mccpe
22-Sep-10, 11:11
I have spent some time looking at various threads on the forum, but I'm not certain that I have found the right answers yet - sorry if this repeats earlier questions!
I want to build a portable instrument PA for a clasical guitar, used for busking and recitals in small venues - chapels and the like. Unlike most guitar amps, this needs to be a clean amp, more like a keyboard or vocal amp. As I want to use it on battery power, a silicon amp seems like a better bet than a valve amp. I'm pretty competent with a soldering iron and experienced with digital electronics, but audio amps are pretty new to me.
So, to start with, I was inspired by this amplifier (http://www.runoffgroove.com/macruby.html) which is a simple LM386 in a old Mac Plus case. I have an old Mac Plus from the 80s and even an original Apple Mac carry case, so I'm going to go for this as a cabinet.
The Mac, usefully has its own SMPS that provides an adequate 12V supply. I figured that I would use a 12V SLA battery, with a simple charging circuit so that I can run off battery or mains supply.
The guitar has a high impedance pickup which will need a suitable preamp. I then need a mono power amp and I have been thinking of using something like this JBL car speaker (http://www.jbl.com/EN-GB/Products/Pages/ProductDetails.aspx?PID=GTO8628&accT=1&tsT=0&ovT=1). The speaker should fit, and is about as efficient as I can find, plus the coax tweeter should give me a better sound than trying for a full-range speaker that may fit.
So my questions:
1. Which 41hz amp kit to use?
2. If the recommended amp kit requires more than +12v, ideas on how to derive the supply from 12v?
3. Are SLA batteries a good choice? I see quite a lot about LiPo baterries on 41hz, but I'm assuming they need a bespoke charger?
4. Any ideas for a preamp? I only need gain and a simple tone stack.
Thanks,
Paul.
I want to build a portable instrument PA for a clasical guitar, used for busking and recitals in small venues - chapels and the like. Unlike most guitar amps, this needs to be a clean amp, more like a keyboard or vocal amp. As I want to use it on battery power, a silicon amp seems like a better bet than a valve amp. I'm pretty competent with a soldering iron and experienced with digital electronics, but audio amps are pretty new to me.
So, to start with, I was inspired by this amplifier (http://www.runoffgroove.com/macruby.html) which is a simple LM386 in a old Mac Plus case. I have an old Mac Plus from the 80s and even an original Apple Mac carry case, so I'm going to go for this as a cabinet.
The Mac, usefully has its own SMPS that provides an adequate 12V supply. I figured that I would use a 12V SLA battery, with a simple charging circuit so that I can run off battery or mains supply.
The guitar has a high impedance pickup which will need a suitable preamp. I then need a mono power amp and I have been thinking of using something like this JBL car speaker (http://www.jbl.com/EN-GB/Products/Pages/ProductDetails.aspx?PID=GTO8628&accT=1&tsT=0&ovT=1). The speaker should fit, and is about as efficient as I can find, plus the coax tweeter should give me a better sound than trying for a full-range speaker that may fit.
So my questions:
1. Which 41hz amp kit to use?
2. If the recommended amp kit requires more than +12v, ideas on how to derive the supply from 12v?
3. Are SLA batteries a good choice? I see quite a lot about LiPo baterries on 41hz, but I'm assuming they need a bespoke charger?
4. Any ideas for a preamp? I only need gain and a simple tone stack.
Thanks,
Paul.