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Mace_be  
#1 Posted : Thursday, June 28, 2012 12:39:34 PM(UTC)
Mace_be

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Hi,
I was testing my legato for the first time.
Its V3.1.0 in combination with the Placid HD BP set.
At first the there was a voltage sag to about 7V at both sides.
I checked solder en resoldered some connections.

The problem was solved.


Due to the heat of the 1W resistors on the Legato I have lowered the output voltage to 13.5V
Now the big 1W resistors are about 62°Celcius or 140°F measured with K-Type Thermocouple

The Fets and IC does also get warm.
Is that normal ?

My Placid HD BP delivers 400mA but shunts about 200mA of it.
Is this normal ? I've read that the Legato uses about 350mA dependend of the Voltage setting.

I have also changed the Heatsinks of the placid HD's. they get about 64°C or 145°F
Just to make sure that everything is alright before i connect the buffalo DAC Drool

The temperature in the picture is offcourse higher because the Placid needs to shunt all the supplied power.
Its about 200mA less when the Legato is connected.

Edited by user Thursday, June 28, 2012 12:52:42 PM(UTC)  | Reason: Not specified

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avr300  
#2 Posted : Thursday, June 28, 2012 6:57:49 PM(UTC)
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If you keep the shunted current around 100mA@~13v output, you will be fine.

Try firing it up and see what's happens.
thanks 1 user thanked avr300 for this useful post.
Mace_be on 6/28/2012(UTC)
Mace_be  
#3 Posted : Thursday, June 28, 2012 7:06:56 PM(UTC)
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I already fired everything up ! and it sounds Super! Currently listening via the headphones.
Sweet sound !
Currently the Placid hd bp is shunting 200mA so i am going to lower that.

Does everybody use the legato at 15V or also somebit less like me ?
Or am i to paranoid about heat :D

In the end, i am going to mount to Placid to bigger sinks.
I'm thinking of buying an enclosure of modushop.biz the 3U pasante dissepante and mount the placid's on the sinks.
avr300  
#4 Posted : Thursday, June 28, 2012 7:12:42 PM(UTC)
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I'm running at +-12.2v and it plays nicely - and at a relatively reasonable temp.

At +-15v I can't control the heat.

Edited by user Thursday, June 28, 2012 7:13:28 PM(UTC)  | Reason: Not specified

Mace_be  
#5 Posted : Thursday, June 28, 2012 7:17:09 PM(UTC)
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I think i have to also readjust the output when inside a case cuz of the resistors and fet's,
I don't want it to die and damage my buffalo.

Or maybe install a small silent low speed turning fan to just get some airflow.
avr300  
#6 Posted : Thursday, June 28, 2012 7:19:00 PM(UTC)
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Yes, good idea.
Russ White  
#7 Posted : Thursday, June 28, 2012 11:58:25 PM(UTC)
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If it is a legato 3.1 it is very robust, you should have no fear running at with 15V rails. :)

I do.

Still it sounds very good even at lower rails, so do what you feel most comfortable doing.

I am very pleased you like it.
Mace_be  
#8 Posted : Friday, June 29, 2012 9:02:19 AM(UTC)
Mace_be

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I measered that the legato takes on one side of the power supply about 20mA less. then the other.
The Supplied current is about 2 a 3 mA different on each side.

Russ White  
#9 Posted : Friday, June 29, 2012 6:25:08 PM(UTC)
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Sounds perfectly normal. :)
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