Pass XA25? - Page 45 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 12th June 2017, 09:12 PM   #441
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
I have a way for first (shutting Iq of drivers and pucks) while I'm lazy to even think of mains killing

though , Papa naturally is obliged to make it foolproof , while I can't** make it (my own) proof of this fool

**(and doesn't need)
__________________
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

Last edited by Zen Mod; 12th June 2017 at 09:24 PM.
  Reply With Quote
Old 12th June 2017, 09:26 PM   #442
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
in fact , I implemented stand by in my basic iteration

hopefully it'll work
__________________
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 15th June 2017, 01:14 PM   #443
Alexiss is offline Alexiss  Sweden
diyAudio Member
 
Join Date: Sep 2003
Location: Sweden
Conceptual Schematics XXII

Well, I put together the conceptual FE and BE of the previous posts - to produce a possible iteration of the whole circuit.

I have simulated the whole circuit. Although I have not had the time to search
for the correct pspice-models of the semiconductors, it measures very well indeed with the IRFP240/9240 and the dubious models of the rest of the semiconductors.

Please take a look.
Attached Images
File Type: jpg Conceptual XA25.jpg (142.8 KB, 281 views)
  Reply With Quote
Old 15th June 2017, 01:23 PM   #444
Alexiss is offline Alexiss  Sweden
diyAudio Member
 
Join Date: Sep 2003
Location: Sweden
Comments
R30, C4, C5 are not a necessity, they bootstrap the power-feed resistors
for a slightly better PSSR and a litter higher Open-Loop Gain. They may be left out.

The circuit features very low distortion. The Square-Law characteristics of each half of the circuit
produces lower order harmonics that readily cancels out in the complementary arrangement.

The bias regulator-circuit keeps the Idc VERY stable regardless of temperature variations.
It is possible to just use a silicon-diode and a voltage divider to create the required
reference voltage.
It is not necessary to use the temp-compensated voltage reference as shown.

fft of output 20W in 8 ohms.

Bias is = 2.5 Adc
Voffset out = 1.5 mVdc
bode.jpg

fft.jpg

Last edited by Alexiss; 15th June 2017 at 01:43 PM.
  Reply With Quote
Old 16th June 2017, 02:21 PM   #445
Alexiss is offline Alexiss  Sweden
diyAudio Member
 
Join Date: Sep 2003
Location: Sweden
THD vs POWER in 8 ohms

Another interesting simulation results is the Total THD vs power into 8 ohms.

As can be seen, in spite of questionable psipce models used, the measured thd and the simulated thd vs power match pretty closely.
Attached Images
File Type: jpg thd.jpg (254.9 KB, 221 views)
  Reply With Quote
Old 16th June 2017, 05:46 PM   #446
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Probably a coincidence, given the simple models.
  Reply With Quote
Old 19th June 2017, 11:42 AM   #447
Alexiss is offline Alexiss  Sweden
diyAudio Member
 
Join Date: Sep 2003
Location: Sweden
Conceptual Schematics XXIII

For the more ambitious diy:ers, it would be possible to incorporate an additional
DC-servo for controlling the output offset voltage, eliminating the need for
adjustments.

Please look at the schematics below:
Attached Images
File Type: jpg xa25-iterations.jpg (159.0 KB, 118 views)
  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
Pass Labs amp combination for Thiel speakers, need Mr Pass' advice ! And everyone... JulienG Pass Labs 82 6th July 2015 02:41 PM
Combine high pass tweeter with mids without low pass -Need help lessNoise Multi-Way 2 3rd August 2011 10:34 AM
DIY One fader mixer with Filter Low Pass, Hi Pass, Notch Pass Filter PGM stevep314 Analog Line Level 0 10th August 2010 09:15 PM
DIY Low Pass and Mid/High Pass (Bass Blocking) Filters runslikealpaca Everything Else 1 19th June 2009 10:59 PM
My opinion on Pass Labs and Mr. Pass (Nelson) himself b_online Pass Labs 11 21st May 2003 12:39 AM


New To Site? Need Help?

All times are GMT. The time now is 03:14 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki