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Old 23rd November 2007, 03:57 AM   #1481
jleaman is offline jleaman  Belgium
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Default F4

Ok, so after a week of listening then putting al together, I LOVE THIS AMP, very VERY good detail. It is dead A$-$ Quiet, I have to admit it, they are quieter then my aleph mini's ) I'm talking about noise ratio and humms : there is literally NONE!

Pure sound, I should build another.

The one bad thing, DAM THEY GET HOT.
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Old 23rd November 2007, 05:35 AM   #1482
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Another reason to try water cooling?
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Old 23rd November 2007, 05:37 AM   #1483
jleaman is offline jleaman  Belgium
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Quote:
Originally posted by carpenter
Another reason to try water cooling?

Not going to happen

i just turned bias to 300mv tho so shes a little cooler
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Old 23rd November 2007, 06:07 AM   #1484
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I'm considering the possibility of separating the power rails to the Mosfets from the jfets, and running the Mosfets at higher voltages than the jfets--about twice as much voltage, actually. Water cooling will be useful.
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Old 23rd November 2007, 06:12 AM   #1485
jleaman is offline jleaman  Belgium
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Quote:
Originally posted by carpenter
I'm considering the possibility of separating the power rails to the Mosfets from the jfets, and running the Mosfets at higher voltages than the jfets--about twice as much voltage, actually. Water cooling will be useful.

would be good, however loud and just a pain for me..
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Old 23rd November 2007, 09:10 AM   #1486
Jaac is offline Jaac  Netherlands
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Default Re: F4

Quote:
Originally posted by jleaman
Ok, so after a week of listening then putting al together, I LOVE THIS AMP, very VERY good detail. It is dead A$-$ Quiet, I have to admit it, they are quieter then my aleph mini's ) I'm talking about noise ratio and humms : there is literally NONE!

Pure sound, I should build another.

The one bad thing, DAM THEY GET HOT.
Do you have any idea how hot ? Firt my aleph 5's where hot but then i touched the sinks of a pair of xa100 at my work, they where even hotter so no problemo ! around 60 degree. Nice amp btw
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Old 23rd November 2007, 03:13 PM   #1487
lykkedk is offline lykkedk  Denmark
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Quote:
i just turned bias to 300mv tho so shes a little cooler
Hmm... why don't you just set bias to 200 or 250mV (schm. related)... I can't hear any sonic difference if i crank mine up to e.g. 300 (schm. i used is the 250mV bias) Later changes's in F4 schm. the gate resistor's (among other canges too) change and bias go down to 200mV.

You really have to have the F4 turned on, for some time, and adjusting the DC-offset, when she is thermic stable (mine 2... are 1,5hour to become 100% stable), having at this time a temperature of ~40-45 C - with 250mV bias meassured on pwr. resistors.

All this is vere important i think. I leaved mine two monoblocks playing when having a party not so long ago, for around 12hour's ... still having the same temperature... Jleaman, i think that its your'e real goal for now (judging by the size of your'e heatsink's i don't think you should go further than the described bias)

Jesper.
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Old 23rd November 2007, 03:18 PM   #1488
skseah is offline skseah  Singapore
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Hi,
Here is my F4 with Conrad Heatsinks..bias set at 200mV..hot but seems OK for the hot temperature in Singapore.
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Old 23rd November 2007, 03:19 PM   #1489
skseah is offline skseah  Singapore
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Hi,
Here is my F4 with Conrad Heatsinks..bias set at 200mV..hot but seems OK for the hot temperature in Singapore.[IMG]http://[/IMG]
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Old 23rd November 2007, 05:21 PM   #1490
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Quote:
Originally posted by skseah
Hi,
Here is my F4 with Conrad Heatsinks..bias set at 200mV..hot but seems OK for the hot temperature in Singapore.

Handsome amp!
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