regulated power supply for high powered amps. - 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 3rd March 2009, 02:31 PM   #1
diyAudio Member
 
Join Date: Nov 2007
Default regulated power supply for high powered amps.

Hi,

Before this site closes for renovation, I wish to ask if you know a circuit for a fully regulated power supply that could output more or less about +/- 70V and 10ampere.

I also would like to ask if it is worth the effort if I use fully regulated power supply for 200W per channel amps.?

Thanks in advance.
  Reply With Quote
Old 3rd March 2009, 04:13 PM   #2
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
You can go for the LT1083 regulator IC; guaranteed 7A, typical 10A output current.

As it is a low-dropout chip, power dissipation stays reasonable. However don't forget that if you really want to exploit it fully you need to handle ripple before the reg and toroid regulation as well.

Have fun, Hannes

PS: some more details:

Interest in dual regulator LT1083 pcbs?
  Reply With Quote
Old 3rd March 2009, 04:26 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
200W and +-70Vdc supplies sounds like you intend to drive 8ohm speakers.

Maximum output to the speakers will be ~56Vpk, you might get 60Vpk or slightly more on short transients.

Peak current in to an 8r0 resistor will be 7Apk.
Peak current into an 8ohms speaker could be around 20Apk and severe reactance speakers could demand peaks even higher than this on fast starting/stopping transients.

If the supply is rated to 10A, where will the extra current come from to drive the speaker?
__________________
regards Andrew T.
  Reply With Quote
Old 3rd March 2009, 10:46 PM   #4
diyAudio Member
 
Join Date: Nov 2007
Andrew and Hannes, Thanks to both of you.

@Andrew,

Will adding capacitors after the regulator enough to take care of the peak demands of the amp.?

@ Hannes,

If I build parallels of the circuit you posted , How many of it in parallel do you think is able meet or exceed the demand, of a single 200W@8ohms amps driving a 4ohms load full blast in a home environment?

Thanks.
  Reply With Quote
Old 4th March 2009, 08:06 AM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally posted by marchel
Will adding capacitors after the regulator enough to take care of the peak demands of the amp?
yes, but you will then be running the amp off the caps and throwing away most of the advantage of the regulation.
__________________
regards Andrew T.
  Reply With Quote
Old 4th March 2009, 08:17 AM   #6
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Quote:
Originally posted by marchel
If I build parallels of the circuit you posted , How many of it in parallel do you think is able meet or exceed the demand, of a single 200W@8ohms amps driving a 4ohms load full blast in a home environment?



I may be missing something but how are these parallel regulators going to meet your voltage requirements?

If you look at a practical implementation which still falls short of your requirements, like the Naim NAP250, you will notice that the regulator is similar in complexity, parts count and power dissipation to the amp.

It may be arguable if the increased cost and complexity are not better justified by building a better amp.
  Reply With Quote
Old 4th March 2009, 08:58 AM   #7
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally posted by analog_sa




I may be missing something but how are these parallel regulators going to meet your voltage requirements?

If you look at a practical implementation which still falls short of your requirements, like the Naim NAP250, you will notice that the regulator is similar in complexity, parts count and power dissipation to the amp.

It may be arguable if the increased cost and complexity are not better justified by building a better amp.

No, you did'nt miss anything , But I did.

I did a further reading about it and it turned out it does not meet the voltage requirement, It seems to me that discrete design is the way to go.

I also did a reading about using regulated power supply for hi power amps, And it turned out that it would be very impractical an very expensive if the amps is to rated to drive lower impedance with reasonable safety margin on the regulator. And aside from that there is also some sonical disadvantages of regulated power supply for ampli application, I dont think I want to go that way anymore.

However, There is something to be gained by using separate regulated power supply for the input and drive stages. Does anyone here know a schematics for low amperage 70-0-70V regulator?

Thanks.
  Reply With Quote
Old 4th March 2009, 10:30 AM   #8
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Hi marchel,

you're not a close reader, are you

Quote:
I did a further reading about it and it turned out it does not meet the voltage requirement
The LT1083 does meet your requirement, it's all about voltage differential. And you're right, it's an expensive chip. However caps cost money as well.

Wether regulated power supply hurt sonics or not is your personal preference. With a little care to details both can give excellent results. As you find out by googling easily, there are classic amps with and without regulated output stages with high reputation.

For your frontend you can use the lm3x7 series regulators, they're regularly used in commercial stuff (when the high end manufacturers once do not use 7x15 regulators ). You find an exemplary schematic in the datasheet as well.

If you want to go complex, there are lots of discrete regulators as well, however to get their real performance you need to have a little more knowledge.

Have fun, Hannes

EDIT: oh and please take a lot of care working on a +-70V amp; these rails can really hurt.
  Reply With Quote
Old 4th March 2009, 12:45 PM   #9
diyAudio Member
 
Join Date: Nov 2007
Hi Hannes,

Your right , I'm not a close reader, I misinterpreted the current limit over voltage diffrence on the datasheet as the absolute limit of the operating voltage regulator IC itself.

I'm more of a speaker and passive preamp DIYer than electronics, SO I'm not so well versed in this area. Nobody's perfect

Regarding the schematics you posted on the link you've given, If I were to use it on a power amp that have + and - rail, I noticed that the lower regulator's input and output is connected to the 0V or ground .

Questions:

Does this mean I can't use a transformer with center tapped secondary, Where the center tap is connected to ground?

Will the circuit necessitate the use of separate windings or 2 separate transformer for each (+and-) rail?
  Reply With Quote
Old 4th March 2009, 01:12 PM   #10
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Sofia
Quote:
Originally posted by h_a
Hi marchel,

you're not a close reader, are you



Apparently nor am i

Curious though: can it really output hundreds of volts if the differential limit is met?
  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
Lost Thread-High VOltage Regulated Power Supply LinuksGuru Tubes / Valves 2 21st June 2009 01:48 AM
Links to High Current Regulated Power Supply? lgreen Solid State 1 25th January 2005 12:11 AM
high performance regulated supplies for power amps jez Solid State 14 5th January 2004 03:22 PM
high-voltage regulated dual power supply zzz Solid State 1 17th September 2002 01:15 AM


New To Site? Need Help?

All times are GMT. The time now is 12:24 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