SMPS for chip amps - 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 20th June 2004, 11:29 AM   #1
francis is offline francis  Hong Kong
diyAudio Member
 
Join Date: May 2004
Location: HONG KONG
Question SMPS for chip amps

Hi,
I am interested to try SMPS for a LM3886 or TDA7294 amp.
Does anybody has experience on this?
Where can I obtain a dual supply SMPS?
Thanks,
Francis
  Reply With Quote
Old 21st June 2004, 02:56 PM   #2
ogurets is offline ogurets  Russian Federation
diyAudio Member
 
Join Date: Jun 2004
Location: Kazan'
for example: www.qrp4u.de/docs/en/smps_new/ ,

i made my own smps for tda7294 with ir2153 + pair irf740 + ferrite toroid 45x28x12 mm without regulation , output +- 35v without load.
in google look for sg3525 , tl494, sg3825.
IR and other IC and mosfet manufacturers have a lot of application notes on smps.
Good luck.
  Reply With Quote
Old 21st June 2004, 07:43 PM   #3
ir is offline ir  New Zealand
diyAudio Member
 
Join Date: Aug 2003
Location: WGTN, NZ
Send a message via ICQ to ir
a good friend of mine has ingeniously worked out how to derive +/-32 volts from a standard PC powersupply

benefits of this are: PC supplies are cheap or free, can provide a couple of hundred watts, and all the SMPS circuitry is already done, it just need a little tweaking

i'll provide the link to my site detailing how as soon as he finishes the writeup
  Reply With Quote
Old 21st June 2004, 08:13 PM   #4
Tim__x is offline Tim__x  Canada
diyAudio Member
 
Join Date: Jun 2004
Location: Edmonton area, Alberta
I would be very interested in that PC power supply thing.
  Reply With Quote
Old 23rd June 2004, 11:57 AM   #5
francis is offline francis  Hong Kong
diyAudio Member
 
Join Date: May 2004
Location: HONG KONG
Thumbs up Thank you!

Thanks for all replies.

I shall see if I can manage to build one.

Will update if I come up with something.

francis

  Reply With Quote
Old 23rd June 2004, 07:24 PM   #6
ir is offline ir  New Zealand
diyAudio Member
 
Join Date: Aug 2003
Location: WGTN, NZ
Send a message via ICQ to ir
i should add, the SMPS sounds brilliant.

infact, i gave him an LM4766 stereo 40W chip and he assembled the whole amp on a 1.5inch sqaure prototype board and then fit the entire thing inside the PSU. granted it has a very small heatink (maybe 2x3 inches by 1/10 thick) however thats offset by the fact it has a fan - the sound of which is easily overcome by the power of the amp

but i should also warn you, modifying a PC PSU is not entirely simple, and definitely not for beginners. it requires a lot of thought, some planning and the removal of quite a number of parts (ALL the caps on the old 3.3, 5 and 12V rails will otherwise explode for example)

but yeah, the writeup shouldn't be too far off
  Reply With Quote
Old 24th June 2004, 05:26 PM   #7
JTT is offline JTT  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: SLOUGH
Results with an SMPS may cause problems with some audio kit.

I use a Sony car radio/cd in my dining room, it's the place we live most of the time, and a car radio doesn't take up much space. This unit is the third I've used over the years, powered by a 13.5v linear supply mounted in the airing cupboard behind the kit.

However, the linear supply is getting long in the tooth, and I thought I'd replace it with a natty SMPS supply when I put in the Sony. So I used an SMPS to do the first out-of-the-box check on the new unit. ........... Oooo dear! ............ but did I get a lot of funny whistles and swishes. Fortunately, I had the sense to try it with a linear supply before rushing it back to the shop, and that showed no trouble at all.

The SMPS supply I used is the well established L30-10, a variable output professional/industrial unit, so I had a look at what it was producing on my 'scope. To be fair, it didn't look too bad. I didn't keep a record of what I saw, but I seem to remember there were switching spikes of around 100mV at 25-30KHz, and I was probably test loading it at a minimum of 2 or 3 amps. It was pretty obvious that the switching frequency was low enough too produce audible beats, although I was surprised that a unit which is expected to perform in the 'dirty' environment of a car didn't do better.

It needs to be borne in mind that switchmode supplies do not regulate to the actual output point, but sample the feed to an output LC filter, and that's all the smoothing you get. And even with a true, additional, linear output regulator, any switching spikes would probably pass straight through.

Being more optimistic, and having several SMPS around to check, it seems that current designs are more likely to have switching frequencies upwards of 50KHz - I measured one at 270KHz, so maybe the problem I encountered would be less likely if a recent unit was to be used. But it does suggest that you should try and rig up some sort of prior test, approaching what you have in mind, before commiting much time/money/effort to running an audio rig from an SMPS.

JohnT
  Reply With Quote
Old 24th June 2004, 09:39 PM   #8
solaja is offline solaja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2004
Location: srbija
Default SMPS

I was made SMPS for my vacuum tube
preamplifier.Sound is so good. My next project
will be SMPS for power amlifir.
Attached Images
File Type: jpg preamp pogled s'preda.jpg (46.9 KB, 644 views)
  Reply With Quote
Old 25th June 2004, 04:13 PM   #9
solaja is offline solaja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2004
Location: srbija
Default SMPS

Just another picture.
Attached Images
File Type: jpg ac-dc konvertor.jpg (67.6 KB, 623 views)
  Reply With Quote
Old 26th June 2004, 02:06 PM   #10
francis is offline francis  Hong Kong
diyAudio Member
 
Join Date: May 2004
Location: HONG KONG
Smile I am interested in your SMPS

Hi Solaja,

I am interested in your SMPS.

Would you mind sharing your circuit design?

Thanks and regards,

francis

  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
half bridge smps for chip amp voltage regulation question alexclaire Power Supplies 13 8th March 2008 06:39 PM
SMPS for diy audio amps and multi-channel diy amps (and their power supplies) tlparker Solid State 18 31st August 2006 10:39 AM
New Chip for smps alabpro Power Supplies 5 4th September 2005 04:56 PM
Has anyone compared the Chip amps against Class T amps? soongsc Chip Amps 3 24th July 2005 11:50 AM


New To Site? Need Help?

All times are GMT. The time now is 06:47 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