F5T with 56V rails? - Page 2 - 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 2nd July 2013, 12:15 PM   #11
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Consider using a choke input filter?
That will drop your power supply voltage from 1.414 x to 0.9 x the AC.

Likely will give a better overall sound from the amp, imo, and maybe permit full class A operation.

Mooly, I don't quite recall how close to the rails it can swing, but the F5T has a diode across the source resistors that permits it to swing closer than normal to the rails at peak outputs... fwiw.


EDIT: fyi, that will give you ~100w RMS into 8 ohms... regardless you need monster heat sinks for any F5t...
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]

Last edited by bear; 2nd July 2013 at 12:29 PM.
  Reply With Quote
Old 3rd July 2013, 09:17 AM   #12
Leify is offline Leify  Sweden
diyAudio Member
 
Join Date: Apr 2013
I been thinking of a CLC power supply. What value of the choke would be ok? I have a couple of Hammond 2.5 mH that would be total 2 pcs chokes and 4 pcs 47000uF/100V per mono block.
  Reply With Quote
Old 3rd July 2013, 10:49 AM   #13
flg is offline flg  United States
diyAudio Member
 
flg's Avatar
 
Join Date: Jul 2005
Location: North East
A CLC supply is a Capacitor input supply. What Bear suggested is an Inductor input supply as in LC. It would produce a lower output voltage and a ripple with less higher order harmonics
__________________
"It was the perfect high end audio product: Exotic, inefficient, expensive, unavailable, and toxic." N.P.
  Reply With Quote
Old 3rd July 2013, 04:35 PM   #14
flg is offline flg  United States
diyAudio Member
 
flg's Avatar
 
Join Date: Jul 2005
Location: North East
Use dogpile.com(my favorite, or Google). Search on inductor input power supply. You will find better phrases to serach on from there? There is also another form of L input supply topology but I cannot recall the name. It involves the current in the inductor varying with the load cuurent???
MaybeZM has a comment???

Dogpile.com is better than Googrohh.com any day
__________________
"It was the perfect high end audio product: Exotic, inefficient, expensive, unavailable, and toxic." N.P.
  Reply With Quote
Old 6th July 2013, 09:29 AM   #15
Leify is offline Leify  Sweden
diyAudio Member
 
Join Date: Apr 2013
Thanks everyone. I will consider the LC design, but what is the difference to CLC in performance.
One more question is if the rails that will be about 50-52 V, is that to high voltage for the F5T V3?
  Reply With Quote
Old 8th July 2013, 11:39 AM   #16
Leify is offline Leify  Sweden
diyAudio Member
 
Join Date: Apr 2013
Any respond to the above questions?

Best regards

Leif
  Reply With Quote
Old 8th July 2013, 12:55 PM   #17
Leify is offline Leify  Sweden
diyAudio Member
 
Join Date: Apr 2013
I just found out that i bought the F5T V2 not V3, sorry my mistake. The recommendation is to have 32V rail voltage, but my rail voltage will be around 52V. Is that possible to run the V2 with that high rail voltage?

Best regards

Leif
  Reply With Quote
Old 8th July 2013, 01:30 PM   #18
ramallo is offline ramallo  Europe
diyAudio Member
 
ramallo's Avatar
 
Join Date: Nov 2004
Location: Madrid
Send a message via Skype™ to ramallo
Click the image to open in full size.
__________________
Happiness is a warm soldering iron
  Reply With Quote
Old 8th July 2013, 02:56 PM   #19
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
does the V2 have the facility to cascode the input transistors?
__________________
regards Andrew T.
  Reply With Quote
Old 8th July 2013, 03:11 PM   #20
Leify is offline Leify  Sweden
diyAudio Member
 
Join Date: Apr 2013
No, but V3 has.
  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
could the F5C or F5T be run at 40v rails? JZatopa Pass Labs 8 29th November 2012 03:44 AM
Benefits/Drawbacks of Dual rails vs Single Rails buzzforb Pass Labs 2 25th May 2011 01:06 PM
REPLACEMENT FOR ELNA CAPS 8200uF, 56v edusub Parts 3 29th June 2010 11:25 AM
Trying to source 8700uf @ 56V or substitutions CountryScience Parts 2 17th June 2009 08:24 PM
4x Elna Silmic 22000uF 56v Smoothing Capacitors (very rare) Kevinbd Swap Meet 13 23rd March 2006 11:57 AM


New To Site? Need Help?

All times are GMT. The time now is 08:32 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