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amz mini booster as volume control

Started by 9Lives, May 18, 2012, 09:56:02 AM

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9Lives

I hate the way volume controls simply ground the signal. It often leaves unity gain set at max. Is this a good subsitue as a volume control? It seems like it would slightly boost the sig rather than ground it? This is a complete assumption.. Any thoughts or facts?

midwayfair

The AMZ is never below unity (it says in their build notes that it provides ~3db at minimum), and it always boosts the signal. If you feel a boost more signal, it doesn't cap the volume, it either boosts it or clips.

Basically, almost every volume control involves grounding signal or source. Since a pedal essentially has two sources (the 9v and the instrument), you do have a few options.

You could create a pre-gain stage that would reduce the amount of volume going *into* an effect from the instrument. But if you're looking to put it in a distortion circuit, that's going to severely compromise the amount of distortion you can get from most designs.

You could reduce the voltage the pedal is getting -- this will reduce the total output volume in overdrive pedals, which would let you run the volume full out. This could induce gating, so breadboarding will help eliminate bias issues.

You could, in extreme cases, create a compressor/limiter circuit on the tail end of the effect. Less compression will give you more volume, more compression will reduce the output. The Afterlife would actually be fairly good for this, because it's very transparent, involves very few parts, and the volume limiting is fairly severe on the highest settings. But ... the volume control in the afterlife also grounds the signal.

Can I ask what exactly you feel is lacking when you turn down the volume? Is it e.g. a lack of brightness? Because there are solutions to that problem in the form of treble bypasses. If it's a "just doesn't sound the same/as good" problem, you could be fighting the physics of sound.

9Lives

I just seems to me that grounding the final result of the circuit is.. I dunno. Hard to put it in words. It's basically just blending in the ground with the circuit. Am I right? I've noticed in some designs they will do this before a final op amp or transistor stage. I just notice on most OD or dist pedals I build I use the volume in the same place which doesn't seem to hurt anything BUT In the compressors I build (alot) when you turn the vol down any from MAX it degrades the result. You can touch the string with sustain maxed out and feel the compressor doing it's magic but as soon as you turn the vol down any it almost cancels out the affect. So what's the solution? I just wondered it using a boost of some sort at the end of a design would improve this issue.. Of mine atleast.