opa541 schematic - Page 2 - 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 29th November 2006, 01:58 AM   #11
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
No, the Va rateing is different than watts...I believe they get the VA Rateing by multiplying the Voltage with the Amps to get the Va rateing....

Also that isn"t a Power supply that is just a Transformer you will still need a bridge rectifier or a Diode Bridge and about 10,000uF of Caps (Per Rail?) and some resistors to make a workable Power supply.....

also a 2x28v Transformer will give you about 40v+ after rectification which might be a bit high for a chipamp, Maybe 2x24v would be better to give you closer to 35v.....


Cheers
  Reply With Quote
Old 29th November 2006, 02:06 AM   #12
s_pics is offline s_pics  Canada
diyAudio Member
 
Join Date: Nov 2006
I though that it was 28V divided by square root 2 ( 28/0.707) so 19.8 V.

not 28V time sqareroot2 (28*1.41)

I'll need to check for that
  Reply With Quote
Old 29th November 2006, 02:25 AM   #13
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
No, That transformer is a 2x28v Transformer so it has two 28v AC windings which when converted to DC will be in the neighbourhood of 2x40v DC.....

If the Transformer was a 28v Center Tapped Transformer then it could be interperated as 14v ,0v ,14v Transformer but that is not they type of transformer you posted in your Link.....


You want a Transformer with Dual secondaries or Center tapped but at 28v AC the Voltage will be a Bit high unless you regulate it down a Bit.....


Cheers
  Reply With Quote
Old 29th November 2006, 03:08 AM   #14
s_pics is offline s_pics  Canada
diyAudio Member
 
Join Date: Nov 2006
thanks so that is not a good transfo for me cause it is not center tap so I can't get negative tension

appreciated
  Reply With Quote
Old 29th November 2006, 03:18 AM   #15
Duo is offline Duo  Canada
diyAudio Member
 
Duo's Avatar
 
Join Date: Jun 2002
Location: Victoria, BC, Canada
Send a message via ICQ to Duo
s_pics: The correct way to find RMS voltage to DC voltage in a rectifier circuit would be 28V/0.707, which is the same as 28V*1.414, which would be about 40V.
  Reply With Quote
Old 29th November 2006, 09:15 AM   #16
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Quote:
nuuk not sure I understand your gain factor
It's not only a question of how much you amplify the signal but whether the amplifier remains stable at a given level of gain!

This has been discussed many times on these forums so some searching may help you further. There are also some questions in this thread that could be answered on my GC FAQ page .
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 29th November 2006, 10:11 AM   #17
diyAudio Member
 
Easyamp's Avatar
 
Join Date: Nov 2003
Location: United states
My feedback statement was not a lack of understanding it is only to point out that to use this device with a gain of 10 would not be using it to its potential.

If your input device is capable of 1 volt peak to peak output which is fairly standard then you'd be getting .707v rms input this times 10 is 7 volts rms out and if you were driving an 8 ohm speaker this would get you about 6 watts. Even into 4 ohms a mere 12 watts. I will admit however using a device with a gbp as low as this one you will encounter problems near the upper bandwidth but not until you get above gains of 20.

You would be better served by an lm1875, not to mention your wallet. The lm1875 has a lower distortion figure anyway.
__________________
bumble bee tuna.
  Reply With Quote
Old 8th October 2007, 11:36 AM   #18
ybserge is offline ybserge  Belarus
diyAudio Member
 
Join Date: Dec 2005
Location: the moon
opa541 sounds better inverted, try and compare.
  Reply With Quote
Old 9th October 2007, 01:50 AM   #19
diyAudio Member
 
Join Date: Mar 2004
Location: Arkansas
Easyamp,
Your point is well made.
With a one volt input... a 10X gain would be quite dissappointing.

Common opinion in these forums seems to say that the OPA54x is more stable, and "sounds" better with a gain limited to about 10x... rather than using it at higher gains like you could with Overature series chipamps.

The solution is that most guys are adding an extra gain stage in the form of a buffer/preamp to make up the difference.
1v input->3X buffer/preamp->10X main amp = a gain of ~30.
In other words, let your preamp do half the work.
__________________
Writing is good exercize for the texticles!
  Reply With Quote
Old 9th October 2007, 09:56 AM   #20
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
There is no 'best gain' as so much depends on other equipment like pre amp and speakers.

Using a Burson Buffer with a gain of 6db, and 96db efficiency speakers, my OPA541 with a gain of 8 has more than enough PRAT.

So as ever, always consider your own system before taking general advise on such issues!
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  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
opa541 jaudio Swap Meet 3 18th February 2009 02:55 PM
Opa541-548-549 abid_rehan Chip Amps 3 9th August 2004 08:06 AM
opa541 sss Chip Amps 3 6th August 2004 11:27 AM
My very own OPA541 GC MikeF777 Chip Amps 4 9th December 2003 06:24 PM
opa541 pundip Solid State 5 2nd March 2003 07:08 PM


New To Site? Need Help?

All times are GMT. The time now is 04:51 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