F5 power amplifier - Page 1278 - 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 6th January 2013, 03:11 PM   #12771
diyAudio Member
 
Join Date: Feb 2005
Location: Melbourne
I couldn't sleep at night if I didn't ensure that my precious speakers would get fried if a rail/fet, etc happened - relays, or opto driven power fets, are inaudible in the system. This is an external dc protection package, not part of the amp's design - you can get them anywhere.

The high value, deep etched Panasonics have a 'sound of their own' and the smaller bipass, particularly directly at the power fets is most effective - Nichicons have a "better" sound than the large value Panasonics.

The GB Block bridges use standard diodes and are very handy things - unfortunately, they're also quite noisy things and even tho you have a large value power caps, this "noise" still gets thru and adds "an edge" to the sound - the Shottky diodes don't have this "edge" to the sound, so I call this a "better" sound. Unfortunately, they're not cheap and with 1 bridge per channel it does add up a bit (same if you use discrete diodes) bit the benefits are obvious.

The current limiting components do change the sound slightly - some people prefer it.

The thermistor is there to increase the bias on the O/P Fets as they warm up - not much to do with thermal protection.

I can't clearly see your jfets in the photo but it doesn't seem like you've connected them together for thermal tracking - heatsink goo and a clip (or tie wrap) is essential.

As an old "Ham' you'll be quite comfortable with the idea of making a device to interupt the mains supply to the amp by adding a series globe to reduce the mains voltage, yes? if you haven't access to a variac.

On one of my thick Ali front panels I got the local platers to etch a pseudo dutch pewter surface on it and then added a simple transparent letter decal over that - looks quite neat - the proper grooved lettering is a better finish but a bit pricey with the coloured infil and the surface finish, etc.

Polished wood front panels look okay with the little leds showing through it.

A good amp, well worth a bit of extra effort.
__________________
... jh
  Reply With Quote
Old 6th January 2013, 07:10 PM   #12772
diyAudio Member
 
Join Date: Jun 2005
Location: drachten
Default bias

Hi There!
I fired my cviller boards F5c on and got 2.7 volts on R11 and on the speakerterminals dc is running up from zero to 300 mv and still running up more. The mosfets are getting burning hot and there came some smoke from R11 at first. I know the F5c boards are for the turbo version, but I also read that I can use it for normal use. What did I wrong? Is there somebody on the forum who can help me? Than my thankings will be great. Grtz Teake
  Reply With Quote
Old 7th January 2013, 03:17 PM   #12773
diyAudio Member
 
Join Date: May 2011
Location: France
Hi all,

maybe a stupid question, but... I have got in my box many capacitors I want to use to build a power supply for the F5. but I haven't got 33000uf, so I'm thinking of put in parallele some capacitors to get around 33000uf. Is it a problem to wire in parallele capacitors with different values ? for example I'm thinking of using a 15000uf, with 10000uf and a 6800uf. My transformer is a 700va from my box too.

Thank for your help.

Last edited by moonLeo; 7th January 2013 at 03:29 PM.
  Reply With Quote
Old 7th January 2013, 04:16 PM   #12774
Marra is offline Marra  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Near Lincoln
Quote:
Originally Posted by intense-tavda View Post
Hi There!
I fired my cviller boards F5c on and got 2.7 volts on R11 and on the speakerterminals dc is running up from zero to 300 mv and still running up more. The mosfets are getting burning hot and there came some smoke from R11 at first. I know the F5c boards are for the turbo version, but I also read that I can use it for normal use. What did I wrong? Is there somebody on the forum who can help me? Than my thankings will be great. Grtz Teake
Did you make sure that the trimmers were set to zero? Sorry if stating the obvious.
I used cvillers pcbs for a standard F5.
  Reply With Quote
Old 7th January 2013, 04:47 PM   #12775
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally Posted by moonLeo View Post
Hi all,

maybe a stupid question, but... I have got in my box many capacitors I want to use to build a power supply for the F5. but I haven't got 33000uf, so I'm thinking of put in parallele some capacitors to get around 33000uf. Is it a problem to wire in parallele capacitors with different values ? for example I'm thinking of using a 15000uf, with 10000uf and a 6800uf. My transformer is a 700va from my box too.

Thank for your help.
just go for it
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 7th January 2013, 07:55 PM   #12776
diyAudio Member
 
Join Date: Jun 2005
Location: drachten
Default F5

Hi There!
Thanks for the answer. I did not put the pots to zero at first but second time I did. And still the same measurings. For R 1 and R2 I have 10ohm 20 watt caddocks. Could that be the problem also? Is it bether to take a lower wattage? Thanks for the answer, grtz Teake
  Reply With Quote
Old 7th January 2013, 07:58 PM   #12777
Renron is offline Renron  United States
diyAudio Member
 
Renron's Avatar
 
Join Date: Jan 2007
Location: Sacramento
From my (very) limited understand of ripple reduction, if the capacitors are correct voltage, same type, the largest size uF should be closest to the rectifier(s). Smallest closest to the F5 boards.
__________________
"If it doesn't work properly, hope it catches on fire"- Nelson Pass @ BA3
"I fired up the prototype. Literally." The Prophet Pass.
  Reply With Quote
Old 7th January 2013, 08:20 PM   #12778
diyAudio Member
 
GentryBa's Avatar
 
Join Date: Oct 2011
Location: Bavaria
hi there!

any possibility for a stereo f5t with 530VA / 30V r-core transformer?
maybe for V2 its enough power?
30VAC should gave me over 40VDC- would that be ok?

*edit*
oops, wrong thread- sorry for that

Thanks!
Best regards,
Matthias
  Reply With Quote
Old 10th January 2013, 03:56 PM   #12779
diyAudio Member
 
Join Date: Dec 2009
Location: Switzerland and Mississippi
As mentioned in the thread earlier, Would quick set epoxy work for thermal bonding glue to connect thermistor to FETS, or ok to just have them touching?
  Reply With Quote
Old 10th January 2013, 04:19 PM   #12780
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Epoxy would be fine.

  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 11:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 06:23 PM
McIntosh Power Amplifier Power Guard johnnyrt Solid State 2 23rd August 2007 11:22 PM
Output power for a power amplifier Progg70 Solid State 33 10th September 2006 09:44 AM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 05:06 PM


New To Site? Need Help?

All times are GMT. The time now is 12:38 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