F5 Turbo Builders Thread - Page 186 - 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 14th May 2013, 07:00 PM   #1851
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Yes, I remember reading you saying this on another post somewhere.

Thanks Im thinking of going this way with good relays OR just putting appropriate fuses on the secondary AC or after Caps DC ?

Im Presuming with the right fuses, they would blow fairly fast and the speaker may see DC for a second or two.

Atleast fuses are some form of protection without having to worry about sound quality issues.
__________________
www.Rixsta.co.uk Free music recorded by me/DIY pics Currently Selling, amps=Zen V4, Zen-lightenment‎, Jean Hiraga 20w, F5, F5T
  Reply With Quote
Old 15th May 2013, 02:20 PM   #1852
WalterW is offline WalterW  Netherlands
diyAudio Member
 
Join Date: Oct 2012
Location: Utrecht
Two questions:
- When I power up my new F5Turbo v2 it consumes around 300 Watt total and after an hour or so they stabilize around 350 Watt ( that is the bias I set them to when they were hot). Is this a too big difference ?
The R11 and R12 resistors which are in series with the NTCs are already lowered to 1k21 instead of 2k2. Should I lower them further or even short them?

- One transformer starts sometimes humming for a few seconds, or a minute and then the hum dissapears slowly. With a cold and warm amp, very unpredictable... The amps bias and powerconsumption does not change when humming.
I noticed this behaviour already testing the transformers without load.
What is the reason of this? What can be done?

Walter
__________________
Pass F5, F5Tv3, ACA, Aleph J, DDDAC1794, DCB1, BA3-preamp, VFET CSX1.
  Reply With Quote
Old 15th May 2013, 02:25 PM   #1853
6L6 is online now 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
Your power consumption seems normal.

The important question is what is your measured cold bias and what does it change into when it's warm?
  Reply With Quote
Old 15th May 2013, 02:40 PM   #1854
diyAudio Member
 
Join Date: Sep 2012
Walter, what kind/brand/rating transformers are you using?
  Reply With Quote
Old 15th May 2013, 03:06 PM   #1855
oiphy is offline oiphy  Norway
diy newbie
diyAudio Member
 
oiphy's Avatar
 
Join Date: Sep 2011
Location: norway
- One transformer starts sometimes humming for a few seconds, or a minute and then the hum dissapears slowly.

dc in mains?
__________________
" If you're going throu hell, keep going"
  Reply With Quote
Old 15th May 2013, 03:47 PM   #1856
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Default Transformer Rating

When building the v3, it's recommended to use a transformer with twice the rated VA. I have two Antek AS-4218 rated at 400v or approx. 11A each.
With secondaries in serial for 36v, will the secondaries deliver half the current?

Will the transfos be enough for mono block v3 F5? Would 5-6 amps be enough to drive 1 channel to 100w?

Thanks,

Vince
__________________
I build, therefore I am.
  Reply With Quote
Old 15th May 2013, 04:01 PM   #1857
WalterW is offline WalterW  Netherlands
diyAudio Member
 
Join Date: Oct 2012
Location: Utrecht
Quote:
Originally Posted by ijscobar View Post
Walter, what kind/brand/rating transformers are you using?
Two new Amplimo's 98016 : 625VA, 2 x 25V, 2 x 12.5 A, made in UK.
Total of 1.25 KVA for 320 Watt class A dissipation.
So 4 times the dissipation, which is good according to Papa
__________________
Pass F5, F5Tv3, ACA, Aleph J, DDDAC1794, DCB1, BA3-preamp, VFET CSX1.
  Reply With Quote
Old 15th May 2013, 06:04 PM   #1858
WalterW is offline WalterW  Netherlands
diyAudio Member
 
Join Date: Oct 2012
Location: Utrecht
Quote:
Originally Posted by oiphy View Post
- One transformer starts sometimes humming for a few seconds, or a minute and then the hum dissapears slowly.

dc in mains?
DC in the 230 Volts? Is that possible?
__________________
Pass F5, F5Tv3, ACA, Aleph J, DDDAC1794, DCB1, BA3-preamp, VFET CSX1.
  Reply With Quote
Old 15th May 2013, 06:17 PM   #1859
oiphy is offline oiphy  Norway
diy newbie
diyAudio Member
 
oiphy's Avatar
 
Join Date: Sep 2011
Location: norway
Default afraid so.

Quote:
Originally Posted by WalterW View Post
DC in the 230 Volts? Is that possible?
yep..... and it saturates the trafo so it starts humming..
there's an easy fix with two diodes and two caps I believe... edit : AndrewT posted a link to it a while ago...


edit: http://www.federalpacific.com/litera...ormernoise.pdf maybe some help here
__________________
" If you're going throu hell, keep going"

Last edited by oiphy; 15th May 2013 at 06:46 PM.
  Reply With Quote
Old 15th May 2013, 06:20 PM   #1860
WalterW is offline WalterW  Netherlands
diyAudio Member
 
Join Date: Oct 2012
Location: Utrecht
Quote:
Originally Posted by 6L6 View Post
Your power consumption seems normal.

The important question is what is your measured cold bias and what does it change into when it's warm?
Hi 6L6,

I measured cold exact 0.2 volts over the 0,1 Ohm resistor in each PSU rail.
So cold 2.0 Ampere = 1.0 Ampere per MOSFET.
Over the P channel 0.22 Ohm sourceresistors I measured 0.217 V and 0.212 Volt, so that's indeed around 1 Ampere / MOSFET.

When the Amp is hot, I measure 0.252 Volts over the 0.1 Ohm PSU resistor, so my beloved 2.5 A per rail. The 0.268 V and 0.262 Volts over the sourceresistors confirm this. Around 1,25 Amp / MOSFET.

So that's what the bias changes from 20 degrees Celsius to 52 degrees Celsius.
Is that too much?
__________________
Pass F5, F5Tv3, ACA, Aleph J, DDDAC1794, DCB1, BA3-preamp, VFET CSX1.
  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 04:59 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