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Old 21st March 2013, 01:59 AM   #181
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Quote:
Originally Posted by aj982 View Post
Haha. Nice.

I couldn't get myself to buy those cool looking Wimas...
Dude, go all out, PIO input caps, Wimas, Hell, Let's replace opamps with Burson modules. Burson Discrete Opamps
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Old 21st March 2013, 03:01 AM   #182
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Originally Posted by tamasic1 View Post
Dude, go all out, PIO input caps, Wimas, Hell, Let's replace opamps with Burson modules. Burson Discrete Opamps
here I thought lm4562 were good


Now this... when will it end...
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Old 21st March 2013, 10:30 AM   #183
danzz is offline danzz  Spain
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Originally Posted by tp4tissue View Post
here I thought lm4562 were good


Now this... when will it end...
A pair of 4562 are about 5$... A pair of the burson op-amp are 179$... I think its to much investment for a lepai... Im sure it worths in many other designs but a bit expansive for a 17$ amp... But good to know that those exist.
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Old 21st March 2013, 10:49 AM   #184
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Originally Posted by danzz View Post
No, I directly conected the iPhone as a source and some little speakers I made with some Tang Band w3 665SC I made for this purpouses...
But... would be safe to switch on the Lepai without any load or would be safer to use a couple of 6ohm 20W resistances?
I want to be sure there's no output DC before wiring the modded Lepai to my speakers!
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Old 21st March 2013, 02:55 PM   #185
danzz is offline danzz  Spain
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Originally Posted by Fukinagashi View Post
But... would be safe to switch on the Lepai without any load or would be safer to use a couple of 6ohm 20W resistances?
I want to be sure there's no output DC before wiring the modded Lepai to my speakers!
From the little I know those resistence shouldnt harm the amp If everything its ok, and measure the output...

Lets see what others that has lot more knowledge than me says...
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Old 21st March 2013, 02:57 PM   #186
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Without a load is fine BUT, do NOT remove the load while the amp is on, many many people have fried it that way.
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Old 21st March 2013, 07:38 PM   #187
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In general, it is better to test with a load. A pair of test speakers or the 6 ohm resistors. It completes the circuit. Without a dummy load, the meter itself becomes the (very high impedance) load when it is connected for a measurement.
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Old 22nd March 2013, 09:29 AM   #188
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Originally Posted by sofaspud View Post
In general, it is better to test with a load. A pair of test speakers or the 6 ohm resistors. It completes the circuit. Without a dummy load, the meter itself becomes the (very high impedance) load when it is connected for a measurement.
Thanks. I did try this morning using a couple of 6ohm resistors.
I read few tens of mV DC without modifications.
Now I will try this basic mod:

1) remove C30, C31, C20 and C21.
2) wire C30 and C31 pads to C20 and C21 (right side) through a couple of 2.2uF caps (Clarity Caps).

and test again.
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Old 22nd March 2013, 06:12 PM   #189
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Keep in mind, typical DC or noise tests use the inputs shorted to ground, so they aren't floating. If you measured a few tens of mV DC with the inputs floating, then you can only expect a better measurement with the inputs grounded.
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Old 26th March 2013, 08:07 AM   #190
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Here are my mods: two clarity caps as DC blockers and a couple of 10KOhm resistances in series to the signal (upper) as attenuators.
Two 47KOhm resistances as bypass (lower).
Thanks for help: despite the "minimal" modification the result is very interesting!

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