F5 power amplifier - Page 1019 - 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 31st January 2011, 10:10 AM   #10181
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Thanks Andrew; I have the followng resistances:-
Left channel P device D-S 52.2R S-D 55.6R N device D-S 51.2R S-D 48.5R

Right channel P device D-S 69.5R S-D 83.3R N device D-S 71.5R
S-D 61.4R.

I am using Fairchild Mosfets.
  Reply With Quote
Old 31st January 2011, 10:20 AM   #10182
diyAudio Member
 
bobodioulasso's Avatar
 
Join Date: May 2008
Marra, did you follow the right proceed for bias and offset setting?
That is without the bulb.
  Reply With Quote
Old 31st January 2011, 10:27 AM   #10183
anilva is offline anilva  India
diyAudio Member
 
Join Date: Mar 2004
Location: Bangalore
Quote:
Originally Posted by AndrewT View Post
1mW is ~-47dB ref maximum power of the F5 (50W into 4r0).
If one had noise at a level of -47dB one would be in tears after spending all that money.

Output offset is a "noise", if anyone will allow DC to be a noise. It certainly should not be there and certainly not considered acceptable.

If high efficiency speakers are being used with the F5 then it's even more important to minimise the output offset.
Andrew,

I if were to add a input capacitor to the F5 to prevent inadvertent DC to creep into the amp, is a 1 mfd, MKP a good choice, without compromising the bandwidth of the amp too much?

Thanks in advance.
__________________
DIY F5, F5T, F6, Aleph J, Fostex 206 based BLH, Altec Onken with 515B LF & 288H HF, Technics SP10 MKII & EMT938 turntables
  Reply With Quote
Old 31st January 2011, 11:09 AM   #10184
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Quote:
Originally Posted by bobodioulasso View Post
Marra, did you follow the right proceed for bias and offset setting?
That is without the bulb.
Yes this is without the bulb connected. On the left channel P1 does not alter the reading across the source resistor. P2 I can adjust. I raised the voltage to 0.12V and the offset changed so I turned it back to its lowest setting. With the right channel connected the p/s voltage started to rise then the 1amp q/b fuse popped.
  Reply With Quote
Old 31st January 2011, 11:19 AM   #10185
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Marra View Post
.........then the 1amp q/b fuse popped.
F1A?
Where is/are it/they located?
__________________
regards Andrew T.
  Reply With Quote
Old 31st January 2011, 11:38 AM   #10186
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Mains fused after the IEC inlet.
  Reply With Quote
Old 31st January 2011, 11:58 AM   #10187
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
What is your soft start circuit?
Do you need a slow charge circuit?
__________________
regards Andrew T.
  Reply With Quote
Old 31st January 2011, 12:04 PM   #10188
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Quote:
Originally Posted by AndrewT View Post
What is your soft start circuit?
Do you need a slow charge circuit?
The soft start circuit is one I bought from Avondale Audio that uses series resistors and relays which switch on in two stages.
  Reply With Quote
Old 31st January 2011, 12:07 PM   #10189
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Disconnect your amplifiers from the PSU.
Discharge the PSU
Start up your PSU using the F1A.
How often can you discharge and restart the PSU without nuisance blowing of the mains fuse?

How much VA does the F1A start up?

Can you link to details of the soft start?
__________________
regards Andrew T.
  Reply With Quote
Old 31st January 2011, 12:26 PM   #10190
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Soft Start Module for Mains Supply
Avondale Audio soft start module

Fully Automatic Timing Sequence - No more dimming lights, pops, clicks or blown fuses!

Operates in line fully automatically or manually with a low current switch.

Handles up to 1KW.

Includes an on-board mains current breaker / fuse, spark suppression and transient clamping.

Size: 97mm X 72mm Plus, no soldering
Soft Start PCB
Avondale Audio TPX pcb

Available in PCB only form for DIY audio projects.

Comes with list of required components and building guide.
  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
Rockford Fosgate Power 20001 bd amplifier power rating?? pachoorion Car Audio 8 8th May 2011 10:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 05:23 PM
McIntosh Power Amplifier Power Guard johnnyrt Solid State 2 23rd August 2007 10:22 PM
Output power for a power amplifier Progg70 Solid State 33 10th September 2006 08:44 AM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 04:06 PM


New To Site? Need Help?

All times are GMT. The time now is 02:00 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