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Old 3rd April 2008, 10:41 PM   #11
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Thanks for the reply although I'm not entire sure I understand it. (Newbie )

So adjust P1 so that the drain on Q2 is half of the drain on Q3?

And adjust P2 so that it reads 21V in front of C1?

Start these adjustments with the pot all the way counter clockwise?
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Old 3rd April 2008, 11:33 PM   #12
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Quote:
Originally posted by Marsfrogie


So adjust P1 so that the drain on Q2 is half of the drain on Q3?

And adjust P2 so that it reads 21V in front of C1?

Start these adjustments with the pot all the way counter clockwise?


P1 to read the 21V in front of C1 . . .
P2 to earn the best sound with your ears . . .
Doesn't matter. Just adjust to all directions. The amp will be still safe.
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Old 3rd April 2008, 11:40 PM   #13
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Best to assume the value of the pot will be close to that of
the resistor used in ZV9. Raise the value as much as you like,
but I don't recommend going more than 20% or so lower than
the stock value.
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Old 3rd April 2008, 11:41 PM   #14
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Hello Marsfrogie, Here's a heatsink that should do the job. Cut in half for two heatsinks. I bought one of the same from this seller last week. It arrived pretty quickly and it is as big as described.

http://cgi.ebay.com/Aluminum-heatsin...QQcmdZViewItem


Peace,

Dave
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Old 3rd April 2008, 11:55 PM   #15
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Cheers! Thanks for the responses. I want to try to build the heatsink myself first just so I can say that I did it. If it doesn't work I'll end up purchasing one. It's looking like this is going to be one big heavy tank of an amp. The transformer that I got in was HEAVY!

One other thing. How does the voltage get from 2X18 to 46V input at the board? Is that the bridge rectifier doing that?
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Old 4th April 2008, 12:05 AM   #16
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Check out this guy for heatsinks too. These are new and he will cut them to any length needed.

http://cgi.ebay.com/HEATSINK-ALUMINU...QQcmdZViewItem
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Old 4th April 2008, 12:24 AM   #17
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http://www.firstwatt.com/downloads/F...-manual-sm.pdf
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Old 4th April 2008, 12:33 AM   #18
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I have been going over that a lot. Is there something in particular that you want to say about it?
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Old 4th April 2008, 12:49 AM   #19
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Hey Marsfrogie, the 2x 18v to 46v happens like this:

2x18v = 36v. This is the rms value of the transformer ac out wired in series.

36v * 1.414 (sq rt of 2) is the peak voltage you will get at the output of the power supply after the bridge rectifier and filter caps. This is actually around 50v. But after some various other losses in the diodes, etc. it will come out around 46vdc after filtering and before any regulation in the circuit. I'm not that familiar with the F3 circuit.

Peace,

Dave
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Old 4th April 2008, 12:52 AM   #20
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Thanks!
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