I'm an electronics noob (and beginner at guitar). Although I have a Marshall CODE50 - an SS combo amp with amazing abilities to emulate a lot of Marshall products from the past - I want something that is lighter and not so loud sometimes. I've decided to stick my toe in with a simple LM386 amp.
I can read simple schematics (5 years of shop in HS) and find soldering easy enough (having learned to do O/A & electric arc welding in HS). I have tried several very simple LM386 designs with no success, using a 9V battery supply or 12 DCV power supply from a Sony BlueRay/DVD player. My most recent attempt used this version - https://www.instructables.com/id/Know-Your-IC-LM386/ - because it is the first I have found with detailed wiring of the 10K linear pot used for volume. However, I get absolutely no sound from any version tried; not even a buzz, hum, snap, crackle, pop. I'll stick to the latest version for this post.
The details are shown in the attached photos. This thing is very simple. Apart from the 10K linear volume pot and the mono 1/4" jack for the guitar plug, it uses only an NTE823 chip (apparently identical to an LM386), a 220uF 50V cap, a 0.047uF 100V cap, and a 10ohm 1/4W resistor. The speaker is 8ohm 1/2W.
When I use my MM to test voltage, the numbers are all over the place and usually drop to zero after a split second. I have to take the leads off and wait a bit before getting significant numbers. My guess is that I'm discharging a cap or 2 when I touch + and ground, but that's just a guess. Two things that I know for sure are that (1) with the pot "ON" all the way, I see varying measurements of 5V, 8V, 10+V, etc. measured on the back leg of the 220uF cap, promptly dropping to zero; and (2) with the pot "OFF" all the way, I see about 0.050V, constant, measured on the back leg of the 220uF cap.
I have been trying to get amp sound out of my Les Paul electric, which has passive pickups in parallel and uses a 9V battery to deliver a 15db boost with one of the knobs pulled up. I have also added a Danelectro Billionaire (Texas Trouble) stompbox using a 9V wallwart. I hear a volume increase on my Marshall when I use the 15db boost and also when I use the stompbox. Even using both with the breadboard, I hear absolutely nothing come from the speaker. The MM readings in the preceding paragraph are taken with both the 15db boost and the stompbox ON. One of the attached photos shows the stompbox, FWIW.
The pin layout of the NTE823 and LM386 are the same. The NTE823 specs are attached.
Any help would be greatly appreciated.
Jim
I can read simple schematics (5 years of shop in HS) and find soldering easy enough (having learned to do O/A & electric arc welding in HS). I have tried several very simple LM386 designs with no success, using a 9V battery supply or 12 DCV power supply from a Sony BlueRay/DVD player. My most recent attempt used this version - https://www.instructables.com/id/Know-Your-IC-LM386/ - because it is the first I have found with detailed wiring of the 10K linear pot used for volume. However, I get absolutely no sound from any version tried; not even a buzz, hum, snap, crackle, pop. I'll stick to the latest version for this post.
The details are shown in the attached photos. This thing is very simple. Apart from the 10K linear volume pot and the mono 1/4" jack for the guitar plug, it uses only an NTE823 chip (apparently identical to an LM386), a 220uF 50V cap, a 0.047uF 100V cap, and a 10ohm 1/4W resistor. The speaker is 8ohm 1/2W.
When I use my MM to test voltage, the numbers are all over the place and usually drop to zero after a split second. I have to take the leads off and wait a bit before getting significant numbers. My guess is that I'm discharging a cap or 2 when I touch + and ground, but that's just a guess. Two things that I know for sure are that (1) with the pot "ON" all the way, I see varying measurements of 5V, 8V, 10+V, etc. measured on the back leg of the 220uF cap, promptly dropping to zero; and (2) with the pot "OFF" all the way, I see about 0.050V, constant, measured on the back leg of the 220uF cap.
I have been trying to get amp sound out of my Les Paul electric, which has passive pickups in parallel and uses a 9V battery to deliver a 15db boost with one of the knobs pulled up. I have also added a Danelectro Billionaire (Texas Trouble) stompbox using a 9V wallwart. I hear a volume increase on my Marshall when I use the 15db boost and also when I use the stompbox. Even using both with the breadboard, I hear absolutely nothing come from the speaker. The MM readings in the preceding paragraph are taken with both the 15db boost and the stompbox ON. One of the attached photos shows the stompbox, FWIW.
The pin layout of the NTE823 and LM386 are the same. The NTE823 specs are attached.
Any help would be greatly appreciated.
Jim
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