F5 Turbo Builders Thread - Page 4 - 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 22nd February 2012, 11:32 AM   #31
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Means i visited your thread more than take a minute to respond to Bksabbathical's post, aka apology.
__________________
The buck stops Here
  Reply With Quote
Old 22nd February 2012, 11:35 AM   #32
diyAudio Member
 
Join Date: Jan 2010
Location: Harrow, UK
Ah OK :smile:
  Reply With Quote
Old 22nd February 2012, 03:20 PM   #33
diyAudio Member
 
Bksabath's Avatar
 
Join Date: Dec 2007
Tanks Jacco
I will have to digest that.

In the mean time have a pint on me.

for now I am going to crak open a botle of apple wine is only 19 proff but not sometink one can get legaly

So duble the drive currants I going to think about 2 Jfets in parralel bit.

By the way If you ever this side of the water Just give us a call I am going to keep a botle of Nardini for that
  Reply With Quote
Old 23rd February 2012, 08:56 PM   #34
ra7 is offline ra7  United States
diyAudio Member
 
Join Date: Feb 2009
Blog Entries: 1
That was quite brilliant Jacco! Thanks!
  Reply With Quote
Old 23rd February 2012, 10:17 PM   #35
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
In the nut house, they said i was the smartest of the bunch of idiots.
(but hey, ever shagged a sane psychology major ?)
__________________
The buck stops Here
  Reply With Quote
Old 24th February 2012, 10:05 AM   #36
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Quote:
Originally Posted by Bksabath View Post
regarding this
Part Deuce (bigelow) :

For cap size, also read the Pass A40 paper, the WCR part.
W is 2 *Pi * mains frequency, so 2*Pi*f is ~314 for 50Hz and 8 Ohm.
(for full wave rectification : ripple current = ripple voltage * 2WC)

Other post :
The FQA36P15/FQA28N15 look the better combo for Ciss & transconductance.
They're also good for 1/4 more bias current (the lower power one sets the pace for dissipation)
Not a garantee that they'll sound better than the other ones.
(thanks to Patrick's mini group buy, i still have plenty of matched FQA19N/12P left at bottom rate, so easy for me to say)
__________________
The buck stops Here

Last edited by jacco vermeulen; 24th February 2012 at 10:17 AM.
  Reply With Quote
Old 24th February 2012, 10:10 AM   #37
diyAudio Member
 
Join Date: Jun 2006
More power than what F5 can provide would be welcome for my speakers. Having F5 in hand, I’m looking for an easy way out, which -per my very limited understanding- seems available. I’m considering the following.

In the F5 Turbo text:
Increasing the power supply voltage is the obvious way to get more power out of an F5. You can simply raise the supply rails to +/-32 Volts and get 50 watts into 8 ohms right away without other modification. 24 V AC secondaries on the power transformer will do it. Don't forget to use higher voltage power supply capacitors. Probably you should also upgrade R9 through R12 to 5 watt resistors. Depending on your heat sinking, you will probably want to adjust the bias so that the power transistors don't run too hot.
I have Peter Daniel boards and 36V power supply caps. Am I ok, if just I swap the transformer to 2x24V 500VA (to replace 2x18V 400VA) and above named resistors to 5W? Or is there some downside I should be aware of, except that I need to adjust the bias current with the trimpots per heat?

Text also states:
You can remove the current limiting (Q5, Q6, R15 to R18 of the original) as long as you are cautious about shorting the output.
Am I to get what benefit out of this? I do understand that it brings along a risk, but I’d assume there’s something positive about it as well. Or is there?

Further:
You may also notice that the feedback resistors R7 through R10 have been increased, increasing the amplifier's gain to about 22 dB and decreasing the amount of feedback by about 7 dB. If we are going to put out more power it is appropriate to have some more gain, and it gives us more margin for feedback stability – the amplifier still is flat to about 800 Khz.
In F5 these resistors are 100ohm and in Turbo V1 220ohm. Should I change these as well, if I’m to follow the simplified path described above? To 220ohm? Or is this relevant only if I’m to use double output devices (i.e. per V1 turbo)?

Comments welcome.
  Reply With Quote
Old 24th February 2012, 10:18 AM   #38
diyAudio Member
 
Join Date: May 2005
Location: Lisbon Portugal
Quote:
Originally Posted by Juuso View Post
More power than what F5 can provide would be welcome for my speakers. Having F5 in hand, I’m looking for an easy way out, which -per my very limited understanding- seems available. I’m considering the following.

In the F5 Turbo text:
Increasing the power supply voltage is the obvious way to get more power out of an F5. You can simply raise the supply rails to +/-32 Volts and get 50 watts into 8 ohms right away without other modification. 24 V AC secondaries on the power transformer will do it. Don't forget to use higher voltage power supply capacitors. Probably you should also upgrade R9 through R12 to 5 watt resistors. Depending on your heat sinking, you will probably want to adjust the bias so that the power transistors don't run too hot.
I have Peter Daniel boards and 36V power supply caps. Am I ok, if just I swap the transformer to 2x24V 500VA (to replace 2x18V 400VA) and above named resistors to 5W? Or is there some downside I should be aware of, except that I need to adjust the bias current with the trimpots per heat?

Text also states:
You can remove the current limiting (Q5, Q6, R15 to R18 of the original) as long as you are cautious about shorting the output.
Am I to get what benefit out of this? I do understand that it brings along a risk, but I’d assume there’s something positive about it as well. Or is there?

Further:
You may also notice that the feedback resistors R7 through R10 have been increased, increasing the amplifier's gain to about 22 dB and decreasing the amount of feedback by about 7 dB. If we are going to put out more power it is appropriate to have some more gain, and it gives us more margin for feedback stability – the amplifier still is flat to about 800 Khz.
In F5 these resistors are 100ohm and in Turbo V1 220ohm. Should I change these as well, if I’m to follow the simplified path described above? To 220ohm? Or is this relevant only if I’m to use double output devices (i.e. per V1 turbo)?

Comments welcome.
There is nothing wrong with replacing the transformer, and the required parts, but if you do that and don't want new boards, you could wire another pair of output mosfets to share the heat dissipation.

Regarding the speaker protection circuitry, some people report that amplifiers sound better without this parts. You can try it yourself, if you hear a difference leave them out, if not, put them back in.
  Reply With Quote
Old 24th February 2012, 10:38 AM   #39
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Quote:
Originally Posted by Juuso View Post
Or is this relevant only if I’m to use double output devices
No, and you quoted the reason why yourself.
__________________
The buck stops Here
  Reply With Quote
Old 24th February 2012, 11:53 PM   #40
alazira is offline alazira  United States
diyAudio Member
 
alazira's Avatar
 
Join Date: Jun 2007
Location: Las Vegas
Blog Entries: 1
Default power supply

Hi,

Concerning the F5Turbo power supply:

(1) I was wondering if there is some advantage in the center-tap style wiring of the secondaries vs the original F5 power supply that uses bridge diodes (other than needing four fewer diodes and one less thermistor on the primaries)?

(2) The paper says "The power transformer needs to be VA rated at least twice the actual dissipation of the amplifier." Can someone please give me an example of this calculation using V1 or V2?

(3) Would using a bleed resistor like in the original have a deleterious effect?
Attached Images
File Type: jpg F5 Turbo Power Supply.jpg (206.2 KB, 1996 views)
File Type: jpg F5 Power Supply.jpg (131.5 KB, 1656 views)
  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 Circuit Boards chchyong89 Pass Labs 2347 14th July 2014 02:19 PM
B1 builders thread Bas Horneman Pass Labs 696 14th July 2014 12:57 PM
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


New To Site? Need Help?

All times are GMT. The time now is 10:30 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