Replies to This Discussion

Permalink Reply by Douglas Eric Marsalis on August 30, 2010 at 6:38pm

Thanks Nazzy. I have been searching for the last 2 hours on-line looking for some instructions. Everything that I run across requires money. I was hoping to get some help from the Nation before sinking anymore money. I am totally ignorant on electronics unfortunately. I know once I build ONE that works, I will be OK. I really appreciate your help.

I joined the LED wiring between the switch and the battery. So you think that the LED will burn out quickly? I will give your diagram a go later on. Thanks again.

Douglas

• ▶ Reply

Permalink Reply by Douglas Eric Marsalis on August 30, 2010 at 6:53pm

Nazzy, the NO JOIN HERE wire is just connected to the board and not connected to anything else? OR connected to the battery power supply?

D

• ▶ Reply

Permalink Reply by Wes "I'm Baaaaack" Yates on August 30, 2010 at 11:45pm

So Naz is spot on. Follow his LED... I mean lead.

One thing you can consider is (in addition to the trim on the left) is put a volume on the + lead of the speaker connection leaving the trip to handle any overload from the input. This will be confusing but you can buy a small pot with an on/off switch which will work well. Make a ground lead from the pot body to (-) on the board too. If there are three leads on a volume pot, I use (1) for input, (2) for output and (3) I solder to the body as ground.

If you want the LED, put it in the + lead of the Power/Battery but note, LEDs are polar. That is they are supposed to be in a certain direction (they have a + and - side). If I remember, the longer lead side is the (+) or there is a flat side (-). Make sure you have that in right OR the light (and perhaps the power) won't work.

-WY

• ▶ Reply

Permalink Reply by Dave Onastik on August 31, 2010 at 12:42am

Not trying to put down the Champ Amp. I'm sure it will work just fine, but wanted to share a recent purchase on ebay:

http://cgi.ebay.com/Low-Voltage-Audio-Amplifier-Module-Based-NJM386...

For $8.50 shipped (from Hong Kong) the board came assembled as shown in the picture. It uses the same LM386 Amplifier as the Champ, and includes a volume pot with an on/off switch. All you need to do is add the speaker, power supply (9V battery) and input jack, like Nazzy showed you above. The nice thing is that this board has screw terminals, so you don't have to solder on the board.

Also, you can add an LED, but Nazzy is right about the resistor. Radio Shack sells LED assemblies that have a resistor build in for $2:
http://www.radioshack.com/product/index.jsp?productId=2062569

I love doing soldering/board level projects, but as my eyesight deteriorates with age, I find myself looking to for the easy way out.

• ▶ Reply

Permalink Reply by Douglas Eric Marsalis on August 31, 2010 at 12:50am

Never mind. I got it.

D

Douglas Eric Marsalis said:

Nazzy, the NO JOIN HERE wire is just connected to the board and not connected to anything else? OR connected to the battery power supply?

D

• ▶ Reply

Permalink Reply by petey twofinger on August 31, 2010 at 10:38am

if you want to save some money and a trip to rat shack just look up resistor color band chart , dig around on some junk electronics for the resistor and led . a one ohm resistor should work . i blew up some led's in my day , and fried the powering section on an amp board just wiring em straight up . an easy way to determine polarity on n led is with a button battery , nothing happends if you hook it up wrong . stock new , the long lead is the positive .

it would seem to me , if i was gonna order an amp kit online i would find one that has a little more wattage though . they have em cheep , dont they ? like 8.50 for a 5 watt or something . maybe go with some C cells , and an ac adapter for inside , , , bu thats just me .

• ▶ Reply

Permalink Reply by sodbrother on September 20, 2010 at 3:49pm

Dave, I just bought a NJM386 like you were talking about from eBay. 2 questions: What do you power it with (9v battery?)? And what size speaker (what or how many ohm)?

Dave Onastik said:

Not trying to put down the Champ Amp. I'm sure it will work just fine, but wanted to share a recent purchase on ebay:

http://cgi.ebay.com/Low-Voltage-Audio-Amplifier-Module-Based-NJM386...

For $8.50 shipped (from Hong Kong) the board came assembled as shown in the picture. It uses the same LM386 Amplifier as the Champ, and includes a volume pot with an on/off switch. All you need to do is add the speaker, power supply (9V battery) and input jack, like Nazzy showed you above. The nice thing is that this board has screw terminals, so you don't have to solder on the board.

Also, you can add an LED, but Nazzy is right about the resistor. Radio Shack sells LED assemblies that have a resistor build in for $2:
http://www.radioshack.com/product/index.jsp?productId=2062569

I love doing soldering/board level projects, but as my eyesight deteriorates with age, I find myself looking to for the easy way out.

• ▶ Reply

Permalink Reply by Rand Moore on September 21, 2010 at 1:28am

Hi Sod Brother.

That pre-assembled amp on E-Bay interested me, so I followed the URL and either there or thereabouts, I scrolled down the page and came to a scematic and then some more board specs.

The operating power for this amplifier can range from 4 VDC to 12 VDC, with 9VDC being a common option. A 9VDC transistor radio style battery should do the trick.

I did not see a spec on the speaker rating, but the R1 resistor on the output side of the Op Amp is 10 ohms, so it should work with any 8 ohm speaker.

Hope this helps.

-Rand.

sodbrother said:

Dave, I just bought a NJM386 like you were talking about from eBay. 2 questions: What do you power it with (9v battery?)? And what size speaker (what or how many ohm)?
Dave Onastik said:

Not trying to put down the Champ Amp. I'm sure it will work just fine, but wanted to share a recent purchase on ebay:

http://cgi.ebay.com/Low-Voltage-Audio-Amplifier-Module-Based-NJM386...

For $8.50 shipped (from Hong Kong) the board came assembled as shown in the picture. It uses the same LM386 Amplifier as the Champ, and includes a volume pot with an on/off switch. All you need to do is add the speaker, power supply (9V battery) and input jack, like Nazzy showed you above. The nice thing is that this board has screw terminals, so you don't have to solder on the board.

Also, you can add an LED, but Nazzy is right about the resistor. Radio Shack sells LED assemblies that have a resistor build in for $2:
http://www.radioshack.com/product/index.jsp?productId=2062569

I love doing soldering/board level projects, but as my eyesight deteriorates with age, I find myself looking to for the easy way out.

• ▶ Reply

Permalink Reply by Mungo Park on September 21, 2010 at 4:45am

What a timely post, I ordered 2 of those little Dodahas. I have been looking around at these AMp "kits" for a while now, this one fit the budget and my skill level. I was just collecting up the parts up, and looking around for a 9 volt battery clip on treminal thingie, I must have one around I cam rip off one of the kids old toys. I have not got any further. I have a 4" speaker that should fit the bill.
I will post some photos once things come together. Cheers Ron.

• ▶ Reply

Permalink Reply by sodbrother on September 21, 2010 at 2:31pm

Thanks Rand! I will post pics when i'm done, but it might be a while. I've got a bunch of guitars I need to wrap up first.
Thanks Again!!!

Rand Moore said:

Hi Sod Brother.

That pre-assembled amp on E-Bay interested me, so I followed the URL and either there or thereabouts, I scrolled down the page and came to a scematic and then some more board specs.

The operating power for this amplifier can range from 4 VDC to 12 VDC, with 9VDC being a common option. A 9VDC transistor radio style battery should do the trick.

I did not see a spec on the speaker rating, but the R1 resistor on the output side of the Op Amp is 10 ohms, so it should work with any 8 ohm speaker.

Hope this helps.

-Rand.

sodbrother said:

Dave, I just bought a NJM386 like you were talking about from eBay. 2 questions: What do you power it with (9v battery?)? And what size speaker (what or how many ohm)?
Dave Onastik said:

Not trying to put down the Champ Amp. I'm sure it will work just fine, but wanted to share a recent purchase on ebay:

http://cgi.ebay.com/Low-Voltage-Audio-Amplifier-Module-Based-NJM386...

For $8.50 shipped (from Hong Kong) the board came assembled as shown in the picture. It uses the same LM386 Amplifier as the Champ, and includes a volume pot with an on/off switch. All you need to do is add the speaker, power supply (9V battery) and input jack, like Nazzy showed you above. The nice thing is that this board has screw terminals, so you don't have to solder on the board.

Also, you can add an LED, but Nazzy is right about the resistor. Radio Shack sells LED assemblies that have a resistor build in for $2:
http://www.radioshack.com/product/index.jsp?productId=2062569

I love doing soldering/board level projects, but as my eyesight deteriorates with age, I find myself looking to for the easy way out.

• ▶ Reply

Permalink Reply by Mister Scott on September 22, 2010 at 12:39pm

If one wanted to use a DC power source instead of the 9v battery, what's the best option? Are there premade plug terminals that can be soldered to the circuit board?

• ▶ Reply

Permalink Reply by Mister Scott on September 22, 2010 at 2:12pm

Another question (sorry, don't mean to hijack the post)... Some 8 ohm speakers I've been looking at have nominal input power rates of 5 watts or so. Will a 1.5/2 watt amp work with these speakers?

Rand Moore said:

I did not see a spec on the speaker rating, but the R1 resistor on the output side of the Op Amp is 10 ohms, so it should work with any 8 ohm speaker.

• ▶ Reply