3/01/2013

c.1939 Oahu 230K Guitar Amplifier Project


This cute little tube amp is an Oahu-sold model 230K which went along with their front-line 229K lap steel. I have two of these but only one good cabinet so this amp is excess. I popped on a 3-prong cord with the "death cap" clipped to test it out and it powers up with all the tubes lighting but the output is very low and distorted through the Jensen 8" field coil speaker (4 prong lead to that).

I'm pretty sure this isn't just a "tube" issue and it'll likely need to be gone through and recapped. This amp will make someone a great project so I'm putting it up here as-is since I don't want to go through a second one.


The tube complement is curious and cool: 6N7-G, 6C5-G, 6N6-G, and something marked "80." Pilot lamp still functions (not burned out!) and the fuse is good. The two inputs are: #1 volume adjustable and #2 flat-out non-volume input like on the slightly earlier (and cheaper) incarnations of this amp.


As you can see, it's pretty clean inside.


Here's that Jensen 8" speaker rear.

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