Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

LM6172 oscillating
LM6172 oscillating
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
Thread Tools Search this Thread
Old 27th January 2004, 08:35 AM   #11
Saurav is offline Saurav
diyAudio Member
Join Date: Sep 2002
Location: Oregon, USA
Hmm... that's going to be tight - I looked at my layout, and it'll be relatively easy to do for one channel, but quite a bit harder for the other.

Things are looking better now. I added a feedback resistor to the inverting input and another resistor from there to ground. Put a cap across teh feedback resistor. Turned out to be too big, killed teh treble (this is the one cap in my stash that I don't know the value for), I'll pick up appropriate caps tomorrow I think. Anyway, those reduced the oscillations but didn't eliminate it. Finally I used another suggestion from the app note (which the kit instructions also had) and increased the input series before the first preamp to 2K ohms. Apparently this reduces the overall slew rate of the system. Anyway, that took care of pretty much all the oscillation. The output is still kinda fuzzy, but I'm down on the lowest setting on the voltage and the timebase on my scope, so I can't reliably make any judgement calls any more.

I can't hear any high pitched squeal from the speakers (I can if I remove the caps, but it's very low, and the scope shows a little oscillation with the cap removed). So right now I have the cap out, I'll put in caps of the correct size tomorrow.
  Reply With Quote
Old 27th January 2004, 02:56 PM   #12
Saurav is offline Saurav
diyAudio Member
Join Date: Sep 2002
Location: Oregon, USA
I shouldn't post after midnight. Did I get that right? This cap should form a low pass filter, so to push the corner frequency up higher, I'll need to reduce the value of the cap. Correct?
  Reply With Quote


LM6172 oscillatingHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB: Lm6172 Dip AR_sound Swap Meet 0 19th October 2006 03:05 AM
Wtb: Lm6172 & 6171 pablosapiens Swap Meet 2 22nd January 2006 06:21 PM
LM6172 sound jesper Solid State 1 24th December 2005 05:17 PM
Modify LM6172 for 12V justpoor Digital Source 5 11th September 2005 06:30 PM
lm6172 class a bias? crippledchicken Parts 0 3rd September 2004 05:33 AM

New To Site? Need Help?

All times are GMT. The time now is 08:21 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio