Small Combo Build

[Zepfan]

I'm building a small combo amp for someone. It's a SS Dual IM386 Chip Bridged Amp based on my schematic that was derived from the Ruby Amp and a dual chip pedal design. Overall output is 1 to 2watts at 8ohms. will run on a 9volt battery or walwart. Using a vintage Utah 10" speaker that I got at Goodwill for 5 bucks. Whoohoo.

Made the cabinet out of Pine. 15" tall x 13" wide x 11" deep. I burned the cab with a propane torch after sanding and routing the edges with a 1/2" roundover bit. Turns out my old torch had a leak and caught on fire while I was using it. Got the fire out and went to Tractor Supply and bought a new torch to finish the job.

 

[Zepfan]

I'm altering the schematic a bit. Instead of switching between the input caps(.047uf - .1uf) for regular operation or darker tone option, I'm installing 2 input jacks with separate caps(1 .047uf and 1 .1uf) for High/Low input choice and deleting the switch.

Pics of cab after burning with torch. Now adding Truoil.

 

[Mike_LA]

TUBES ! ! ! !
It needs tubes , , , , , , , ,

​

 

[mungus]

Wow what a beautiful finish

I was looking for more info and found this:

 

[Zepfan]

TUBES ! ! ! !
It needs tubes , , , , , , , ,

​

I generally prefer tubes myself, but this little amp is killer.

Wow what a beautiful finish

I was looking for more info and found this:

Thanks
A member here on the TDPRI did a beautiful torch finish on a Tele build and I just couldn't resist doing it to this cabinet.

 

[mungus]

I'm trying to figure out the process. Do you just scorch it lightly and you're done or give it a good burn then sand gently until the grain comes back out?

 

[Zepfan]

I just lightly burned with the torch and started adding Truoil. 2 coats so far. After 3 or 4 coats, I'll decide if I want it to remain glossy or if I want to scuff it with steel wool for a satin finish.

 

[mungus]

In the photos there's a really nice rippled effect as if you're looking through water dappled with sunlight. A deep gloss might help to bring that out.

It's really quite stunning. You could probably set yourself up making Shou Sugi Ban furniture. I bet that would sell really well in the right kind of market.

 

[Zepfan]

In the photos there's a really nice rippled effect as if you're looking through water dappled with sunlight. A deep gloss might help to bring that out.

It's really quite stunning. You could probably set yourself up making Shou Sugi Ban furniture. I bet that would sell really well in the right kind of market.

It might do well. Spent some time in the furniture/mattress making industry when I was young. It's a real cut throat business. Lots of companies go under with a couple years. You really have to follow the trends that can change at a moments notice or you'll be stuck with a lot of products that nobody's interested in. Guess the same can be said for musical merchandise.

 

[Zepfan]

Got the speaker mounted on the plywood baffle. Time to pic out the speaker cloth/grill. Thought about using a metal grill and was going to the hardware store when I pasted a Hancock Fabric store that was having a store closing sale. I picked up a yard each of two materials that I thought would look good. I'm leaning towards the blue since my first choice would have been blue denim.

 

[Greenstreet]

Looks great! I think the blue would be a better contrast with the cabinet-

 

[Zepfan]

Looks great! I think the blue would be a better contrast with the cabinet-

My thoughts too. The person I'm building this amp for picked the blue, so blue it will be.

 

[Zepfan]

I applied the Truoil by pouring some on and spreading it on with my finger like I've done on necks and small areas of CBG builds. Doesn't work well on large areas like a speaker cabinet though. Little bubbles all over and a stray hair from a cat or the dog.
I sanded down some with 400 grit sandpaper and started applying with a folded paper towel. One more coat should wrap it up.
The rear access door has been trimmed to fit and painted Black. Got some brass hinges for the door and a brass hook to keep it closed.
Need some tack strips to put the grill cloth on. Another trip to the store.

 

[Zepfan]

A pic of the circuit board. Have to add another Jfet and the input caps.

 

[Andy B]

The Ruby amp design is great. I have one for a battery powered amp & another that I made an Audio Signal Tracer out of it.

 

[BartS]

Looking great so far just don't stain any part of it pink.

 

[Zepfan]

The Ruby amp design is great. I have one for a battery powered amp & another that I made an Audio Signal Tracer out of it.

I agree, love the sound of the Ruby. This circuit just doubles the gain.

Looking great so far just don't stain any part of it pink.

Never been a big fan of that color, so no danger of that.
How did your build go? Finished?

 

[BartS]

I agree, love the sound of the Ruby. This circuit just doubles the gain.

Never been a big fan of that color, so no danger of that.
How did your build go? Finished?

I been real busy so it had to go on the back burners. I'm going to sand the whole amp down when I get the chance and redo the stain. I just can not live with that color on the amp. Sometimes Life gets in the way.

 

[Zepfan]

Life has a way of doing that.

Got the back door attached.

 

[BartS]

I like the door. Yeah I'll get back to it eventually I really I mean really like how the amp sounds. So I'll get to it sometime or another and finish it off making sure the cabinet is as nice as my cabinet building skills can be.