Tangent's ground channel w/o buffer - Page 2 - 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 29th July 2009, 10:02 AM   #11
diyAudio Member
 
nelsonvandal's Avatar
 
Join Date: Nov 2006
Quote:
Originally posted by morfic
Nelson, do you have some discrete buffers to suggest aside from sijosae's, impossible to google and not hit threads that in the end are based around his.
Sijosae was very productive. He has built amps with both diamond buffers and simple diode biased emitter followers. It's too bad it's the latter that most people associate with him. I prefer the diamond buffer. The DB has been around for a long time and is often used in monolithic opamps.

Some examples where diamond buffers are used in headphone amps:
http://tangentsoft.net/audio/ppa/amp2/
http://www.diamondstar.de/dDB_design.html
http://www.diyforums.org/
http://www.scribd.com/doc/6772415/Li...Specifications

Other buffer options are single BJT emitter follower, double emitter follower, complementary feedback pair
http://www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
http://ipodstudio.com/cms/media/lisa...complete_1.pdf

MOSFET source follower
http://www.amb.org/audio/mmm/

The options are numerous. Any power amp output stage could be scaled down to make a buffer for an opamp in a headphone amp.
Attached Images
File Type: jpg opamp db.jpg (90.2 KB, 189 views)
  Reply With Quote
Old 30th July 2009, 01:22 AM   #12
morfic is offline morfic  United States
diyAudio Member
 
Join Date: Jan 2009
Thanks Nelson, looking at finished amp's schematics....triggered a big "DUH" moment :/

Really appreciate the eye opener, had been googling around on a couple topics, turns out some Nelsonvandal on head-fi.org gave some pretty good info and sounded the anti audiophile snake-oil horn, always good when you accidentally find out you seem to listen to the right guy
Building the cmoy is part fun, part wanting to learn, what sounds how and what sounds the same or notably different.

Good thing on most the discrete buffers, i stand a chance to find needed parts locally....i hope.

Hopefully i get the amp parts before the weekend, so i can stop "talking" and start doing

Daniel
  Reply With Quote
Old 30th July 2009, 07:51 AM   #13
diyAudio Member
 
nelsonvandal's Avatar
 
Join Date: Nov 2006
I'm no wiz. I only try to be helpful. Don't take my words for granted, but I've listened to a lot of active ground circuits.
  Reply With Quote
Old 31st July 2009, 12:38 AM   #14
morfic is offline morfic  United States
diyAudio Member
 
Join Date: Jan 2009
Quote:
Originally posted by nelsonvandal
I'm no wiz. I only try to be helpful. Don't take my words for granted, but I've listened to a lot of active ground circuits.
No worries, in such a wide field, with such largely differing opinions, it just helps to start somewhere. Who knows down the road i may disagree with every single thing you said But w/o knowing anything myself i have no reason to do so and your help is much appreciated.

Digikey "outshipped" AudioXpress, so i get to look at parts w/o a board right now.
  Reply With Quote
Old 31st July 2009, 05:10 PM   #15
morfic is offline morfic  United States
diyAudio Member
 
Join Date: Jan 2009
One question i meant to ask, tangent suggests to use the same opamp and buffer combination for ground channel as for L/R, and it seems i can mix and match opamps and buffers.
But are there useful configurations where there is only a buffer in the ground channel, but not on L/R. Or where there is a buffer on L/R but not the ground channel?

Or is there indeed no use in a configuration that is this asymetrical?
  Reply With Quote
Old 31st July 2009, 07:44 PM   #16
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
an active ground channel has to handle both L&R channel load currents, the worst case is 2X the current in either signal channel so the gnd buffer should have higher current sink/source capability than the signal channel
  Reply With Quote
Old 31st July 2009, 08:06 PM   #17
morfic is offline morfic  United States
diyAudio Member
 
Join Date: Jan 2009
So in essence it could make sense to use a buffer only on the ground channel if the L/R channels can handle say 50mA each w/o a buffer to add a buffer to the ground channel alone, just to make sure it can handle the 100mA total.

Or if the L/R dual channel opamp can source 50mA per channel to combine it with an ground channel opamp that can source 100mA and not use a buffer on any of the 3 channels at all, until a deficiency in the amp is found that a buffer addresses.

Would either comment be correct to say?

If the ground channel is capable of less, will it simply become the limiting factor or are there negative effects beyond the imposed limit?
  Reply With Quote
Old 2nd August 2009, 05:20 AM   #18
morfic is offline morfic  United States
diyAudio Member
 
Join Date: Jan 2009
Are BUF634 really stackable, i've seen them used piggyback soldered to each other.

If i use one BUF634 per L and R, then i'd need 2 BUF634 on ground channel (or an equivalent capable of the same current, and i'm not aware of an IC of doubling it, LME49600 has same current with a higher short circuit current capability)

I'd like to try BUF634 (to help on the board i think i'd try TO-220) if i could just "double up" for the ground channel.

Discrete buffers would be a next step i think. (mainly a space issue on these boards (D4 by DH Labs))

Thanks,

Daniel
  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
Multi-channel Ground Lift Bigun Solid State 1 20th April 2009 07:43 PM
[help] pimeta ground buffer heating up jchanhm Chip Amps 0 6th June 2007 05:38 AM
ground channel GC pINO Chip Amps 9 12th December 2006 09:30 AM
Active crossover & buffer stage for a 5 channel amp sunil Chip Amps 9 15th December 2004 08:10 AM
Ground loop caused DAC channel to go out--what is likely to have happened? Grindstaff Digital Source 0 4th December 2004 10:48 AM


New To Site? Need Help?

All times are GMT. The time now is 06:21 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