F5 Turbo is posted - Page 23

bobodioulasso · 17th February 2012, 11:39 AM

This in case no diodes are used.
As diodes minimize losses.

AndrewT · 17th February 2012, 11:47 AM

I would expect the diodes to have at most a marginal effect on current contribution while the amp is operating in ClassA mode.

The diodes would in my opinion only provide significant increases in available current when output current is significantly more than the Max ClassA output.

If the diodes were already passing significant current in ClassA mode then I think you will find that they over-rule the stabilising effect of the source resistor.

triode_al · 17th February 2012, 11:55 AM

Quote:

Originally Posted by MASantos

Hw did you decide on the value of K and what does it represent?

Hiraga mentions a formula (le classe A)
Pmax = 2Vcc*a)^2
8*Rl

and uses a = 0,85 for bipolars, being the 'collector loss'; with FETS there is also inefficiency in driving, first of all a voltage component (not so much resistance) and there are source resiatances that dominate...
For his amp at 18V+/- he gets 15 watts; his formula at 33 volts this gives 50 watts too! I assume that this K is a similar 'drivability'.

bobodioulasso · 12:03 PM

At 3.5A, loss is 1.65v into source resistor let alone .
Diodes should keep about 0.65 volts across that resistor at the same current.
Which is 1volt less.

chchyong89 · 17th February 2012, 01:23 PM

Quote:

Originally Posted by AndrewT

I too get lost with the introduction of k.

Prior to that K, everything is correct.

...

ClassA output current.

I have assumed the power factor of the linear power supply at the range of 0.6~0.8

Shouldn't it be calculate in this way? If its wrong, please point me out

jacco vermeulen · 17th February 2012, 01:50 PM

peak output voltage level + voltage loss across the drain resistor + voltage to open up the output devices.

(and a little extra

)

biju55 · 17th February 2012, 03:38 PM

where can i buy the f5 turbo PCB s from ?

anilva · 17th February 2012, 04:28 PM

Quote:

Originally Posted by biju55

where can i buy the f5 turbo PCB s from ?

Just about now, people are discussing few layouts. They are not available to buy from anywhere. You can probably make your own PCB following the layouts discussed here.

bobodioulasso · 17th February 2012, 04:40 PM

If you are in a hurry, you might use Cviller F5 V2 boards from diyaudio store.

Variac · 06:20 PM

Or the F-5c V2 boards from the store

But they would both need some reworking..

17th February 2012, 12:01 PM	#224
bobodioulasso diyAudio Member Join Date: May 2008	At 3.5A, loss is 1.65v into source resistor let alone . Diodes should keep about 0.65 volts across that resistor at the same current. Which is 1volt less. Last edited by bobodioulasso; 17th February 2012 at 12:03 PM.

17th February 2012, 01:50 PM	#226
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, Rotterdam or Curaçao	peak output voltage level + voltage loss across the drain resistor + voltage to open up the output devices. (and a little extra ) __________________ Not so much,.......if it says "ZM" in the corner.

17th February 2012, 06:17 PM	#230
Variac diyAudio Editor Join Date: Dec 2001 Location: San Francisco, USA	Or the F-5c V2 boards from the store But they would both need some reworking.. __________________ 2013 Burning Amp Festival announced: Sunday, October 6th in S.F. We need Volunteers & sign-up's for what you're bringing! Last edited by Variac; 17th February 2012 at 06:20 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
F5 Turbo ............. if only !!!!!!	a.wayne	Pass Labs	23	21st January 2012 02:24 AM
F5 Cascoded - an alternative for my interest in the Balanced F5	NYCOne	Pass Labs	159	24th March 2011 05:23 AM
Turbo question	Thawach	Subwoofers	3	2nd March 2011 03:06 AM
E88CC turbo	revintage	Tubes / Valves	12	25th August 2010 11:52 AM
Zca ....turbo	sakis	Solid State	9	10th April 2010 04:49 PM


	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

17th February 2012, 11:39 AM	#221
bobodioulasso diyAudio Member Join Date: May 2008	This in case no diodes are used. As diodes minimize losses.

17th February 2012, 11:47 AM	#222
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I would expect the diodes to have at most a marginal effect on current contribution while the amp is operating in ClassA mode. The diodes would in my opinion only provide significant increases in available current when output current is significantly more than the Max ClassA output. If the diodes were already passing significant current in ClassA mode then I think you will find that they over-rule the stabilising effect of the source resistor.

17th February 2012, 03:38 PM	#227
biju55 diyAudio Member Join Date: Jul 2011 Location: Kuwait , India	where can i buy the f5 turbo PCB s from ?

17th February 2012, 04:40 PM	#229
bobodioulasso diyAudio Member Join Date: May 2008	If you are in a hurry, you might use Cviller F5 V2 boards from diyaudio store.

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read