This is not just another gainclone - Page 139 - 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 20th March 2003, 04:14 PM   #1381
Philo is offline Philo  United States
diyAudio Member
 
Join Date: Jul 2002
Location: Ever sunny San Diego
MatttCattt,
Can I ask why youare limiting your current? I have both 541 and 549 prototypes set up now and and just shorted the leg. The amps sound great and have had no problems!
__________________
Philip
"If you didn't make it with your own two hands, its not really yours".
  Reply With Quote
Old 20th March 2003, 04:19 PM   #1382
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Hi Philo,

I'm currently building OPA549 amp. The rails can't go higher than +/-30V and pins 6 (ref) and 8 (I lim) connect to ground, right? Are you using inverted, minimized config.? Any other areas worth consideration?
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 20th March 2003, 04:24 PM   #1383
Mad_K is offline Mad_K  Norway
diyAudio Member
 
Mad_K's Avatar
 
Join Date: Sep 2002
Location: Norway
Quote:
Originally posted by Philo
MatttCattt,
Can I ask why youare limiting your current? I have both 541 and 549 prototypes set up now and and just shorted the leg. The amps sound great and have had no problems!
The 549 is current limited at 10A when you short I_lim.
The 541 in not limited at all when you do this. You won't have a problem with this approach until the you overdrive the amp or short the outputs. If the output of the 541 is shorted, you will have your rail voltage over you speakers If you draw more current than adviced, the chip may go up in smoke, and your speakers might be
__________________
Mads K
  Reply With Quote
Old 20th March 2003, 04:41 PM   #1384
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Quote:
Originally posted by Peter Daniel
Hi Philo,

I'm currently building OPA549 amp. The rails can't go higher than +/-30V and pins 6 (ref) and 8 (I lim) connect to ground, right? Are you using inverted, minimized config.? Any other areas worth consideration?
Whilst we wait for Philo's response, I thought I'd share my experiences.

I connected ref and lim to each other, then to ground, left the status pin floating, and used the minimised inverted config with the addition of adding back the 1uf cap across the + & - pins.

I used (for testing only) a 75VA 18-0-18 AC traffo, as my bigger 300VA that I use for my LM3875 and OPA548 at 24-0-24 AC seemed to cause the inbuilt protection to cut in, even though it gave only 28.5V regulated

(edit) I meant to say 22-0-22, not 24-0-24
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 20th March 2003, 04:56 PM   #1385
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
That's what I plan to do. As I recall you mentioned it sounds better than LM based amp. Did you try TDA7294?
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 20th March 2003, 05:32 PM   #1386
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Quote:
Originally posted by Peter Daniel
Did you try TDA7294?
Not yet, no money for hobbies at the mo...

I think I might have also have changed the value of the feedback resistor, but I can't remember why, and what to, and I'm away from home at the moment for a few days so I can't check!
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 20th March 2003, 05:33 PM   #1387
Elkaid is offline Elkaid  Canada
diyAudio Member
 
Elkaid's Avatar
 
Join Date: Jan 2003
Location: Canada
Send a message via MSN to Elkaid
Quote:
from Peter Daniel As I recall you mentioned it sounds better than LM based amp. Did you try TDA7294?
Now that I've finished my LM3875 based GainClone, I'll go back on my TDA7294 based amp so expect news from me soon.

Just to make a short story, I had some problems with TDA7294 concerning oscillation and mysterious explosions (I finally found out that it was due to overvoltage hmmm hmmm).

The TDA7294 has very impressive dynamics and detailed sound (not to mention high output power. If more power is needed, there's the TDA7293 which accepts higher voltage rails and can be bridged using several 7293 ICs)
  Reply With Quote
Old 20th March 2003, 05:34 PM   #1388
Bricolo is offline Bricolo  France
diyAudio Member
 
Bricolo's Avatar
 
Join Date: Nov 2002
Location: Grenoble, FR
Quote:
Originally posted by Peter Daniel
That's what I plan to do. As I recall you mentioned it sounds better than LM based amp. Did you try TDA7294?
AFAIK, this chip is possessed by evil
  Reply With Quote
Old 20th March 2003, 05:36 PM   #1389
Bricolo is offline Bricolo  France
diyAudio Member
 
Bricolo's Avatar
 
Join Date: Nov 2002
Location: Grenoble, FR
Quote:
Originally posted by Elkaid



Just to make a short story, I had some problems with TDA7294 concerning oscillation
did you manage to solve them?
  Reply With Quote
Old 20th March 2003, 05:57 PM   #1390
Bricolo is offline Bricolo  France
diyAudio Member
 
Bricolo's Avatar
 
Join Date: Nov 2002
Location: Grenoble, FR
Default MKP caps

My local resealer hadn't MKP caps, he gave me 0.1uF MKH istead
are they also good? I don't know what does those caps name mean
  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
Freebird + Gainclone = "integrated" gainclone? bikehorn Chip Amps 9 5th January 2006 04:07 PM
JLH v Gainclone? Jezz-the-Fezz Solid State 5 12th December 2005 01:08 PM
Big gainclone steven344 Chip Amps 10 23rd November 2005 08:58 PM


New To Site? Need Help?

All times are GMT. The time now is 03:08 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