F4 power amplifier - Page 253 - 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 18th June 2008, 06:13 PM   #2521
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Quote:
Originally posted by Zen Mod



well - I have another impression - they all were just looking WTF Papa is doing with that amp .......


No more toys for that gentleman


Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 18th June 2008, 06:16 PM   #2522
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
My tall tower has worked very well, but it is 6" square, and allows a lot of air flow through it- in fact more than normal because of the stack effect. A finned heatsink won't get this kind of air flow as the channels are relatively small.. Note that Nelson uses his fins horizontally, offending all purists, and they work fine. The tower gives a small footprint and like a big V8 engine, it works by having lots of inches! - about 25% more surface area than Nelson's commercial F4's. Magura predicted disaster for it and insisted on additional heatsinks, but it works fine even after I scraped the extra sinks off... I am rebuilding it for a second time and it is finally of a quality that I can live with. The show version was a mess and needed to be rewired..
  Reply With Quote
Old 18th June 2008, 06:33 PM   #2523
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Quote:
Originally posted by Magura
just waste as the efficiency decreases dramatically at over 6 inches.
Something i've told all my girlfriends many times.

The Winged heatsink is actually pretty smart engineering.
__________________
The buck stops Here
  Reply With Quote
Old 18th June 2008, 06:43 PM   #2524
diyAudio Member
 
chrismercurio's Avatar
 
Join Date: Aug 2006
Location: Silicon Valley
Quote:
Originally posted by Variac
My tall tower has worked very well, but it is 6" square, and allows a lot of air flow through it- in fact more than normal because of the stack effect. A finned heatsink won't get this kind of air flow as the channels are relatively small.. Note that Nelson uses his fins horizontally, offending all purists, and they work fine. The tower gives a small footprint and like a big V8 engine, it works by having lots of inches! - about 25% more surface area than Nelson's commercial F4's. Magura predicted disaster for it and insisted on additional heatsinks, but it works fine even after I scraped the extra sinks off... I am rebuilding it for a second time and it is finally of a quality that I can live with. The show version was a mess and needed to be rewired..
I personally liked the channels hanging off the chassis. Kinda like christmas tree ornaments. They had a good pic in the AudioXpress article that covered the event.

Chris
  Reply With Quote
Old 18th June 2008, 06:50 PM   #2525
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
Yeah, but the boards kept getting moved around so various pins broke off the output devices. That's kind of sad. The repairs to the amps should have been done in a week, but I have a lot of other stuff to do like knocking member's heads together, sortin the Off Topic Pumpkin thread, etc. Also I wanted to take the time to make them something that I would feel are finished.

Certainly shorter, vertical heatsinks are more efficient- in fact I was considering
cutting some of the PAss heatsinks I got at Burning amp to use them vertically on a new project but then decided: naah! they have wide fin spacing, and I think, as I mentioned above, that increases the airflow..
  Reply With Quote
Old 18th June 2008, 07:02 PM   #2526
diyAudio Member
 
chrismercurio's Avatar
 
Join Date: Aug 2006
Location: Silicon Valley
Variac,

Do you have the AX issue with BA article? Magura wants (a scan of) it and I didn't buy the issue. I just read it at a bookstore.

Chris
  Reply With Quote
Old 18th June 2008, 07:24 PM   #2527
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 Magura



No more toys for that gentleman


Magura

I think that Papa already have 'nuff his own toys ....

__________________
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 18th June 2008, 08:25 PM   #2528
diyAudio Member
 
Join Date: Nov 2002
Location: Cologne, Germany
Ok, my PSU-trip continues...today I changed the setup of the 4-pole Jensen's and paralleled them, so that each input is in parallel and each output as well. Before, the output of one 47000uF was connected to the input of the next one, so that the current need to go through the each of them which multiplies impedance.

Some technical observations: BEfore, I have on the 24v+ 0.3mV ripple (when having them in series). Now I have 80mV ripple.

Again, No CRC, both setups have no resistor or coil/choke.

I put as well on the output of the Jensens a 0.1uF Mundorf Supreme MKP Cap (more or less inductance.free).

So, how did the sound changed ? MAybe I need to relax more, take more time. My iitial impression:

More power and basis in the bass department. IN total warmer sounding, blacker. On the down-side: Less resolution, less refined, less 3D-space. The formerly huge soundstage is now more flat, more 2D. Instruments / voices seems to be bigger.

Can that be ? What are your experiences when playing with the PSU ?
  Reply With Quote
Old 18th June 2008, 08:28 PM   #2529
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Back to the noise problem, how about just shorting the inputs
to ground right at the input jacks - no external connection, and
reporting pack on the noise?
  Reply With Quote
Old 18th June 2008, 10:41 PM   #2530
diyAudio Member
 
Join Date: Jan 2005
Location: missouri
dead quiet !!!!!!!!!!!!!bubba
  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 11:18 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