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Old 11th July 2010, 10:46 PM   #1721
pchw is offline pchw  United States
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50-ish should be OK with these FETs. My mini-Aleph is at high 50's in summer, and it has survived 2 summers.
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Old 11th July 2010, 10:52 PM   #1722
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Quote:
Originally Posted by ClaveFremen View Post
Salas,

which temperature is safe for the mosfets?

After using 2cm spacers mines are at 53C and before the case is ready another month will pass...

Is it better to disconnect it until case is ready?

Thanks in advance
45C is good for life. 55-60C sustainable but precarious. Does your Ref C pass DC if it gets it in the input?. Because your only fear would be to lose one supply and get full DC of the working supply on DCB1's output. If not, the most trouble would be to exchange a burned Mosfet, but unlike at 53C in a month's use.
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Old 11th July 2010, 10:54 PM   #1723
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Quote:
Originally Posted by pchw View Post
50-ish should be OK with these FETs. My mini-Aleph is at high 50's in summer, and it has survived 2 summers.
Yes up to 50C I would not worry for long term reliability with the 240's. If they were TO-220s maybe.
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Old 11th July 2010, 10:56 PM   #1724
Salas is offline Salas  Greece
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Quote:
Originally Posted by wushuliu View Post
Offset is good: .6mV/2mV
Voltage: I got a reading of 10.78v from the third pin of mosfet closest to the relays.

How do I check the current?
Read voltage across 10R Rset resistors, and divide by 10. The number is in Ampere.
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Old 11th July 2010, 11:05 PM   #1725
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Quote:
Originally Posted by Salas View Post
45C is good for life. 55-60C sustainable but precarious. Does your Ref C pass DC if it gets it in the input?. Because your only fear would be to lose one supply and get full DC of the working supply on DCB1's output. If not, the most trouble would be to exchange a burned Mosfet, but unlike at 53C in a month's use.
Thanks Salas,

the MyRef at the moment is DC-coupled too since I'm experimenting with components change and the input cap can mask a lot of differences...

The amp has a DC protection but... I'll think about it...
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Old 11th July 2010, 11:13 PM   #1726
Salas is offline Salas  Greece
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Install a proper value input cap regarding REF C's input impedance. Russian K40Y bypassed with FT1 22nF. Its a cheap and effective combo. That will guard your speakers in any case (except main amp's failure) in the future. Don't forget sources failures and experiments that can give something bad too. Unless that REF C's DC guard is bomb proof, better be safe than sorry for the years to come.
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Old 11th July 2010, 11:28 PM   #1727
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Quote:
Originally Posted by Salas View Post
Read voltage across 10R Rset resistors, and divide by 10. The number is in Ampere.
Hate to sound dumb here, but do you mean the 10R between the 100uf caps or R1?
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Old 11th July 2010, 11:44 PM   #1728
Salas is offline Salas  Greece
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The one you got in the 68//68 marked place.
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Old 11th July 2010, 11:49 PM   #1729
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The one you got in the 68//68 marked place.
Ok. I get 197mA/235mA...
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Old 11th July 2010, 11:59 PM   #1730
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It will not make any real difference, but you can parallel a 75R 1W resistor to the one resistor already installed on the 197mA side at a point, and get them currents almost the same. But don't lose sleep over it. Is the negative polarity the 197mA running one?
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