F5 power amplifier - Page 1285 - 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 January 2013, 05:39 PM   #12841
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Quote:
Originally Posted by jacco vermeulen View Post
Because Japanese manufacture for Japanese.

You are American, not Japanese, reason why it's a bit harder for you to understand.




(eer, my shorts feel like there's a third one residing within the premises, and it's a biggy)
Really, Well just who was using those JFETs in the Japanese market?
  Reply With Quote
Old 24th January 2013, 11:36 AM   #12842
slungu is offline slungu  Germany
diyAudio Member
 
Join Date: Nov 2010
Location: Germany
Quote:
Originally Posted by sangram View Post
The input FETs are not safe above 30V or so. You will need a cascode.

It will work fine if you use the cviller F5c boards and use just one output pair. Keep dissipation within the 30W target per device and you will be fine.

400VA sounds about right as a universal power supply.
Ok, I read about it in the art_f5_turbo.pdf, so basically I could go plain F5 at risk, or try a variant with cascode like the input part of V3 and maybe a higher gain while lowering the bias. That would give me more power, but it will leave Class A earlier, if I understood it correctly. Point is I don't want a monster heatsink that would be required in order to go up in Class A power, so I would sacrifice that for more power in the cases when it's needed.

Regards, Stefan
  Reply With Quote
Old 24th January 2013, 12:08 PM   #12843
udailey is offline udailey  United States
diyAudio Member
 
Join Date: Mar 2008
How about a small fan plus small-ish heatsink?
__________________
purchase LDRs anytime Also try my Resistor Replacers or LDR based Input Selector Email me. diyldr@gmail.com
  Reply With Quote
Old 24th January 2013, 12:35 PM   #12844
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 labjr View Post
Really, Well just who was using those JFETs in the Japanese market?
The answer would be shorter had you asked who wasn't.

The Japanese industry is highly interlinked, both through tradition and long term contracts (which often also have historic links).
On top of that there are huge conglomerates in Japan.
Take e.g. the Mitsubishi corp., everything from banking & insurance, to consumer electronics and parts, to cars and building oil tankers(MHI).

Suppose Toshiba transistors developes a part for Toshiba consumer electronics.
After an average manufacture span of 20 years, Toshiba transistors will develop a successor part, and the old one goes obsolete.
If Toshiba consumer electronics has no need for a successor part, the old one goes obsolete and no replacement.
Even if production of the old part may still be profitable for the foreign market, Toshiba will halt manufacture.

A US company also primarily developes a product for the local market, say Motorola.
It will also start selling abroad once the local market has reached maturity.
The American company will continue manufacturing till total volume of both domestic and foreign demand has dropped to a level that's not worth the effort.

In Japan, the communication path between JFET manufacturer and JFET end user is short, and highly interactive, within a conglomerate as well as between e.g. Toshiba and Sony.
They make both The part for A market, and vice versa, but not just A part for A market.

The JFET numbers have been available in the west for quite a long time.
I can give you plenty examples of Japanese devices that were barely available abroad, with room for growth, when manufacture was terminated.
__________________
The buck stops Here
  Reply With Quote
Old 24th January 2013, 01:52 PM   #12845
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
and you , cheapskate , have them all .......

__________________
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 24th January 2013, 07:26 PM   #12846
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
There is too much concern about these particular Jfets for the front end
of the amplifier. Yes, the 2SJ74 and 2SK170 are really superb, particularly
on the noise front, but this is not as important when we are already dealing
with line level volts instead of millivolts.

You can still get the Fairchild J174, J175, P1086 P channel devices from such
places as Digikey and Mouser, and they are cheap.

The N channel are even easier to get, such as the Fairchild J111. Worst
case you might have to parallel two, but even that is unlikely. You might
have to select them, but at prices like $0.11 for quantities, you can hardly complain.

Better buy them before I do....

  Reply With Quote
Old 24th January 2013, 07:38 PM   #12847
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
I had thought there were no parts which could match the performance of the 2SJ74 and 2SK170? I mean we don't want close performance. We want equal or better.
  Reply With Quote
Old 24th January 2013, 11:05 PM   #12848
Renron is offline Renron  United States
diyAudio Member
 
Renron's Avatar
 
Join Date: Jan 2007
Location: Sacramento
Quote:
Originally Posted by Nelson Pass View Post

Better buy them before I do....

ROFLMAO
__________________
"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 25th January 2013, 12:01 AM   #12849
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
Quote:
Originally Posted by Nelson Pass View Post
You can still get the Fairchild J174, J175, P1086 P channel devices from such places as Digikey and Mouser, and they are cheap.

The N channel are even easier to get, such as the Fairchild J111. You might
have to select them,
but at prices like $0.11 for quantities, you can hardly complain.
If selecting, we should be aiming for an Idss of 8-10 or so?
  Reply With Quote
Old 25th January 2013, 12:11 AM   #12850
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Don't seem like there's many left. We're like a bunch of crackheads.
  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 11:45 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