Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Bypassing DVD amp
Bypassing DVD amp
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
Thread Tools Search this Thread
Old 23rd August 2004, 03:15 PM   #1
Triox is offline Triox  Australia
diyAudio Member
Join Date: Jul 2004
Location: Australia
Default Bypassing DVD amp

The amplifiers in my Digitrex DVD player which are LM4731,s have been destroyed. These don,t seem to be available in Australia.

These are National 25W /25W.

To cut a long story short , I removed the amplifier chips and heatsinks , put extra sockets on the back of the unit and attached these to what were the inputs of the LM4731.
These inputs are fed by a 1 uF cap and a 1K resistor in series.

I have hooked these new outputs to an external amplifier and all seems well.

Does anyone see any potential problem with this and maybe offer some tips.

I have built some Digi 125s , but am not overly impressed with the sound volume, as my old 35W amplifier seems louder and clearer.

I will probably build some P3A amps or similar and attach
these new outputs to the amp inputs.

My only problem now is I need 6 amps to cover the 5:1 outputs.

I wonder if it,s worthwhile to spend so much buying ready made PCB,s?

ALso do you think I,ll need a pre amp?
  Reply With Quote
Old 25th August 2004, 02:33 PM   #2
Triox is offline Triox  Australia
diyAudio Member
Join Date: Jul 2004
Location: Australia
Default Re DVD player with built in amplifier.

I tried a 741 pre amplifier to drive the digi 125 from my dvd and
it sounds a lot louder, but its a bit noisy, seems to pick up hums and buzzes ,

Any ideas how to make a simple quiet pre-amp?
  Reply With Quote
Old 25th August 2004, 05:06 PM   #3
jaycee is offline jaycee  United Kingdom
diyAudio Member
Join Date: Apr 2004
Location: Norwich, UK
You will probably need a buffer preamp stage because I would guess that the 4731's were being directly driven by the output from the DAC stage.

Do not use the 741 op-amp for audio. It is awful. If you want it simple, build one around an 5532. Elliot's P88 will do if you are into his designs.
  Reply With Quote


Bypassing DVD ampHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bypassing the LM6171 Fat Dave Chip Amps 21 5th March 2016 11:32 AM
Bypassing B+ in PP amp lcsaszar Tubes / Valves 6 5th May 2008 09:28 PM
Bypassing Lostcause Parts 8 23rd August 2006 08:24 AM
Why bypassing this way? StefanJ83 Parts 4 30th January 2002 11:38 PM
PS bypassing in BOZ pjkunz Pass Labs 1 17th November 2001 01:40 PM

New To Site? Need Help?

All times are GMT. The time now is 10:12 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio