looking for a mono amp kit

[davidbball13]

i found two mono amp kits which i would be using for my ipod or something. i just want to know what one is better and if any of you have built them.

https://www.allelectronics.com/cgi-bin/item/MK-1803/305/UNIVERSAL_MONO_PRE-AMPLIFIER_KIT_.html


and the ........
https://www.allelectronics.com/cgi-bin/item/MK-4001/305/7_WATT_MONO_AMPLIFIER_KIT_.html

 

[whiz115]

with $15 you buy amplified speakers for a PC..

 

[Leftyretro]

i found two mono amp kits which i would be using for my ipod or something. i just want to know what one is better and if any of you have built them.

https://www.allelectronics.com/cgi-bin/item/MK-1803/305/UNIVERSAL_MONO_PRE-AMPLIFIER_KIT_.html


and the ........
https://www.allelectronics.com/cgi-bin/item/MK-4001/305/7_WATT_MONO_AMPLIFIER_KIT_.html

I built the second one. I was real happy with it's performance, no noise or hum, lots of gain and easy to assemble.

Good luck
Lefty

 

[audioguru]

The first one is a pre-amplifier that amplifies a microphone then the pre-amplifier drives a power amplifier. It is not needed if an ipod feeds the power amplifier directly.

The second one is a 2W or 4W power amplifier that drives a speaker. It will have the max volume of a little clock radio.

 

[davidbball13]

yeah i think i will get the second one. i will be driving a computer speaker that is about 2'' in diemater and maby some 150 ohm one inch speakers i dont know about it.

 

[davidbball13]

I built the second one. I was real happy with it's performance, no noise or hum, lots of gain and easy to assemble.

Good luck
Lefty

i am assuming it is easy to build?
what kind of input are you using does it work well with a one eighth inch cord going into a cd player or ipod?

 

[davidbball13]

also what about using a 9volt battery. i want to put this in an altiods tin with it so it would have to be small

 

[audioguru]

Look at the datasheet fot the TDA2003 IC. Its minimum supply voltage is 8V then it operates poorly.
Look at the datasheet of a 9V alkaline battery. Its voltage quickly (15 minutes?) drops below 8V when it has a load of about 100mA.

The TDA2003 produces an output power of only 1.3W into a 4 ohm speaker with a brand new 9V battery. Its output into an 8 ohm speaker will be only about 0.7W.

Use a TDA2822 IC instead. It is small, works when its supply voltage drops down to 3V and costs only $1.56US at Digikey today. They have more than 1000 of them in stock.
Its output to an 8 ohm speaker is 2.6W with a brand new 9V battery.
Its idle current is 6 times less than the high idle current of the TDA2003.
A pcb design is in its datasheet. Somebody might make a kit with it.

 

[Leftyretro]

i am assuming it is easy to build?
what kind of input are you using does it work well with a one eighth inch cord going into a cd player or ipod?

Yes, as long as you know how to solder it's a simple quick build. You have to watch that you install the caps with the correct polarity It has plenty of gain and will work well with line level audio that is used by CD and ipod players. Be sure to first start with the volume turned down pretty low as the amp does have plenty of gain as I said. What I liked best about this simple amp was the proper sized heat sink they supplied, many other simple kits kind of skimp on that part.

Lefty

 

[audioguru]

I missed you saying that your speakers are only 1" and 2"?
They will just make little squeaks for sound. No bass.

 

[davidbball13]

Look at the datasheet fot the TDA2003 IC. Its minimum supply voltage is 8V then it operates poorly.
Look at the datasheet of a 9V alkaline battery. Its voltage quickly (15 minutes?) drops below 8V when it has a load of about 100mA.

The TDA2003 produces an output power of only 1.3W into a 4 ohm speaker with a brand new 9V battery. Its output into an 8 ohm speaker will be only about 0.7W.

Use a TDA2822 IC instead. It is small, works when its supply voltage drops down to 3V and costs only $1.56US at Digikey today. They have more than 1000 of them in stock.
Its output to an 8 ohm speaker is 2.6W with a brand new 9V battery.
Its idle current is 6 times less than the high idle current of the TDA2003.
A pcb design is in its datasheet. Somebody might make a kit with it.

jigga what? what what could i use as a battery

 

[audioguru]

The TDA2003 amplifier IC is designed to drive a 2 ohm or 4 ohm car speaker from a 12V car battery.

For your dinky little "speakers" you might as well use a dinky little TDA2822 amplifier which works much better with a reasonably low supply voltage.

Most little amplifiers built in a candy box use an LM386 little amplifier IC. With a 9V battery the output power is 0.45W into 8 ohms.

 

[davidbball13]

i have had a lot of bad luck with the LM386 i want to use it but i have had a bad experence with it do you have some good schematics for it

 

[audioguru]

The schematics in the datasheet of the LM386 work very well.
They assume that you are using a supply bypass capacitor that is required for all electronic circuits.
This schematic includes everything that is needed:

 

[davidbball13]

ok i think i will use that insted i will go to radio shack to get some parts i just need a few caps and what not. any advise for making the circuit

 

[audioguru]

ok i think i will use that insted i will go to radio shack to get some parts i just need a few caps and what not. any advise for making the circuit

Like most power amplifier ICs, the LM386 has a wideband frequency response to 300kHz. So it will probably oscillate and not work properly if it is made on a breadboard.

Keep the input wires away from the output wires.

 

[davidbball13]

what do you meen will it be distorted i have made one on a breadboard before and it was distorted. i will in the future put it on a perf board or a PCB

 

[audioguru]

A power amplifier that oscillates will sound distorted, or not work. It will probably get hot.

Any amplifier creates severe distortion if its volume is turned up higher than its max output power allows. The LM386 has a low output power so if you turn up the volume to be louder than low volume then it will create severe distortion.

 

[davidbball13]

is there an alternative to it. i need it to be kind of loud and not too distorted
convince over quality

 

[audioguru]

When it is louder then the battery is huge and heavy if you want the battery to last.

Many years ago (before ghetto blasters) I made some speakers and an amp for the beach. My beach sound system used 6 AA Ni-Cad battery cells and two bridged amplifier ICs producing 3.2W each into the 3" 8 ohm stereo speakers. Then I had a sub-woofer that used 6 C Ni-Cad battery cells and another bridged amplifier IC and it produced 6W into the 4" 4 ohms sub-woofer.
I had the best sounding sound system at the beach.

You must determine how much power you want.