could the F5C or F5T be run at 40v rails? - diyAudio
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Old 26th November 2012, 01:39 AM   #1
JZatopa is offline JZatopa  United States
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Default could the F5C or F5T be run at 40v rails?

I'm curious if the F5C or F5T could be run at 40V rails? Is that still to high for the cascoded frontend?
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Old 26th November 2012, 03:59 AM   #2
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hello. with cascoded FR. it can be run at +/-40V rails.
but you need at least 3 pairs of outputs to get anything out of it.
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Old 26th November 2012, 04:33 AM   #3
dazed2 is offline dazed2  Canada
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Quote:
Originally Posted by AudioSan View Post
but you need at least 3 pairs of outputs to get anything out of it.
what do you mean by that?
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Old 26th November 2012, 04:54 AM   #4
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Quote:
Originally Posted by dazed2 View Post
what do you mean by that?
becouse out over that, it can be hard for only one pair of input J-fets.
well. it can handle 4 pairs. 3pairs may be the better chose.
and with +/-40V rails. you want to get someting out of it. with somewath high bias. to get full out of +/-40V you need 2.4A bias
that is at 8ohms.

Last edited by AudioSan; 26th November 2012 at 05:02 AM.
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Old 26th November 2012, 07:27 AM   #5
JZatopa is offline JZatopa  United States
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Could it be done with as little as 2 pairs?
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Old 26th November 2012, 07:43 AM   #6
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yes. for v2 turbo.
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Old 27th November 2012, 02:14 AM   #7
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Cascode vill take 40 V rails

But to keep thermal down (max 50 w disipation for each mosfet with proper heath sinks)
you wuld have to bias at 1 A for each mosfet with a bit of safety margin
So you run out of class A at about 8 V (but duble cek my maths) which ain't bad depending on speakers and listening abits.

To find out how much power you need cek this out
A Test. How much Voltage (power) do your speakers need?
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Old 27th November 2012, 02:54 AM   #8
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With adequate sinking, you could consider 1 pair, but you wouldn't want to
be abusing it.

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Old 29th November 2012, 03:44 AM   #9
JZatopa is offline JZatopa  United States
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Thanks for the help guys, unfortunately I had to pass on the transformer I was going to use. I guess my F5T is going to have to wait.
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