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Old 27th April 2003, 07:18 PM   #1
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Default Modifying DoZ Preamp to unity gain

I am interested in pursuing this preamp because the boards are avaialve and it seems to be a good, well respected design, but what I dont need is a gain boost in the preamp stage since I am not running the DoZ amplifier.

The key here is to keep the same board.

Thank you,

Paul Hilgeman
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Old 27th April 2003, 07:28 PM   #2
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Hi Paul,

Where can I find the schematic of this DoZ?

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Old 27th April 2003, 08:26 PM   #3
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Audiofanatic,

Schematic can be found here:
http://sound.westhost.com/project37.htm

PaulHilgeman,

R5 (22k) and R4 (10k) set the gain.
Increase the value of R4 to decrease gain.

Gain = (R5 + R4 ) / R4 = (22000 + 10000) / 10000 = 3,2
20 * log 3,2 = 10,1 dB

So the gain is 3,2 (10,1 dB).
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Old 27th April 2003, 09:47 PM   #4
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Thanks much, that is exactly what I needed.

-Paul
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Old 27th April 2003, 10:01 PM   #5
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Rod himself wrote this a few lines below the schematic:

Quote:
The gain is nominally 3.2 (10dB) as shown, and is easily changed by varying R4 - increase the value to decrease gain and vice versa.
Which goes to show that whatever someone writes people don't read it anyhow
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Old 28th April 2003, 12:28 AM   #6
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Thanks for pointing that out. I did read the entire thing one time, but it was about a year ago, then when it popped into my head and realized that I had to adjust the gain, I had forgotten.

Thanks though.

-Paul Hilgeman
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