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Old 10th April 2012, 03:58 PM   #1831
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Originally Posted by Nick77 View Post
I finally decided to install a couple of 4.5R mills resistors i had on hand, which replaced the Mills 10R. Resolution was a very nice bump, well worth the effort. Barely ran warm before but running about 100 degress on the sinks (37.7 celsius).

Cant find acceptable temp ranges, thanks. Using large L bars bolted to chassi

Is 100 degrees an acceptable temp?
I went from 10R to 3R0 and the sinks got too hot for my liking, They were stable at about 55 Degrees C.

I might just try 4R7 as you have - allbeit 4R5 in your case.

Last edited by KatieandDad; 10th April 2012 at 04:04 PM.
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Old 10th April 2012, 04:02 PM   #1832
Salas is online now Salas  Greece
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Nick, maybe a picture as sinked?
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Old 10th April 2012, 06:22 PM   #1833
Nick77 is offline Nick77  United States
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Had some larger sinks on hand but ran out of chassis space.

Click the image to open in full size.
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Old 10th April 2012, 06:32 PM   #1834
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I still cant see why mine were getting so warm at 3R0.

Maybe I was just being too cautious. After about 30 mins with the lid off my sinks were at 55 Degrees C or so. I felt, that, with the lid on, things would just get too warm and things would start to fail.

Maybe that's me being too cautious. Maybe 3R0 was too far. I am tempted to try 4R7 though - I've already ordered them.

I seem to recall that the heatsinks were about 3.6 Deg C/W. I've used one per side so there are two IRFPs on each sink.

At 10R0 they run at about 30-35 Degrees C.

Last edited by KatieandDad; 10th April 2012 at 06:34 PM.
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Old 11th April 2012, 06:20 AM   #1835
Siberia is offline Siberia  Lithuania
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Quote:
Originally Posted by Salas View Post
Run a wire from 0 PSU on DCB1 to its chassis.
Worked like a charm. Ευχαριστώ!
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Old 11th April 2012, 01:49 PM   #1836
Salas is online now Salas  Greece
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Parakalw! (=You are welcome).
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Old 12th April 2012, 08:14 PM   #1837
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Default Attenuator question

I'm planning a 6-channel DCB1 along these lines:
Click the image to open in full size.
with Hypnotize boards in place of the DACT modules.

DACT recommends 10K pots for the master and individual channel controls, while Mr. Pass recommends a nominal 25K. I've a mind to use 20K as a compromise (PEC carbon for each channel and Goldpoint for the master), though I don't know how having two pots in a row affects the total input impedance. Can anyone enlighten me as to how the attenuator impedance affects the sound? Any recommendations?
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Old 12th April 2012, 11:27 PM   #1838
Salas is online now Salas  Greece
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Use 10K pots so not to exceed 20K in series. Those Jfets have enough input capacitance to start losing noticeable bandwidth after that driving impedance level.
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Old 13th April 2012, 02:54 AM   #1839
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OK thanks Salas
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Old 13th April 2012, 09:28 AM   #1840
AndrewT is online now AndrewT  Scotland
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A pair of series connected pots to control volume !!!!!

Have you considered each pot as a receiver and then again as a transmitter?

The Source sees the pot1 and the cable in between.
Pot1 sees the source and the cable in between.

Pot2 sees pot1 and the cable in between.
Pot1 sees pot2 and the cable in between.

Pot2 sees the DCB1 and the cable in between.
The DCB1 sees pot2 and the cable in between.

You have six IN/OUT systems from Source to DCB1.

You must satisfy good practice in transferring signal through all six systems.

What you are proposing has not been thought through thoroughly.
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