Tone control - passive vs. active?

[lion]

I'm planning to build a preamp/EQ for my acoustic guitar. Apart from the loss in passive networks (which can be easily compensated)- are there any pros and cons soundwise.

For a sweepable mid control and notchfilter I obviously have to go active, but I'm wondering about the LF and HF controls.

What's the general opinion?

lion

[onboard]

I prefer passive so you don't need a power supply. Abusing tone boost is too easy. From a sound engineer's point of view, it's always better to cut. Obviously, preamping an acoustic requires going active.

Would boosters be active volume controls? And tone too, I suppose, if the circuit's not transparent.

What design are you looking at, or are you drawing your own? I would like to build a transducer preamp that would be nice for banjo.

Tough question, a custom bass builder's forum would eat that alive... :wink:

[lion]

Sorry - I can see that my post was poorly worded, and could be easily misunderstood.
As a preamp it's obvious it has to be active. It's the tonestack I was considering - passive, like in most tube amps - or active, build as seperate filters (bas/mid/treble/ect) around opamps.

This morning I found the schem of the Fender Acoustasonic - I think I'll go for a preamp very close to this. The Jr and the SFX has gain, bass. mid, treble and a sweepable notch and 'string dynamics' (6,3 kHz cut).

lion

[Mike Burgundy]

I prefer parametrics for acoustic, perhaps two sweepable bands (switchable Q is nice) with a separate shelving bass/treble.
This usually is enough for soundshaping and all but the worst feedback problems.
hih
PS where's that acoustasonic pre? I'd like a peek as well

[lion]

Mike - I know what you mean about the parametrics, but the Acoustasonics looks interesting - should be relatively simple to build the preamp/EQ sections.
You can find the schem in pdf-format on the Fender support sides.

Why would you prefer the shelving bass/treble?
Erik

[Mike Burgundy]

I use the shelving B/T for basic shaping, and the parametric for battling feedback. I find that I usually set mid minimal on acoustic, so I leave that out as a control.
You could also go for more parametric bands.

[lion]

Mike - I understand. I was wondering about the shelving slope, seems to me that it would also amplifiy freq's outside the useable range - causing LFrumble/HFhiss problems - but maybe not?

lion