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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?

Be nice to animals.
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Old 27th April 2003, 08:26 PM   #3
Freddie is offline Freddie  Sweden
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Schematic can be found here:


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.

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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:

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
It's only audio. Member of the non modular PCB design committee
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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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