F5 Turbo Circuit Boards - Page 179 - 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 21st September 2012, 07:23 PM   #1781
beetle is offline beetle  Germany
diyAudio Member
 
Join Date: Mar 2008
3A bias is coming very close to that. Serious heat sinks from fischer or so are really costly. Can buy only two for a modushop case.
  Reply With Quote
Old 21st September 2012, 08:11 PM   #1782
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
are you allowing for 3A bias at +-24Vdc from each half of the balanced amplifier?
i.e. 288W dissipation per channel.

3A bias gives ~ 6Apk of ClassA and results in 36W of ClassA into 2r0. This when feeding a 4r0 load from the two halves of the balanced is roughly 72W of ClassA into 4r0. Double the power into double the load impedance.

Working back from your 200W into 4r0 balanced, needs 100W into 2r0 from each half.

That requires a ClassAB output of 20Vpk and 10Apk. Probably a sensible target from +-24Vdc rails biased to a total current of 6A.
__________________
regards Andrew T.

Last edited by AndrewT; 21st September 2012 at 08:13 PM.
  Reply With Quote
Old 21st September 2012, 08:18 PM   #1783
a.wayne is offline a.wayne  United States
Sin Bin
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by AudioSan View Post
beetle. (bias x2) x (bias x2) x impedance /2.
so say 2A bias. it is 4 x 4 x 2 / 2 = 16W class A at 2ohm
or 64 W @8ohm

Quote:
Originally Posted by beetle View Post
So ~3A bias 24V rails then. I would assume that Modushop 5U 500 has not the right sinks for 576W per channel. Or does it?

1kva 18V toroid will be costly. Any good source in Europe?

I would expect a total power of up to 200W in 4 ohm Class B and 36W class A. Right?
32 watts ...
  Reply With Quote
Old 21st September 2012, 08:30 PM   #1784
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I understood he wanted to bridge the outputs as described in options of the F5t.
That's what I assumed in my response of post1782
__________________
regards Andrew T.
  Reply With Quote
Old 21st September 2012, 08:48 PM   #1785
beetle is offline beetle  Germany
diyAudio Member
 
Join Date: Mar 2008
Quote:
Originally Posted by AndrewT View Post
are you allowing for 3A bias at +-24Vdc from each half of the balanced amplifier?
i.e. 288W dissipation per channel.

3A bias gives ~ 6Apk of ClassA and results in 36W of ClassA into 2r0. This when feeding a 4r0 load from the two halves of the balanced is roughly 72W of ClassA into 4r0. Double the power into double the load impedance.

Working back from your 200W into 4r0 balanced, needs 100W into 2r0 from each half.

That requires a ClassAB output of 20Vpk and 10Apk. Probably a sensible target from +-24Vdc rails biased to a total current of 6A.
Aren't the speakers seeing the double voltage when bridged?
  Reply With Quote
Old 21st September 2012, 09:20 PM   #1786
diyAudio Member
 
Join Date: Feb 2009
[QUOTE=a.wayne;3173877]or 64 W @8ohm

correct
  Reply With Quote
Old 22nd September 2012, 07:14 AM   #1787
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by beetle View Post
Aren't the speakers seeing the double voltage when bridged?
Quote:
Originally Posted by AudioSan View Post
.............correct
yes,
how does knowing that help you?

Do you understand how an amplifier works?
Do you know the difference between ClassA operation and that for ClassAB?
Do you know how a bridged and balanced amplifier operates?
__________________
regards Andrew T.
  Reply With Quote
Old 22nd September 2012, 10:51 AM   #1788
beetle is offline beetle  Germany
diyAudio Member
 
Join Date: Mar 2008
Bridging means that one amp is inverted or the signal. Current will remain the same but voltage is double.

Besides this a little, still learning. In this case we have a push pull amp. In this particular F5 design the first stage is splitting the signal in two halves. One inverted. The F5 is class A up to the bias. Then it transitions to class B. I think this describes it well: Push pull amplifier, working and theory. Class A , Class B , Class AB circuit diagram

Still learning.
  Reply With Quote
Old 22nd September 2012, 11:51 AM   #1789
diyAudio Member
 
Join Date: Feb 2009
andrew. why do you quote my answer in there??
i answered wayne.

but to answer how it helps to know that.
it makes a huge differnce on the dissipation.
  Reply With Quote
Old 22nd September 2012, 04:32 PM   #1790
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
you told him "correct".
I agreed, "yes".

But does the questioner know what he is doing?
Now that Beetle has posted 1788, it is obvious he does not have a clue.
__________________
regards Andrew T.

Last edited by AndrewT; 22nd September 2012 at 05:01 PM.
  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 clone boards (inc PSU boards) Tazzz Swap Meet 39 7th June 2014 07:02 AM
F5 Turbo is posted Nelson Pass Pass Labs 635 6th April 2014 10:51 AM
F5 turbo problems Rob Dingen Pass Labs 17 11th January 2013 08:38 PM
F5 Turbo ............. if only !!!!!! a.wayne Pass Labs 23 21st January 2012 02:24 AM
UGS Boards and F5 boards DUC985 Swap Meet 0 7th January 2009 07:21 PM


New To Site? Need Help?

All times are GMT. The time now is 07:58 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