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-   -   Lepai 2020A+ (http://www.diyaudio.com/forums/class-d/226512-lepai-2020a.html)

peacocksuit 27th December 2012 05:33 PM

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 :).

Redshift187 27th December 2012 08:58 PM

http://www.diyaudio.com/forums/class...od-thread.html

Bypassing the op-amps for volume and tone (especially volume, since tone can be defeated) drastically reduces turn on thump.

Bare 28th December 2012 05:39 PM

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

nigelwright7557 28th December 2012 11:11 PM

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.

Redshift187 29th December 2012 06:28 AM

My red one had turn on thump, it still does, but it's way reduced after removing the volume opamp.

Fynn 29th December 2012 05:27 PM

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.

Redshift187 30th December 2012 06:33 PM

It obviously depends somewhat on the speakers too.


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