Anybody ever heard of a "Stewart" guitar amp? [Pictures]- created 09-09-2008

Stewart, Rick - 09/09/2008.20:11:14

The reason I ask is because a friend of mine found a vintage looking Stewart SL-21 lying around in his studio and he thought that since my last name is Stewart I would like to have this amp. Well, I'm thrilled to add it to my family. But it doesn't work. Only one of the six tubes glows brightly, one tube doesn't glow at all. There is a red wire hanging loose from the channel two input jack.

It has a 12" speaker that says on the back,"Made Expressly for Olson by Jensen Manufacturing Company Made in USA".

It also has a hand drawn schematic on the inside of the back cover.

I called Stewart Electronics (the folks that make the bass amps) and they'd never heard of it. A Google search pulled up almost nothing.

Anybody have any information on this amp? If anyone needs pics, I'll see if I can get one.

Swanson, Mark - 09/09/2008.20:20:41
MIMForum Staff, Michigan

Post a photo or two here, it sounds cool

Schwab, David - 09/09/2008.20:53:16
SGD Lutherie

From what I could find Olson was an a brand of amp made in the 40's

Robinson, David - 09/09/2008.22:15:48
future flatlander

There was a bunch of talk on the Magnatone-Valco forum (yahoo groups) about Stewart Amps. I thought there was mention of the manufacturer, but I didn't find any reference. Does your amp have a transformer-less AC/DC setup? Also what is the mfg'r code on the speaker frame

Stewart, Rick - 09/10/2008.05:15:29

Interesting David S, I'll look into that...

David R- It has a transformer. There are two numbers stamped on the speaker frame. One is: 220250 and the other is: S-551,C7525.

Here's a picture of the front, I'll try to get more pics of the insides later...

Robinson, David - 09/10/2008.07:47:14
future flatlander

One is: 220250

Here is a link for speaker codes

Here is a link for Transformer codes.

Stewart, Rick - 09/11/2008.16:57:19

Stewart, Rick - 09/11/2008.16:57:49

Stewart, Rick - 09/11/2008.16:58:22

The transformer

Stewart, Rick - 09/11/2008.16:58:39

Blurry I know, but it gives the layout of the thing..

Stewart, Rick - 09/11/2008.16:59:03

Stewart, Rick - 09/11/2008.17:09:47

Wow, those pictures probably aren't very helpful... or maybe they are. But they're the best I can get right now as I put it in the shop yesterday to see if they can work some majik on it.

Thanks for the info on the transformers and speakers David. I can't quite make out the transformer number from the picture so I'll have to wait to get the amp back.

Robinson, David - 09/12/2008.08:17:15
future flatlander

The # looks like 831, that would be "Better Coil & Transformer Co." Nice name. Apparently this brand was sometimes used in later 60's Fenders.

Didi you write down the tube line up?

Stewart, Rick - 09/12/2008.09:17:56

I sure didn't. But I do remember there were two 12AX7's made in Holland

Stewart, Rick - 09/27/2008.07:20:04

I finally got the amp back from the shop and it sounds really good. I've attached a schematic for those who wanted to see it..

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