F5 power amplifier - Page 99 - 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 1st June 2008, 12:29 AM   #981
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default Re: Re: re: f5 PCB

Quote:
Originally posted by juma



Read my mail again
It's 9.9 cm x 3.5 cm (1" = 2,54 cm)
I'll print it into Photoshop CS2, and do a PDF at 100%, but you'll probably have to get rid of the jaggy's from going to BMP. I'll post a PDF here.
  Reply With Quote
Old 1st June 2008, 01:21 AM   #982
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Here's the PDF to scale, but PM me for a PDF of the BMP which has no gray-scale.
Attached Files
File Type: pdf f5_pcb.pdf (11.1 KB, 860 views)
  Reply With Quote
Old 1st June 2008, 01:30 AM   #983
diyAudio Member
 
Join Date: Nov 2006
One dead bug channel of F5 is up and running.

Not having the correct devices on hand, I had to use some old junk-fets I had laying around, in this case a 2n4416A and a 2n5116. They had Idss's of 9ma and 12ma, closest match to the recommended I had on hand.

A 10khz square wave shows no overshoot, and looks very square.

Yes, that is speaker wire you see attached. After letting it warm up for about 40 minutes, it seemed very stable, so I hooked it up to a speaker and listened to one channel of Dido.

First impression was that the F5 does an amazing job of reproducing every aspect of her voice -- which is simply amazing.
Very detailed amp-I can't wait to do the other channel. (even though it is surely nowhere near one built with the right j-fets)

JJ
Attached Images
File Type: jpg 024 small.jpg (32.9 KB, 2568 views)
  Reply With Quote
Old 1st June 2008, 02:48 AM   #984
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Too late to take a picture, and I want to sit down with the XYL and watch some TV (it's almost 11 p.m. here in the People's Republic of New Jersey), but using separate gate input resistors has had a most salutory effect.
  Reply With Quote
Old 1st June 2008, 03:06 PM   #985
Tea-Bag is offline Tea-Bag  United States
not politcally affiliated
diyAudio Member
 
Tea-Bag's Avatar
 
Join Date: Feb 2006
Location: Kennebunk
Blog Entries: 7
Default F5 PCB

Jack, Thanks for shinking this.
Jumo, thanks for doing the layout work.
  Reply With Quote
Old 1st June 2008, 05:21 PM   #986
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by jupiterjune
Not having the correct devices on hand, I had to use some old junk-fets I had laying around, in this case a 2n4416A and a 2n5116. They had Idss's of 9ma and 12ma, closest match to the recommended I had on hand.

A 10khz square wave shows no overshoot, and looks very square.

...(even though it is surely nowhere near one built with the right j-fets)
That the ticket. I'm sure that those JFETs work fine although they
do look to have a lower transconductance than the 2SK170/2SJ74.
  Reply With Quote
Old 1st June 2008, 07:11 PM   #987
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
While your article describes the basic circuit brilliantly in layman terms, it contains little details on how it is designed for stability given the high bandwidth. After so many informative articles on the Zen series plus other First Watt designs, perhaps you could shred some light on how you go about designing for frequency related performances ?? And I guess F5 would make a great example for that purpose, specially in the light of the difference in peformance as measured by jackinnj than your own .....


Looking forward to your enlightenment,
Patrick
  Reply With Quote
Old 1st June 2008, 08:01 PM   #988
jam is offline jam  United States
diyAudio Member
 
jam's Avatar
 
Join Date: May 2001
Location: Auburn, CA, USA
..............enlightenment.

http://www.do-not-zzz.com/

Jam

Sorry! I could not resist.
  Reply With Quote
Old 1st June 2008, 09:24 PM   #989
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by EUVL
And I guess F5 would make a great example for that purpose, specially in the light of the difference in peformance as measured by jackinnj than your own .....
Why don't we start with his results?
  Reply With Quote
Old 1st June 2008, 10:29 PM   #990
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> Why don't we start with his results?

Sure.

To achieve decent square waves at 100kHz as shown in your article, one would guess that one might want to get the closed loop bandwidth at something like 1MHz plus. As he showed in his measurements, the frontend, with its low impedance gate and source impedances, would probably have a corner frequency beyond that. Thus, it is probable that the first RC dip in open loop comes from the 600 ohm drain resistor and the input capacitance of the MOSFET. If this is far enough apart from the corner frequency of the input stage, then we should not get 180 deg phase shift when closing the loop. Correct ? One would guess that f1/f2 wants to be larger than the amount of negative feedback (say > 35dB).

However, the F5 is essentially two amplifiers mirrored about ground, and the frequency response of each half is different. So I guess this explains why there are more than 1 peak in the frequency response. I have not worked out all the RC values yet (if I remember correctly, the MOSFET gate has a corner frequency of something like 30-40 kHz), but assuming the same devices, I wonder why he is getting such different response than you did ??


Patrick
  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 10:28 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