Go Back   Home > Forums > >

Pass Labs This forum is dedicated to Pass Labs discussion.

F3X
F3X
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
Old 24th November 2020, 09:22 PM   #1
woofertester is online now woofertester  United States
diyAudio Member
 
Join Date: Jun 2011
Default F3X

Has the notion of an F3X ever been discussed? I searched and did not find anything. The application would be direct drive of electrostatic headphones or even full-size ESL panels.
  Reply With Quote
Old 24th November 2020, 09:36 PM   #2
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F3X
have none of these, so - it didn't crossed my mind
__________________
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 November 2020, 10:38 PM   #3
woofertester is online now woofertester  United States
diyAudio Member
 
Join Date: Jun 2011
Quote:
Originally Posted by Zen Mod View Post
have none of these, so - it didn't crossed my mind
The first electrostatic speaker I listened to was at a co-worker's house. It was Acoustat model X which had a direct drive tube amplifier. The sound was very different from any other speaker and in a good way. The speakers are push-pull and the THD is on the order of 10X lower than voice coil magnet speakers.

That led me to build a pair of Roger Sanders DIY ESLs in the 1980s. They were driven using a pair of UTC tube transformers that I still have. I always wanted to listen to ELSs with a direct drive amp.

Now I have Stax Lambda and Stax Gamma ESL headphones with a Stax SRM-313 direct drive amp. It uses Toshiba JFET inputs a-la Pass but all the rest is garden variety BJTs which I would like to transform into SIT driven output stage a-la Pass F3.

The DC rails on the Stsx amp are + / - 300V and the bias on the diaphragms is something like 240V.

I think an F3 based design can be DC coupled for this application.
  Reply With Quote
Old 24th November 2020, 10:46 PM   #4
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F3X
it looks easy on paper (hell of a cascoding, plus converting a core to LTP, should solve most of puzzle) but certainly needing decent polishing time

so, lemme pass that one, no need to be wise-a$$ if I'm not planning to invest bench time
__________________
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 25th November 2020, 12:16 AM   #5
zchopper is offline zchopper
diyAudio Member
 
Join Date: Apr 2016
F3X
Default umm . . .

Quote:
Originally Posted by Tea-Bag View Post
For those who have been hording LU's or waiting for a balanced F3 amp, ZM proposed the following.
That was followed by what I am convinced is easily the single greatest perpetration of diyaudio in history.

donut-a-la-overkill

Called the Choky Susy F3 or Donut a'la Overkill

There is a pic in one of the threads where they were pouring the case at the foundry. Epic. Attached is one pic I keep and look at when I need inspiration.
Attached Images
File Type: jpg post-18-124854439628.jpg (35.4 KB, 166 views)

Last edited by zchopper; 25th November 2020 at 12:32 AM.
  Reply With Quote
Old 25th November 2020, 10:03 AM   #6
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F3X
yup Kwayzee Danske MetalKid - Magura

later resorted to games making money

schematic was result of his insisting on concept and me making patches

these days I'll do it differently, most likely
__________________
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 25th November 2020, 11:12 AM   #7
Gyuri is offline Gyuri  Hungary
diyAudio Member
 
Gyuri's Avatar
 
Join Date: Nov 2003
Location: Budapest
It isn't X-ed, only bridged:

So, this is my Quad ZV9!

Once upon a time, I have listened it with Focal Jmlab Vega speakers, sound was comparable to a factory Pass XA30.5.
Of course that was better.
But I was not ashamed of my amp.
__________________
Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat
  Reply With Quote
Old 25th November 2020, 01:38 PM   #8
woofertester is online now woofertester  United States
diyAudio Member
 
Join Date: Jun 2011
Quote:
Originally Posted by Gyuri View Post
It isn't X-ed, only bridged:

So, this is my Quad ZV9!

Once upon a time, I have listened it with Focal Jmlab Vega speakers, sound was comparable to a factory Pass XA30.5.
Of course that was better.
But I was not ashamed of my amp.
Congrats on a very nice amplifier build.
  Reply to this post

Reply


F3XHide this!Advertise here!
Thread Tools

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

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 06:22 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki