Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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 September 2011, 07:36 AM   #1
diyAudio Member
 
Join Date: Aug 2011
Default Audio Buffer for 8Ohm speaker

I need to drive 8Ohms speaker from the output of a PGA2311.
The datasheet for PGA2311 mentions that it can directly drive a load of 600Ohms.
Can i use a series resistor to match up with the load ? (would that be a right approach)
Or would it be better to build some unity gain audio buffer to drive the 8Ohms headphone speakers ?
The output of PGA2311 is a zero-crossing one (no DC offset).
LM380 and LM386 have a fixed internal gain, which is undesirable for my application.
Also, I'd like to use a dual rail supply OPAMP instead of a single rail supply to elimitae the bypass capacitors which create a click and pop when i turn the signal on/off.
  Reply With Quote
Old 2nd September 2011, 09:20 AM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
To drive an 8 ohm load you will require current gain. If that's all you need, something like a BUF634T would work. If you need voltage gain, then you could simply use an opamp in front of it with your desired gain, or you could program the needed gain into the PGA2311
  Reply With Quote
Old 2nd September 2011, 09:30 AM   #3
diyAudio Member
 
Join Date: Aug 2011
Hey jaycee, ya i need some current gain, i am changing the voltage gain on PGA2311 and don't want it further amplified by some opamp..
I will check with BUF63T
Thanks
  Reply With Quote
Old 2nd September 2011, 10:22 AM   #4
diyAudio Member
 
Join Date: Aug 2011
BUF634T seems to be exactly what i need !
Is there any similar buffer with 500mA output current ?
Also, can you point to any buffer which has a control input ?
So i can turn the output on/off using a controller ?
  Reply With Quote
Old 2nd September 2011, 02:43 PM   #5
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
If you want higher than 250mA you are probably going to have to do it with discrete parts. For example a diamond buffer arrangement (same as what the BUF634T has internally) with BC639/640 outputs.
  Reply With Quote
Old 8th September 2011, 08:17 PM   #6
tonal is offline tonal  Greece
diyAudio Member
 
Join Date: Apr 2007
PGA2311 works with +/-5 Volts and, according to the datasheet, it will deliver +/-3.75V on its output.
If a buffer (no voltage gain) is to be used to drive a pure ohmic 8Ω load then the buffer should be capable of delivering something less than 0.47A and an average power of 880mW.
If that works for you then go ahead, but if you need more power then you must consider using a power amplifier and not just a voltage buffer.

BUF634 is not capable to deliver that much current, because 550mA is what it takes to activate its internal short circuit protection and not a sustained output current which is about 250mA.
  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
4ohm output transformer with 8ohm speaker nige838 Tubes / Valves 2 2nd November 2010 07:21 AM
Jensen C10R 8ohm Guitar Speaker dsavitsk Swap Meet 1 30th April 2010 07:08 PM
8ohm resistor in series with 8ohm speakers for a 16ohm OT? Reidy- Tubes / Valves 8 10th January 2010 11:25 PM
4ohm Car Speaker to 8ohm Use? PrecisionAudio Car Audio 1 20th April 2006 02:40 AM
8ohm speaker on 15 or 3.5 ohm tranny kopite Tubes / Valves 1 6th July 2005 08:05 AM


New To Site? Need Help?

All times are GMT. The time now is 04:19 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