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 September 2012, 02:35 PM   #411
Rush is offline Rush  United States
diyAudio Member
 
Join Date: Sep 2009
Location: Tampa, Florida
Quote:
Originally Posted by buzzforb View Post
All this assumes that you dont think that a 200W amp sounds better than a 50W amp driving the a set of 90dB speakers.
I do think a 200W amp sounds better than a 50W amp pushing a 90db speaker, not because of the watts, because of the power supply and number of output devises. So if we build our 50W amp with the current capability of a larger amp, not the higher voltage rails, then they should sound the same given all else equal, IMHO.

Rush
  Reply With Quote
Old 16th September 2012, 03:29 PM   #412
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Then why not go with V3, biasing the outputs at .5A across 1ohm Rs. You get more devices, higher DF, more stable temps on individual fets. Basically choices made by Nelson in XA.5 series. Or go V3 on dual monoblocks, maintaining 1A bias and gaining in all other respects. PSU is simple and size is matter of choice. Nelson does 90mF per rail, I believe. Beauty of F5T is scalability. Simple amp with very simple path to more power. You probably have a very good idea of what to do based on out conversations. FWIW, I do believe the 2 pair F5T sounds better than the F5.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 16th September 2012, 03:34 PM   #413
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Anybody who can help with this question?

In mating two larger heat sink together to form one larger sink, which would be a better implementation for heat dissipation?

Heatsinks being used will be 10.08 version from Heatsink USA. I have two options for heatspreader. One is large piece of L aluminum with 2" flange that is 1" thick and a 4" flange that is 1/2" thick. The 1/2" thick section would be tied to the heatsinks and the overall length would be about 12-14" on a heatsink that is about 18" long after being cut down.

The other option is a big piece of 2" thick aluminum 4" x 12-14".

What do you think?
__________________
...Shape the sound , Man!
  Reply With Quote
Old 16th September 2012, 03:42 PM   #414
diyAudio Member
 
Join Date: Feb 2009
the 4" will be the best
  Reply With Quote
Old 16th September 2012, 03:51 PM   #415
Rush is offline Rush  United States
diyAudio Member
 
Join Date: Sep 2009
Location: Tampa, Florida
Quote:
Originally Posted by buzzforb View Post
Then why not go with V3, biasing the outputs at .5A across 1ohm Rs. You get more devices, higher DF, more stable temps on individual fets. Basically choices made by Nelson in XA.5 series. Or go V3 on dual monoblocks, maintaining 1A bias and gaining in all other respects. PSU is simple and size is matter of choice. Nelson does 90mF per rail, I believe. Beauty of F5T is scalability. Simple amp with very simple path to more power. You probably have a very good idea of what to do based on out conversations. FWIW, I do believe the 2 pair F5T sounds better than the F5.
The reason why would be, number of devises per channel (I bought the V2 boards and am committed to stereo amps) and Rs of 1 ohm. I am thinking Rs should be the lowest you can get away with. Also I am old and the weight of working on and moving a V3 is more than I am willing to bare. Compromises everywhere.

Rush
  Reply With Quote
Old 16th September 2012, 04:03 PM   #416
Rush is offline Rush  United States
diyAudio Member
 
Join Date: Sep 2009
Location: Tampa, Florida
Quote:
Originally Posted by buzzforb View Post
Anybody who can help with this question?

In mating two larger heat sink together to form one larger sink, which would be a better implementation for heat dissipation?

Heatsinks being used will be 10.08 version from Heatsink USA. I have two options for heatspreader. One is large piece of L aluminum with 2" flange that is 1" thick and a 4" flange that is 1/2" thick. The 1/2" thick section would be tied to the heatsinks and the overall length would be about 12-14" on a heatsink that is about 18" long after being cut down.

The other option is a big piece of 2" thick aluminum 4" x 12-14".

What do you think?
I'll bet you can get the heatsinks welded together for less than $100. The issues would be smoothing the welded area. A surface grinder would be nice, but a large file and a DA sander with 60/120/240 grit sand paper would do it. Or you could notch your heat spreader at the joint if it remained proud.
I say this, with the same problem and I have not done this. I even own a mig welder with aluminum capability (and a DA). We should ask Heatsink USA what aluminum they used, so the proper weld rod can be chosen.

Rush
  Reply With Quote
Old 16th September 2012, 05:00 PM   #417
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Quote:
Originally Posted by AudioSan View Post
the 4" will be the best
meaning the 4" thick flat bar?


Quote:
Originally Posted by Rush View Post
The reason why would be, number of devises per channel (I bought the V2 boards and am committed to stereo amps) and Rs of 1 ohm. I am thinking Rs should be the lowest you can get away with. Also I am old and the weight of working on and moving a V3 is more than I am willing to bare. Compromises everywhere.

Rush
I agree all around. Drop the diodes, use 4 fets, bias each at .5A or more, and use .22R resistor.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 16th September 2012, 05:03 PM   #418
diyAudio Member
 
Join Date: Feb 2009
the 4" wide 1/2" thick will do the job.
  Reply With Quote
Old 16th September 2012, 06:57 PM   #419
a.wayne is offline a.wayne  United States
diyAudio Member
 
a.wayne's Avatar
 
Join Date: May 2008
Location: Front Row Center
I would agree with this assumption ....

Quote:
Originally Posted by Rush View Post
I do think a 200W amp sounds better than a 50W amp pushing a 90db speaker, not because of the watts, because of the power supply and number of output devises. So if we build our 50W amp with the current capability of a larger amp, not the higher voltage rails, then they should sound the same given all else equal, IMHO.

Rush
  Reply With Quote
Old 23rd September 2012, 02:05 AM   #420
anilva is offline anilva  India
diyAudio Member
 
Join Date: Mar 2004
Location: Bangalore
Default Regarding heatsinking for Switching diodes

I have asked a question earlier on heatsinking of the switching diodes MUR 3020WT at the outputs of F5T V2.

I did get a reply of keeping the heatsink separate from the heatsink of the output devices. OK. Can I run a simple aluminium flat tying the 8 MURs on each side as a heatsink. How much heat should I expect? I am using Teabag's boards.

TIA.
__________________
DIY F5 Turbo V3, DIY F5 Turbo V2, DIY F5, DIY F5 Toshiba Dual output, DIY Aleph J, DIY Fostex 206 BLH, DIY Altec Onken with 515B LF & 288H HF, Behringer Digital Xover, Technics SP10 MKII & SL-1210, EMT938 TT.
  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
F5 Turbo is posted Nelson Pass Pass Labs 635 6th April 2014 10:51 AM
B1 builders thread Bas Horneman Pass Labs 694 25th February 2014 06:29 PM
F5 Turbo Circuit Boards chchyong89 Pass Labs 2327 8th January 2014 02:14 PM
F5 turbo problems Rob Dingen Pass Labs 17 11th January 2013 08:38 PM
F5 Turbo ............. if only !!!!!! a.wayne Pass Labs 23 21st January 2012 02:24 AM


New To Site? Need Help?

All times are GMT. The time now is 09:57 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