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Started by guitarman1, July 28, 2013, 08:56:18 PM

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guitarman1

hi sorry to be a pain i was told by a music shop i got to have a special amp or a pa for a acoustic guitar would that be right also can i make one

J M Fahey

Maybe you can, if you have some building practice, can read a schematic and a multimeter, and can follow instructions.

You'll also need to know how to make PCBs , although you can skip that by using kits, such as Velleman's or similar.

Look at Vellemans catalog, browse their small power amp kits (between 1 and 15/25W), download the build instructions.

Build one.

If you succeed, you have run 50% of the path, with good possibilitoes of tunning to the end.

QReuCk

In my experience, you can pretty well use an electric guitar amp for amplifying an accoustic, but you'll have to deal with some issues:
1° Electric guitar amps are designed to reproduce well frequencies up to 6KHz. Higher frequencies are highly disregarded in this context. For a metal stringed accoustic, you need up to 12 KHz if you want to hear all the complexity of the harmonics. That's more caused by the speakers than the amp itself, but amps are designed knowing that they won't have to reproduce frequencies higher than 6KHz, and some designer like to purposedly restrain the range in order to give an easier job for the amp. If you have a nylon stringed accoustic, you will barely hear this limitation.
2° Usually, Accoustic amps have a pretty usefull feature to control feedback and prevent it being turned into larsen. These are phase inversion switches or specific narrow Q band-cut filters to cut the larsen frequency. You won't have that on an electric guitar amp. Knowing how to position yourself and your guitar in relation to the speakers and/or inserting an multiband EQ (or parametric if you find one) in your chain can go a long way to not need these features, but these are workarounds.

I personaly use my Peavey Envoy110 when playing my nylon and I am very happy with it. It sure isn't a perfect solution, but it's what I've been using for a few years now and I even had compliments about how "real" it sounded.
I had one of my friend playing through it with is folk electro accoustic and found it didn't sound bad at all. Maybe not all of the chiming top end, but still good enough to not be ashamed playing for an audiance.

You have to remember that a lot of commercially available SS amps for electric guitar are just a power amp and a very transparent preamp (at least for their clean chanels).

But if you want to build something, listen to other guys here, they are super knowledgeable, which I am not. I just like lurking here to learn one thing or two from them and share my very little experience when I think I can help.

Roly

Quote from: QReuCkprevent it being turned into larsen.

"Larsen"?   ???   Being an Aussie and not Danish this was a new one on me so I had to look it up, and sure enough we non-Danes can read this as "audio feedback" a.k.a. "Howl-around".

Quite agree with all the comments and would paraphrase by saying that amps intended for acoustic guitar tend to be rather more "Hi-Fi" than your typical guitar amp, wider bandwidth and less distortion and perhaps better EQ available, and that typical PA rigs go in that direction.

Many acoustic guitars these days come with in-built phase inversion switches, small graphic EQ's* &c, and these may be sufficient to get you going.  All you then need is some reasonable power amplification and a fairly wide range cab or two.  Just about any chip amp will have wide enough frequency response to do the job, just pick your power level, but your speaker(s) will require a bit of care to get a wide-ish bandwidth (however there is no need to go bat-crazy like the Hyper-Fi's, just some good top end).

{* I normally consider graphic EQ's to be an audio abomination, an instrument of the devil and plaything of the clueless, but this is an example of where a (cheep cheep second hand home stereo) graphic EQ, the more bands the better, can actually be of good use.  Parametric EQ is however still better IMO.}

If you say theory and practice don't agree you haven't applied enough theory.

guitarman1

Quote from: QReuCk on July 31, 2013, 09:41:24 AM
In my experience, you can pretty well use an electric guitar amp for amplifying an accoustic, but you'll have to deal with some issues:
1° Electric guitar amps are designed to reproduce well frequencies up to 6KHz. Higher frequencies are highly disregarded in this context. For a metal stringed accoustic, you need up to 12 KHz if you want to hear all the complexity of the harmonics. That's more caused by the speakers than the amp itself, but amps are designed knowing that they won't have to reproduce frequencies higher than 6KHz, and some designer like to purposedly restrain the range in order to give an easier job for the amp. If you have a nylon stringed accoustic, you will barely hear this limitation.
2° Usually, Accoustic amps have a pretty usefull feature to control feedback and prevent it being turned into larsen. These are phase inversion switches or specific narrow Q band-cut filters to cut the larsen frequency. You won't have that on an electric guitar amp. Knowing how to position yourself and your guitar in relation to the speakers and/or inserting an multiband EQ (or parametric if you find one) in your chain can go a long way to not need these features, but these are workarounds.

I personaly use my Peavey Envoy110 when playing my nylon and I am very happy with it. It sure isn't a perfect solution, but it's what I've been using for a few years now and I even had compliments about how "real" it sounded.
I had one of my friend playing through it with is folk electro accoustic and found it didn't sound bad at all. Maybe not all of the chiming top end, but still good enough to not be ashamed playing for an audiance.

You have to remember that a lot of commercially available SS amps for electric guitar are just a power amp and a very transparent preamp (at least for their clean chanels).

But if you want to build something, listen to other guys here, they are super knowledgeable, which I am not. I just like lurking here to learn one thing or two from them and share my very little experience when I think I can help.
i have a fender its has a pick up has battery it has eq bass trebi forget the other it is acoustic guitar steel strings not nylon