Balanced F5 in a Small Footprint - Page 2 - 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 23rd May 2012, 01:15 PM   #11
diyAudio Member
 
Join Date: Sep 2008
Wow! No laziness in you. Lots of good work. Small form factor is a great idea. Interested in the heat tunnel performance. Was there an analytical approach to determining size or was it guesswork? Target CFM, maybe?
  Reply With Quote
Old 23rd May 2012, 01:51 PM   #12
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Quote:
Originally Posted by pcb121055 View Post
Wow! No laziness in you. Lots of good work. Small form factor is a great idea. Interested in the heat tunnel performance. Was there an analytical approach to determining size or was it guesswork? Target CFM, maybe?
The size of the PCB was determined by 2 main factors:

1. The HeatsinkUSA E007 heatsink when cut in half is 7" x 5". Best MOSFET spacing becomes 3.5" x 2.5".

2. ExpressPCB offers a low cost ($85) prototype MiniBoard service for 2.5" x 3.8" boards. You get 3 custom boards for that price.

The cooling fan being used is a Noctua NF-S12B-FLX Noctua.at - sound-optimised premium components "Designed in Austria"! which can run at speeds between 600 RPM (49.2 m^3/h) and 1200 RPM (100.6 m^3/h). At 1200 RPM and 30W per MOSFET the heatsink temperature risees around 30C above ambient. I need to make additional measurements to verify the steady-state heatsink temperature vs bias current (watts) vs. fan voltage (RPM).
  Reply With Quote
Old 23rd May 2012, 01:51 PM   #13
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
did I said Fugly! ?

__________________
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 23rd May 2012, 04:02 PM   #14
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
I need to make a correction to information about the THD graphs. The bias currents were .8A, 1.2A, and 1.6A, NOT 1.0A, 1.5A, and 2.0A as previously posted.
  Reply With Quote
Old 23rd May 2012, 07:02 PM   #15
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
What's a good source for the aluminum heat tunnels?
  Reply With Quote
Old 23rd May 2012, 07:21 PM   #16
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Quote:
Originally Posted by cyclecamper View Post
What's a good source for the aluminum heat tunnels?
I use HeatsinkUSA 10.080" Wide Extruded Aluminum Heatsink cut to 7" length. 10.080" Wide Extruded Aluminum Heatsink - HeatsinkUSA, LLC Store

For the heat tunnel, the heatsink is cut in half to create 2 heatsinks 5" x 7" x 2.5". The airflow direction is 7", the heatsink width is 5" and the fin height is 2.5".
  Reply With Quote
Old 26th May 2012, 04:55 AM   #17
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Default Listening results

I have been listening to the amplifiers described above for several days. There are 4 x F5 amplifiers of 2 x F5-balanced amplifiers depending on how you make the input and output connections.

Since one PCB is composed of FQP19N20C/FQP12P20 MOSFETs and the other of FQA28N15/FQA36P15 MOSFETs, listening to the two channels in balanced stereo might be questioned. I did listen to that combo and could not find anything to fault. Likewise, I have been listening to each board as a stereo pair of ordinary (unbalanced) F5s.

Speakers: B&W CDM1

Results:

Balanced: hum and noise absolutely inaudible with ear directly at speaker cone.

Unbalanced: hum and noise barely audible with ear directly at speaker cone.

Listening to a variety of Jazz (Charlie Byrd, Miles Davie, Stan Getz, Scott Hamilton, ...) at "normal" listening levels, I could find no fault with the sound quality, and no perceptible differences between the amplifiers. Maybe someone with better ears could detect a difference, but not me.
  Reply With Quote
Old 26th May 2012, 05:07 AM   #18
lhquam is offline lhquam  United States
diyAudio Member
 
Join Date: Mar 2010
Location: Olalla, Oregon: Land of the 100 Valleys
Default Small footprint F5-Turbo

I have modified my V1.1 circult board to support the F5-Turbo diodes.

The modified board will support the following:

1. 1 x Balanced F5

2. 2 x Unbalanced F5

3. 1 x Balanced F5-Turbo-V2 with single MOSFET

4. 2 x Unbalanced F5 Turbo-V2 with single MOSFET

5. 1 x Unbalanced F5 Turbo-V1 with 2 MOSFETs

6. 1 x Unbalanced F5 Turbo-V2 with 2 MOSFETs
  Reply With Quote
Old 26th May 2012, 05:55 AM   #19
qusp is offline qusp  Australia
diyAudio Member
 
qusp's Avatar
 
Join Date: Oct 2009
Location: Brisbane, Australia
coolness! i'll keep watching the thread, i'll volunteer to test out the balanced headphone amp version, should be able to get away with passive heatsinking for that with a reasonably small heatsink
  Reply With Quote
Old 26th May 2012, 08:19 AM   #20
Banned
 
Join Date: Nov 2006
Love the heatsink and fan arrangement.
  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
small footprint speaker for kick bass BigBoned Subwoofers 12 24th October 2011 01:30 AM
Small footprint SUB using multiple small drivers FredrikC Subwoofers 5 29th August 2010 05:01 AM
Small footprint SUB using multiple small drivers FredrikC Subwoofers 0 25th August 2010 08:12 PM
First time horn help.. small footprint Matt@Nearfield Multi-Way 2 17th May 2005 02:55 PM


New To Site? Need Help?

All times are GMT. The time now is 07:24 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