Dual Mono vs Stereo Power Supply Question - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 2nd January 2007, 01:55 PM   #1
bluegti is offline bluegti  United States
diyAudio Member
 
Join Date: Nov 2004
Location: Northern Virginia
Default Dual Mono vs Stereo Power Supply Question

I bought the LM3886 Dual Mono Kit from Brian at chipamp.com. I probably should have asked more questions before I bought...

The kit comes with 2 Power Supply Boards. I don't really want to build 2 monoblock amplifiers. I want to have stereo amp in a single chassis.

Is there any reason to use a separate power supply board for each channel in a single chassis?

If I do use a separate power supply board, do I need two transformers or can I still use one with dual secondaries?

Still learning. Thanks.
  Reply With Quote
Old 2nd January 2007, 02:17 PM   #2
diyAudio Member
 
Join Date: Feb 2006
Location: Atlanta
You may or may not notice any difference.

By using two isolated transformers, there is almost no way the load from one channel will impact the other. With a single unit, there is always a possibility of interaction and therefore a negative sound experience.

If the dual secondary unit is well above minimum specifications for the two amp blocks then you may not have any issues. Let's face it... your average SONY AMP has a single supply dual secondary transformer.

Be very aware of how you connect your common grounds.
__________________
pw
  Reply With Quote
Old 2nd January 2007, 02:39 PM   #3
phn is offline phn  Sweden
diyAudio Member
 
phn's Avatar
 
Join Date: Oct 2004
http://www.stereophile.com/solidpowe...47/index4.html

I have posted this link here before.

I second pwillard. But would like to add that the Gaincard seems to have a poor PSU. 170W, or 85Wpc, should be enough for a 2x25W amp.
  Reply With Quote
Old 2nd January 2007, 03:00 PM   #4
diyAudio Member
 
ianpengelly's Avatar
 
Join Date: Oct 2006
Hi Bluegti,

I have built the same amp kit into a single chassis using 1 transformer (300VA) and it works like a charm. I used a couple of connectors to share the pair of secondary windings between the rectifier board. You can see it here:

Yet another 3886 gain clone!

There are pleanty of people that have done the same if you look at the pictures posted on the chipamp.com site.

Hope this helps!

Ian
  Reply With Quote
Old 2nd January 2007, 03:26 PM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
a single transformer with dual secondaries will work a charm driving two amplifying channels, but, you must use two separate PSUs (rectifier + dual smoothing caps) each dedicated to it's own amp channel.

There is a problem with the chipamp PCB. Most chipamps combine the signal ground and power ground. When combining these into a two channel amp you end up with a ground loop through the two inputs.

I have not researched a solution (I don't use chipamps) but some have found that mounting the chip amps VERY close together and linking the audio grounds with a very short and thick wire, then running the midpoint of this common ground wire to the PSU 0volt common and speaker return and Zobel return and to disconnecting network will provide a partial solution that results in almost inaudible hum. A bit of experimentation here will require all the extra off board grounds to be bolted earth tags until you find the quietest arrangement.

An alternative is to build two truly isolated channels inside the stereo case and use a four secondary transformer, but these are expensive or difficult to source.

The transformer VA~=1.5times the total power from the two channels.
__________________
regards Andrew T.
  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
Dual-Mono vs Stereo, which set is better for the ambitious first time builder? blacksquirrel Chip Amps 1 7th July 2008 03:13 PM
Dual mono power supply's for the zappulse micheat Class D 3 4th November 2004 06:46 AM
Dual Mono v. Stereo Papageoff Chip Amps 5 2nd November 2004 08:50 PM
dual mono vs stereo audioPT Solid State 6 26th October 2003 07:10 PM


New To Site? Need Help?

All times are GMT. The time now is 07:02 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