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Old 17th January 2013, 05:37 PM   #1361
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Thanks Virpz I look forward to seeing the tutorial. This is my first time modding an amp and there are so many pages in this thread it gets confusing.

Since I removed the R35 and R34 resistors do I have to replace those now? If so does anyone know what they are?

Thanks for the help

Last edited by frankslan; 17th January 2013 at 05:39 PM. Reason: a word
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Old 20th January 2013, 11:21 PM   #1362
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R8 and R10 and the Rin resistors while R9 and R11 are the Rfeed resistors
I just got some resistors 22k and 33k half watts. Do I just put the resistor connecting r8 to r10 and r9 to r10 ?
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Old 8th February 2013, 09:59 PM   #1363
blossom is offline blossom  New Zealand
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Default Small problem.

Hi guys, good to see people still playing with these. Anyway I might have damaged mine, not sure, thought I'd just post and see if anybody can help me.

The problem is it does not put any sound out. LOL. But i think i know why, I did a few mods to mine as you can see in the pic. But what happened is, where I bypassed the O.P. amp stage, the 2 wires ended up touching each other just after they come away from the board near the RCA plugs. Anybody know if this could be a course for the TA2020 chip to fail? Or perhaps it can be reset? If anybody in the know could give there opinion i would be greatfull.

P.S. this picture is taken after a rewire.
Click the image to open in full size.
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Old 11th February 2013, 09:06 PM   #1364
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Default 10,000 uf cap?

Quote:
Originally Posted by ROBJudkins View Post
Hi my amplifier came today (4th july 2012) and has a red circuit board i have replaced vonage 2a power supply with a xbox 360 16.5a power supply i know its a bit overkill as the thing will only drain about 4-5a and also the 2200uf power cap has been replaced with a much bulkier 10,000uf cap, i am not experiencing the pop when turning on and off and also not experiencing the hiss from the tone controls but my relay isnt engaging when i turn the amplifier up to distortion, i am not sure but could there be a problem with my amplifier?

thanks rob
Did you calculate that higher value? Others suggest 4700@16v. Thinking about going to 25v for more voltage headroom.
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Old 12th February 2013, 05:39 PM   #1365
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Hi all,

I just wanted to say thanks to all for this great thread. I've owned a 2020B (in 2020A+ enclosure) for a while now and on the weekend I got up the courage to bypass the tone control and opamp. I used 2.2uF, 63v ROE bipolars. The leads were long enough that I went point to point without needing any wire. The amp sounds much better now. Going to do the output inductors and big power cap at some point.
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Old 13th February 2013, 03:26 AM   #1366
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Hi, I'm looking to get another one of these Lepai amps to mod. I'm wanting to put it in a new enclosure and would like to have the power supply inside the enclosure.

Will a power supply like this work?
12V 5A 60W Switch Switching Power Supply Driver for LED Strip Light Display USA | eBay

Or is there something better out there? For my use, having a power brick external of the amp enclosure will not work.
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Old 14th February 2013, 08:29 PM   #1367
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Quote:
Originally Posted by talladega View Post
Hi, I'm looking to get another one of these Lepai amps to mod. I'm wanting to put it in a new enclosure and would like to have the power supply inside the enclosure.

Will a power supply like this work?
12V 5A 60W Switch Switching Power Supply Driver for LED Strip Light Display USA | eBay

Or is there something better out there? For my use, having a power brick external of the amp enclosure will not work.
Looks perfect, however I am not an authority on this.
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Old 14th February 2013, 11:33 PM   #1368
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Newbie Alert !

Yes, I'm new to the world of Lepai and would like to ask a very basic question as I want to buy one - one of the latest models.

I'm getting confused with the models eg. Lepai TA2020, LP2020, LP2020a, LP2020a+ etc.

Can someone point me to the latest model (I believe it has the anti-pop relay built in) and if anyone can suggest an eBay seller they were happy with that would be a bonus.

Thanks in advance.
JoJo
Thu14feb13
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Old 15th February 2013, 12:19 AM   #1369
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Quote:
Originally Posted by cogitech View Post
Looks perfect, however I am not an authority on this.
This is what my full plan is to do.

Hopefully my poor mspaint drawing is understandable.

Click the image to open in full size.

I've been told by some people that EMI may cause an issue if I dont shield the amp from the raspberry pi and wifi adapter and the power supply.
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Old 15th February 2013, 02:13 AM   #1370
blossom is offline blossom  New Zealand
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Quote:
Originally Posted by Virpz View Post
If you want to correctly bypass and adjust the gain on your lepai then you need to connect directly to the RCA inputs instead of pads on R35 and R34 ( C31 and C 30 on pcb 120305 ) you should know that:

R8 and R10 and the Rin resistors while R9 and R11 are the Rfeed resistors. These are the resistors that adjust the gain. Look into the TA2020 datasheet to get the full explanation.

- For ipod and portable players with built in volume control use 22K for Rin and 39K for Rfeed

- If you want to play it safe with and set your lepai for general use you should use 22K for Rin and 22k for Rfeed.

- For signals coming from a pre-amplifier you can go for 56K for the Rin and 22K for the Rfeed

I will post an definitive mod list for the lepai in a few days . I just need the time to do it correctly with pictures and everything else.
I will also show how to make the "switch" button work as it should; bypassing tone controls for real.

[]'s
Looking forward to the definitive post.
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