it.

5mm M3 or taller standoffs should be enough. For what it's worth, because there is so little on the small PCB that holds the Mosfets and diodes, you don't really need standoffs for those boards. It certainly doesn't hurt to have them however.
__________________
Illustrated Build Guides - Pass F4 - Pass B1 - Pass F5 - Pearl 2 - O2 HPA - Hagerman Bugle 2 - Pass Aleph J - Me at BA '13
  Reply With Quote
Old 9th December 2013, 02:41 AM   #135
diyAudio Member
 
Join Date: Nov 2010
Location: Quebec
Thanks Jim, so it will be without thermal shut off and without board stand off. I like easy and affordable solutions like this.
  Reply With Quote
Old 9th December 2013, 04:38 AM   #136
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
You will still need something to hold the front-end board...
__________________
Illustrated Build Guides - Pass F4 - Pass B1 - Pass F5 - Pearl 2 - O2 HPA - Hagerman Bugle 2 - Pass Aleph J - Me at BA '13
  Reply With Quote
Old 6th January 2014, 10:02 PM   #137
Mallard is offline Mallard  Germany
diyAudio Member
 
Join Date: Jan 2003
Location: Germany, Luenen
Hi 6L6,

I'm sorry to ask this but I don't understand the different directions of your arrows on P1 and P2. My understanding was anticlockwise decreases resistance and clockwise inreases resistance. Why did you do P1 and P2 in a different way?
I remember my F5 both pots P1 and P2 where handled in the same way.
And it was my plan for my new F5T V.2 -> I turn both pots anticlockwise until I can hear a little "klick" and than start the biasing procedure.

Regarding P3: Can't I just count the whole turns from Zero to Max and then put it exactly in between? When I count correctly in total it's 62 turnings, so set it to 31 and I should have pretty much the mid of 200Ohm.

Again I'm sorry for asking such low skill questions but I better ask twice easy questions rather than blow up everything just because of a misunderstanding.


Quote:
Originally Posted by 6L6 View Post


Click the image to open in full size.

There are a couple of things that need to be done to the FE board when you are stuffing it -

1) Set P3 to it's middle value - with an ohmmeter measure from the wiper and one leg to the other leg and set the approximate middle. (about 100 ohm) Now turn the pot around, measure from the other leg and wiper to the first leg and set it to the middle value. You will find that as you flip the pot you will eventually find the equal setting. But as the pot track isn't exactly 200 ohms long, the null will not be exactly 100. (it will be very close, however.)

2) Turn the bias pots (P1, P2) all the way down. Measure that before soldering. Then make a mark on the pot to show which way increases the resistance.

  Reply With Quote
Old 6th January 2014, 11:19 PM   #138
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
The pots are mounted to match the PCB. Anticlockwise is only "down" if the PCB and pot are arranged to react that way. So "Down" will be whatever direction gives you the lowest reading across TP1-TP2 and TP3-TP4.

Yes, you can take P3 all the way to one direction and then go back halfway.
__________________
Illustrated Build Guides - Pass F4 - Pass B1 - Pass F5 - Pearl 2 - O2 HPA - Hagerman Bugle 2 - Pass Aleph J - Me at BA '13
  Reply With Quote
Old 7th January 2014, 09:55 AM   #139
Mallard is offline Mallard  Germany
diyAudio Member
 
Join Date: Jan 2003
Location: Germany, Luenen
Ok, that means on the gain stage pcb v.2.2 before starting biasing process :
P2 has to be turned anticlockwise to Zero (between TP1-TP2) and
P1 has to be turned clockwise to zero (between TP3 - TP4)

---> CORRECT?



Quote:
Originally Posted by 6L6 View Post
The pots are mounted to match the PCB. Anticlockwise is only "down" if the PCB and pot are arranged to react that way. So "Down" will be whatever direction gives you the lowest reading across TP1-TP2 and TP3-TP4.

Yes, you can take P3 all the way to one direction and then go back halfway.
  Reply With Quote
Old 7th January 2014, 11:28 AM   #140
diyAudio Member
 
Join Date: Jan 2010
Location: Harrow, UK
Mallard,

On the current store boards the pots operate in the same direction. i.e. I rotated the rightmost pot so that they both zero anticlockwise (or clockwise, can't remember and I'm away from home at the moment so I don't have access to the drawings).
  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
F5 Turbo is posted Nelson Pass Pass Labs 635 6th April 2014 10:51 AM
F5 turbo heatsinks AudioSan Pass Labs 21 31st August 2013 01:47 PM
F5 turbo problems Rob Dingen Pass Labs 17 11th January 2013 08:38 PM
Best way to tune in BIAS F5 V2 Turbo Blink_PT Pass Labs 17 4th January 2013 10:40 AM
F5 Turbo ............. if only !!!!!! a.wayne Pass Labs 23 21st January 2012 02:24 AM


New To Site? Need Help?

All times are GMT. The time now is 06:57 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