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 27th April 2004, 02:50 PM   #11
speaker is offline speaker  United States
diyAudio Member
 
speaker's Avatar
 
Join Date: Mar 2004
Location: USA
This might be a project built on the premise of doing it just because you can. Can and should are separated by a wide chasm however.

speaker
  Reply With Quote
Old 27th April 2004, 02:58 PM   #12
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Hey, if you want to build something for the sheer craziness of it, knock yourself out. You will end up spending $50 in pots unless you get them free or surplus, in order to build something with much poorer performance than a $4 LM3875. On the other hand, with the output impedance so high already, you may not have to worry about circulating ground currents. (but maybe they will just fry the opamps, hard to say)
  Reply With Quote
Old 27th April 2004, 03:38 PM   #13
Stocker is offline Stocker  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Austin
Quote:
Originally posted by speaker
Can and should are separated by a wide chasm however.

Yes.

This is an idea that is probably a year away if it ever will be built. It was like a song stuck in my head that I couldn't get rid of so I made a thread about it.



As for the pots... There are 2-4 of them on ALL the PCBs on all our analog controllers. Bourns 3299 mostly, some 3262. I have loads of them as well.

How high is the output impedance of 200+ TL07x opamps in parallel?

__________________
Jesus loves you.
  Reply With Quote
Old 27th April 2004, 04:14 PM   #14
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Well, we know the voltage output is
  • 10V @ 2k (5mA)
  • 5V @ 175R (28.5mA)

deltaI = 28.5 - 5 = 23.5mA
deltaV = 5V
R= V/I = 5V/23.5mA ~ 212R

So 200 in parallel will be about 1 ohm output impedance, or a damping factor of 4.
  Reply With Quote
Old 27th April 2004, 05:02 PM   #15
Stocker is offline Stocker  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Austin
Gosh thanks!

I am beginning not to be surprised at how willing people here are to answer even dumb questions. Very helpful.

I was about to start thinking about heat dissipation in the individual packages and as a whole, and it occurred to me that even with LM324s we're talking less than a watt each, easily handled by little sinks on each. If I were to go with one big heatsink for the whole thing, it would likely be such a big piece of aluminum that it would never even get warm. cool.
__________________
Jesus loves you.
  Reply With Quote
Old 27th April 2004, 05:04 PM   #16
Banned
 
Join Date: Feb 2002
Location: As far from the NOSsers as possible
There is probably a good reason why you got them free at work.

Hint: They suck for audio.

Jocko
  Reply With Quote
Old 27th April 2004, 05:21 PM   #17
Stocker is offline Stocker  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Austin
Default Re: Using multiple (like 40) TL074s...

Quote:
Originally posted by Stocker
Obviously it would not be anything like a reference amplifier but...


ahem.

I know they are not ideal. To say that TL074s suck at audio is to put down a whole BUNCH of commercial gear that sounds just fine to a lot of people. LM324s you may have more of a point but for those of us with ringing ears and who mostly use music for background noise anyhow, even LM324s would probably satisfy "most" people if they didn't know they were there...

And I get them free at work because they are trash, and because my work has about as much to do with audio as anthropology.

But thank you for your constructive criticism
__________________
Jesus loves you.
  Reply With Quote
Old 27th April 2004, 05:55 PM   #18
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
To be honest, TL074 is bargain basement. We aren't even talking NE5532, which some treat as akin to the plague. (unjustly! if used properly)
  Reply With Quote
Old 27th April 2004, 07:44 PM   #19
Stocker is offline Stocker  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Austin
Actually it is bargain BIN...trash bin!
__________________
Jesus loves you.
  Reply With Quote
Old 27th April 2004, 09:57 PM   #20
Banned
 
Join Date: Feb 2002
Location: As far from the NOSsers as possible
Default Seriuosly......

I understand that they are free. I still wouldn't use them.

Jocko
  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
Multiple subwoofer/multiple amp question boogs Subwoofers 5 13th November 2007 04:36 AM
Multiple KEF B139s coloradosound Subwoofers 10 9th December 2006 08:13 PM
Are multiple ports better ? goldyrathore Subwoofers 38 7th July 2005 10:21 AM
multiple op's amp adason Solid State 3 2nd June 2005 09:04 PM


New To Site? Need Help?

All times are GMT. The time now is 07:08 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