I'm building a Combo Amp for someone.

The cabinet is Pine 13" wide x 15" tall and 11" deep. All glued together and used a 1/2" roundover bit in my router for the edges.

The speaker is a vintage 10" Utah 15W 8ohm. The amp is my dual Im386 chip bridged amp design. Can run on 9volt battery or walwart and output is 1 to 2 watts.

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" In local news, a number of residents claim they heard profanities coming from a neighbor's house. One person also claimed to have seen a cat flying out of a window of that house".

Like one of those Loony Tunes when you see a cat flying through the air with it's behind arched higher that it's body and a kicking foot behind it.

It was tempting, but I don't do that to animals even if they make me want to sometimes. LOL

The wife did ask what was wrong from a couple rooms over and mentioned something about language.

Yes, but clear packing tape would be better. It's stickier and tends to split when you try to take it off. LOL

It's repairable.

Speaker has shipped. The anticipation builds.  A cat is seen wandering around meowing waiting for another speaker to trash.

Speaker arrived.

Yes it was fast, but it didn't have to travel far. They are located in Paducah, KY.

Dang Gremlins. I got the speaker in and now the amp starts acting up. There's way too much noise in this amp and I think it's because the components are too close together on the board. So I've taken the board out, removed all the components and started over with some space between the components.

Also, I'm going to have to go back to 1 input because it's just causing to many problems with the chips. I'm also going back to 1 volume pot controlling both chips because both end up all the way out anyway so I'll need to make another control board.

Basically I'm reverting back to the original design that I did when I made mine because it worked without issues. It will have a switchable cap choice on the input channel, but only be able to use one thing at a time on this amp.

I'm thinking that isolation diodes in the output circuit would be needed to keep signal from creeping into the other board.

The problem I'm having is that both circuit's Jfets end up being tied together in the power section and they are too close together. So I just have to go back to a known good circuit.

Step away from the duct tape. Haha

So I rewired the board and made a new control plate.

It seems that the IM386N1 chips are bad. I've used the N1 on Ruby amps without issue and they were available locally at Radioshack, My original dual chip amp that I built suffered damage from power polarity reversal, but this build should still be working since there wasn't an issue with reversed power polarity. I'm beginning to believe that the N1 chip isn't well suited to this dual chip amp. 

In a couple of weeks I'm going to order some N3 chips and give them a try. Hopefully they will be better than the N1's.

So true, I have had a few of a batch of IC chips test bad/not work properly.

Might be the right choice to get the N3's, simply for the higher output (700mW per IC for the N3 versus 325mW for the N1).

Hope it works for you.

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