Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: jambre on April 26, 2006, 06:25:39 AM

Title: Acoustic Guitar Combo Amp-1st Project
Post by: jambre on April 26, 2006, 06:25:39 AM
I'm looking for a combo amp I can build for my acoustic-doesn't have to be spectacular, but I'd like to use a two-way (Woofer, Tweeter, and X-ver) speaker in the cab-I have some basic electronics knowledge, I can solder and I have access to woodworking equip, so I can build my own cabinet-Any suggestions?
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: RDV on April 26, 2006, 06:58:57 AM
Design and build your cabinet 1st I say. Just leave a good sized place for your electronics. A transformer needs some room as to not be too close to your other components. A good way to go for something like this would be to biamp. An example would be using an LM3886/LM1875 combo along with an active crossover.

RDV
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: joecool85 on April 26, 2006, 08:05:26 AM
Yeah, an lm3886 (50w) for the lows because they take more juice and the lm1875 (20w) for the highs.  How much power did you need/want?
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: jambre on April 26, 2006, 08:16:30 AM
As far as power goes, I'll be using the amp at home and church (...It was only driven by a little old acoustic to and from church...)-power isn't a priority, but I'd like clean sound-
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: RDV on April 26, 2006, 10:15:55 AM
For clean headroom, power is how you achieve it, but 70 true watts will make a nice acoustic amp with careful speaker choices.

RDV
Title: Re: Acoustic Guitar Combo Amp-1st Project-Questions
Post by: jambre on April 26, 2006, 02:38:46 PM
First, thanks for the replies-

Now for the questions:

1) Is there a schematic for the LM3886/LM1875 with the X-over, preamp, etc.?

This is great-

Jim B
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: joecool85 on April 26, 2006, 02:46:27 PM
The easiest way to do it would be to order PCB kits from Brian for both the lm3886 and lm1875 (the lm1875 is a prototype, but he will normally give them out anyway), as far as the preamp goes you could do a couple things including: build your own preamp, line out from an existing guitar amp, or buy a preamp like this:

http://www.musiciansfriend.com/product/Live/Sound/Signal/Processors?sku=182482
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: teemuk on April 26, 2006, 02:49:28 PM
One thing you should also consider is that acoustic amps are usually equipped with some kind of an "anti-feedbacking" circuit. Those hollow-body guitars tend to get really crazy when you stand too close to an amp - even at very low volumes.
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: RDV on April 26, 2006, 02:50:30 PM
That Behringer preamp would work well as an acoustic preamp as long as the guitar has a decent EQ built in. If not, a graphic EQ might work well.

RDV
Title: Re: Acoustic Guitar Combo Amp-1st Project
Post by: RDV on April 26, 2006, 02:52:08 PM
Quote from: teemuk on April 26, 2006, 02:49:28 PM
One thing you should also consider is that acoustic amps are usually equipped with some kind of an "anti-feedbacking" circuit. Those hollow-body guitars tend to get really crazy when you stand too close to an amp - even at very low volumes.
Not so bad with one of those rubber things in the soundhole. This is where a good graphic would shine. The more bands the better to pinpoint the FB frequency.

RDV