F5 power amplifier - Page 1221 - 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 16th April 2012, 10:38 AM   #12201
diyAudio Member
 
formula 22's Avatar
 
Join Date: Sep 2011
Location: El Triunfo
What preamp for F5?
thank you!
  Reply With Quote
Old 16th April 2012, 10:46 AM   #12202
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
You may not need a Pre-amplifier.

A volume control between the Source and the Power Amplifier may be all you will need.
__________________
regards Andrew T.
  Reply With Quote
Old 16th April 2012, 11:00 AM   #12203
diyAudio Member
 
formula 22's Avatar
 
Join Date: Sep 2011
Location: El Triunfo
Hi AndrewT!
I want to put the entrance to a simple tube line stage (Av<15dB) to bias amplifier F5 with a tube/valve-like sound.
Here for example with the tube pcc88.
thank you and cheers!

Last edited by formula 22; 16th April 2012 at 11:06 AM.
  Reply With Quote
Old 16th April 2012, 12:36 PM   #12204
fdlsys is offline fdlsys  South Africa
diyAudio Member
 
fdlsys's Avatar
 
Join Date: Nov 2010
Quote:
Originally Posted by formula 22 View Post
...F5 with a tube/valve-like sound.
If you haven't built the F5 (or listened to it) yet, then rather do that first. You might be surprised with what (to my ears!) sounds valve-ish, by design
I believe that non fully complementary nature of J74/K170 and IRFP devices can be "blamed" for that.
My 0.02 of local currency
  Reply With Quote
Old 16th April 2012, 03:58 PM   #12205
diyAudio Member
 
Join Date: Jun 2008
Location: HaiPhong
Default add 02x0.22R at out point both IRFP

Quote:
Originally Posted by Nelson Pass View Post
Very likely.

Dear Nelson Pass!
did you have idea to me ? Can I put more 2x0.22R-5w to separate circuit at OUT D gate of Q3,Q4 (keep R5,R7,R8,R6 like original circuit )and then betweent 2x0.22R will connect to speaker ???
is it will OK ????
  Reply With Quote
Old 18th April 2012, 07:43 AM   #12206
diyAudio Member
 
Join Date: Oct 2009
Location: Brunei
Startup procedures for F5.

I have almost finished my F5 build, and already tested the PSU. I get a nice +-24.0VDC on both rails, so that is looking good. Now I would like to fully test the F5.

I don't have a variac, or a set of spare speakers I can use for testing. I can of course use the lightbulb wire, but isn't that only used for testing the PSU? I have a bunch of DMM's and a scope at hand.

The big question is: when can I be sure that I am ready to connect them to my speakers and nothing blows up? Is 0 VDC on the outputs all I need to worry about?

EDIT: To be sure, I don't mean biasing... I have seen very good descriptions of the process on the forum. I am just looking for some checklist that I need to run before hooking it up to my main speakers...

Last edited by studiostevus; 18th April 2012 at 07:45 AM.
  Reply With Quote
Old 18th April 2012, 08:00 AM   #12207
diyAudio Member
 
noSmoking's Avatar
 
Join Date: May 2010
Location: Texas
Hi studiostevus,
I bought a 8 ohm load resistor,just for that It's rated for 100 watts ,so you can connect it instead of your speakers and watch the output on your scope,It is possible to use a small fuse inline with the speakers so it blows and not your speaker coils,I connect a freq. gen at 1000hz and run up the input voltage slowly and watch the output on the scope,you can also meter your rails DC and lower the fuse in your power supply just to test,check bias often until it gets to operating temp ,I hope this help ,a small set of test speakers can be obtained cheaply at yard sales ,radio shack or parts express,,,,,,Good luck
  Reply With Quote
Old 18th April 2012, 09:09 AM   #12208
diyAudio Member
 
Join Date: Jun 2008
Location: HaiPhong
Quote:
Originally Posted by studiostevus View Post
Startup procedures for F5.

I have almost finished my F5 build, and already tested the PSU. I get a nice +-24.0VDC on both rails, so that is looking good. Now I would like to fully test the F5.

I don't have a variac, or a set of spare speakers I can use for testing. I can of course use the lightbulb wire, but isn't that only used for testing the PSU? I have a bunch of DMM's and a scope at hand.

The big question is: when can I be sure that I am ready to connect them to my speakers and nothing blows up? Is 0 VDC on the outputs all I need to worry about?

EDIT: To be sure, I don't mean biasing... I have seen very good descriptions of the process on the forum. I am just looking for some checklist that I need to run before hooking it up to my main speakers...
dear ! about blows up speaker : you can check I1,I2 must be the same value at bothside of amp.
  Reply With Quote
Old 18th April 2012, 09:51 AM   #12209
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
the bulb tester can and should be used to power up every change or modification to a mains powered project.
The bulb tester cannot be used to bias up the output stage. But by then all the modifications and additions will have been completed and tested and proved to be correct.

If you make a further modification after you have biased up your F5 then I strongly suggest you reduce bias back to zero and power up via the bulb tester so that you are proving to yourself that the modification has not turned a perfectly good F5 into a bomb. Then rebias.
__________________
regards Andrew T.
  Reply With Quote
Old 18th April 2012, 11:08 AM   #12210
diyAudio Member
 
Join Date: Oct 2009
Location: Brunei
Ok, so the procedure would be:

1. Setting all trimmers to 0Ohms - proceed to #2

2. Power up with bulb tester - anything to measure at this stage?

3. Power up with normal wire and proceed with #4

4. Biasing procedures - No load - If everything seems ok and stable, proceed to #5.

5. Test with 8Ohm resistor or test speakers and scope - measure DC offset and bias over longer period. If everything is stable, proceed to #6

6. Declare the amp safe and move over to main speakers

Correct?
  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 02:38 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