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Old 28th September 2006, 12:09 AM   #1
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Default Passive Pre-Amp causes huge power loss?

I built a passive preamp for my old tube amp using only the proper connectors and a pot. The problem is that I lose over half of the volume even when fully torqued?

I did connect all of the grounds together at the pot ground...Is this wrong? The grounding was my only confusion...but it plays?

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Dominick
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Old 28th September 2006, 12:27 AM   #2
Enzo is offline Enzo  United States
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What value is the pot? Is it wired right to a grid?

I doubt the grounding is an issue, you are loading the signal down.
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Old 28th September 2006, 12:29 AM   #3
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Grid?

It isnt wired to anything. I tried both a 100k pot and a 10k pot.
Same results.

Also, as I turn the pot, the volume goes up and then back down as I continue turning.

Dominick
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Old 28th September 2006, 12:58 AM   #4
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Please include your schematic.
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Old 28th September 2006, 01:30 AM   #5
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Here is a rough sketch!

Dominick

Click the image to open in full size.
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Old 28th September 2006, 01:38 AM   #6
aerius is offline aerius  Canada
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Quote:
Originally posted by Dominick22
Also, as I turn the pot, the volume goes up and then back down as I continue turning.

Dominick
That's odd...is it possible you got a balance pot by accident instead of an audio taper pot? If the volume starts going back down once you hit the halfway point on the pot's rotation, chances are you got a balance pot.
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Old 28th September 2006, 01:40 AM   #7
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Your connection is not correct, the center pin should be out, not ground.
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Old 28th September 2006, 01:52 AM   #8
Tuukka is offline Tuukka  Finland
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try this
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File Type: jpg volume.jpg (7.4 KB, 165 views)
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Old 28th September 2006, 02:02 AM   #9
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Peter and Tuukka,


LOL,
Sometimes I overlook the smallest things and stump myself. Problem fixed. Thanks so much...Now I can tone it down for the neighbors!


Dominick
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Old 28th September 2006, 10:34 AM   #10
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As stated above.. when looking at the back of any pot the ground is on the left, out the center, and input on the right.

That is when you face the tabs up.
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