Lepai 2020A+ - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 December 2012, 05:33 PM   #1
diyAudio Member
 
Join Date: Feb 2012
Default Lepai 2020A+

Hi. I am using one of these little amps while my main hifi amp (Vintage Toshiba sc-330) is out of action and awaiting repair.

I am concerned that when I switch this thing on and off the cones on my speakers pop and the bass drivers move slowly back and forth by a considerable amount.

The speakers in question are Wharfdale E50, lovely old things, not something I want to damage (naturally!).

Is this sort of speaker come movement and popping anything to be concerned about?

I know there are some modifications that can improve the performance of these Lepai amp's and I'm aware of the modification thread. However its a massive thread and mentions all sorts of modifications. I don't know if any of the mods would help with the problem Im experiencing or now?

Any help much appreciated.

Thank you .
  Reply With Quote
Old 27th December 2012, 08:58 PM   #2
diyAudio Member
 
Join Date: Aug 2008
LP-2020A+ mod thread

Bypassing the op-amps for volume and tone (especially volume, since tone can be defeated) drastically reduces turn on thump.
__________________
Tyler
  Reply With Quote
Old 28th December 2012, 05:39 PM   #3
Bare is offline Bare  Canada
diyAudio Member
 
Join Date: Dec 2001
Location: vancouver
Tone defeat doesn't actually remove the Tone junk...it just pretends to.
Do you seriously expect sophistication in a $15 amp ?
There is was no (pre mods) turn on thump with any of My red pcb Lepais' .
Good chance yours is pre-broken?
READ the WIKI at least
  Reply With Quote
Old 28th December 2012, 11:11 PM   #4
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
I don't know about your model but the 2092 based class d amps have a reset capacitor.
However if you start to use very large decoupling then clicks, pops and siren type sounds can occur.
I found the only way around it was to add a small microcontroller that detected when power supply volts were low and held the 2092 in reset.
  Reply With Quote
Old 29th December 2012, 06:28 AM   #5
diyAudio Member
 
Join Date: Aug 2008
My red one had turn on thump, it still does, but it's way reduced after removing the volume opamp.
__________________
Tyler
  Reply With Quote
Old 29th December 2012, 05:27 PM   #6
Fynn is offline Fynn  Germany
diyAudio Member
 
Join Date: Nov 2012
My red PCB 2020a+ had a power off thump and a very silent power on thump.

After bypassing the opamps, there were no more pop noises for me anymore.
  Reply With Quote
Old 30th December 2012, 06:33 PM   #7
diyAudio Member
 
Join Date: Aug 2008
It obviously depends somewhat on the speakers too.
__________________
Tyler
  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
LP-2020A+ mod thread Redshift187 Class D 296 20th July 2014 02:08 AM
TA2024 SA-36 or LP-2020A Terrymm Class D 3 28th September 2012 05:34 PM
Help with Lepai LP-2020a+ ChrisChris Class D 5 14th September 2012 04:24 PM
Lepai LP-2020A+ Balance Problem Nightcry7 Class D 3 14th September 2012 04:16 PM
New to Lepai surfaudio Class D 0 5th May 2012 02:35 AM


New To Site? Need Help?

All times are GMT. The time now is 06:56 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