NEED HELP for Pioneer A400x mods - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 31st July 2007, 10:24 AM   #1
diyAudio Member
 
Join Date: Jul 2007
Question NEED HELP for Pioneer A400x mods

NEED HELP for Pioneer A400x mods
Hi every one, I am new to this forum, I am working on a A400x at the moment.
For the dc coupling I used WAMA 3.3uF MKS4 non-polar. On power supply, i used a high speed rectifier bridge and 0.1uF WAMA bypass on every filter caps. I also added few 100uF/50V Panasonic FC and WAMA MKF on V+/V- of each transistor.
After the mods, rectifier replacement improved the quality of the bass a bit, WAMA give very nice high end, however the whole image became too bright.

Is there anyone have experienced on mods A 400 or A 400x?
Q1: how can I avoid the sound become too bright?
Q2: how can I get better bass control?
Q3: if I increase the bias current, does the 2SA/2SK driving pair needs a heat sink?
Q5: A400 originally 20mA on each power transistors, I am going to boost up to 100mA. Would that give me a warmer sound and better bass control?

Thanks very much!!!!!!!!!!!!!!!!!!
  Reply With Quote
Old 31st July 2007, 12:33 PM   #2
rabbitz is offline rabbitz  Australia
diyAudio Member
 
rabbitz's Avatar
 
Join Date: Jul 2003
Location: Newcastle, Australia
Did a few small mods on my A400X.

Input caps changed to 4.7uF Nichicon ES and maybe Black Gate N or NX would work well here.

The main power supply caps were changed to 10000uF Nichicon Gold Tune.

Caps for op amp were changed to 100uF Nichicon Fine Gold. Tried a few different op amps such as OPA2134, 5532, AD826 but the original M5220 sounded the best. The other op amps may have needed some different power and by-pass caps but wasn't worth playing with.

The mods have seemed to give a bit more drive all round and more control in the bottom.... deeper may be?? ... a tad more clarity but no other noticeable changes. For the few dollars, was worth it.
  Reply With Quote
Old 1st August 2007, 08:12 AM   #3
zanash is offline zanash  United Kingdom
diyAudio Member
 
Join Date: Feb 2005
Location: Notts
I suspect your dc decoupling caps are the issue ....try doubling them up to get 6-10uf ...or try a different cap..

I don't have the schems so can't offer any more advice.
  Reply With Quote
Old 1st August 2007, 02:58 PM   #4
diyAudio Member
 
Join Date: Jul 2007
Default thanks every one!

Hi, thanks for the replys. here is the link to A400 and A400x manual: http://www.hifiengine.com/manuals_ty...oneer&mod=A400
  Reply With Quote
Old 21st January 2009, 04:57 AM   #5
diyAudio Member
 
Join Date: Oct 2007
Location: Melbourne
Hey Rabbitz, where did you source the Nichicon Gold Tune caps in Australia?
Many thanks, Richard.
  Reply With Quote
Old 21st January 2009, 02:02 PM   #6
rabbitz is offline rabbitz  Australia
diyAudio Member
 
rabbitz's Avatar
 
Join Date: Jul 2003
Location: Newcastle, Australia
Had to get them from Canada.

http://www.minisemi.com/Nichicon%20M...apacitors.html
__________________
No longer DIY active
  Reply With Quote
Old 21st January 2009, 10:41 PM   #7
diyAudio Member
 
Join Date: Oct 2007
Location: Melbourne
Thanks for the info
Cheers,
Richard.
  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
Pioneer A400X help. How to uninstall the input switch? Huchiz Solid State 16 21st September 2008 12:33 PM
Pioneer PD-S06 mods - some experience? Alfetta87 Digital Source 0 8th August 2006 02:55 PM
Pioneer PD-65 Schem & Mods richardau Digital Source 14 4th September 2005 05:11 AM
Pioneer DVD-656 Mods kenlow Digital Source 2 14th January 2004 12:41 PM
Sowter/Pioneer AX-10 Mods rljones Digital Source 21 30th December 2002 07:43 AM


New To Site? Need Help?

All times are GMT. The time now is 09:15 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