C.M.I. amplifier...Gibson SG Line ?

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eleemosynary1

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Hi,

Hope this post is OK for this section of the forum. I have a guitar amp I traded a Harmony flat top, (with a broken neck rod), for over 20 years ago. The amp still works absolutely great even today. I can't read the model or serial # on the tag in back so all I know is that it says C.M.I. Electronics, El Monte, CA on the back. (I have read that both Gibson and C.M.I. were both controlled by Norlin back in the mid-70s.)

I always liked it since it reminded me of the old Gibson SG line of amps that was available back in the days I bought my trusty J-40 flat top from a shop in Manhattan, KS. I wasn't truly into "electric" guitars at the time, but I spent several hours fooling around with their in-store electric stuff even though it was out of my budget as a student. I could be mistaken, (and I probably am), but I thought those SG amps were ALL tube types. The amp I have here has 2-12s (Gibson Ultrasonics), and an all solid state amplifier. There is the usual "Phase Shift" as was built into most if not all the SG amps. I don't ever remember any markings or model number on the front of this amp, but it could well be that it was removed before I got ahold of it. (It's been a reliable amp for several years now.)

I would appreciate anyone who might be able to help identify this thing to chime in. I'm trying to narrow it down to a "model" if possible.

Thanks,

Bob
 
CMI Electronics SG Systems Amps

Bob,

I don't know if you're still monitoring this forum or even if you still want any information on the SG Systems amp you described in your posting. I just came across your message on the forum yesterday while trolling for technical and repair information for an SG-410 that I want to sell. If you're still interested, here are a couple of links to some informative sites:

http://www.guitarsite.com/hotlicks/about1657-0-asc-0.html

http://www.harmony-central.com/Guitar/Data/SG_System/

doug.higgins@jeppesen.com
 
Hello geezer,

The first link to the forum you supplied was certainly some interesting reading. Though obviously I am not an avid poster here, I do enjoy checking in occasionally and I certainly appreciate your input. Indeed I did run across the information contained in the second link at some later date (after my initial post).

I suppose it would be proper here to relate some information I eventually DID come across more than a month after I made the initial post. (Thanks to a gentleman with Gibson Customer Service). To verify his suspicion of what I might have, he sent along a digital image of an old advertisement for the amplifier, including the "features and specifications". I was quickly able to verify that the C.M.I amplifier was indeed a Gibson G-105 model. (If only my amp would have still had the big chrome "Gibson" logo on the front grill. LOL) Gibson additionally sent along an electrical schematic in case I ever needed it. (I should have known to give them a call earlier, I suppose, especially since it had those two 12" Gibson Ultras mounted in the case).

For the record, here are the links I sent to Gibson to take a look at:

https://img.photobucket.com/albums/v162/eleemosynary/Various/front1.jpg

A close look at this pic and you may be able to pick out the C.M.I, El Monte, California designation on the back plate:

https://img.photobucket.com/albums/v162/eleemosynary/Various/back1.jpg


Thanks again for responding geezer, and after reading the forum link you supplied on the other CMI guitars and equipment, I see my quest for information was actually an easy one. It has to be a "royal pain in the rear" for those guys to positively identify some of those 60s and 70s guitar imports. Actually, I'm sure I owned a bunch of them myself at one time or another. Hah.

Thanks again,

Bob
 
You should be able to get a "Gibson" logo for the front, I know you can get Fender from other sources, I assume Gibson would be the same.
 
C.M.I. Electronics SG Systems Guitar Amplifier

Bob,

Thanks for the update and the photos. I definitely can see the lineage of the SG Systems version including the control knobs, power polarity toggle switch, even the grille cloth. Clive from down under had a terrific idea about contacting Gibson for a replacement logo. If your amp originally had one, hopefully there are a couple of small holes in the cloth that would indicate the relative position. It seems there is quite a history with these units, and piecing information together has been a challenge (huzzah for the Web!). Tube replacement seems out of the question due to availablity (the two RCA 8417s). My reverb is out and the amp has some distortion. Also, everyone that has posted anything about these units has commented on their weight. Mine has only left the premises twice in 23 years, the last time just recently to get a price quote at a music store. Based on the history I've gleaned from these forums, these amps have a cachet that's mostly nostalgic. So I think perhaps I'll donate it to a local school that's in need. I tried to attach some jpegs but the file size exceeded this forum's limit (but I just purchased a digital camera, so I'll take some more shots to post).

Cheers!

Doug
 
Well Clive, I will keep my eyes open for a proper logo although I have downloaded the (.pdf) logo artwork specs from Gibson and might be tempted to make a reasonable facsimile of it myself, if necessary. Doug, I'm fairly certain that it once had a logo that, if attached, would pretty much make it a "dead ringer" for the amp shown in the old literature piece photo sent to me by the company. (Link follows). It's kind of "washed out", and not at all high rez, but hopefully it's adequate enough to get the point across.

https://img.photobucket.com/albums/v162/eleemosynary/Various/G-105_.jpg

At some point I believe I will also recover the amp with a more original tolex type material as well. Leaving the grill and other hardware intact, of course.

Also, it seems those tubes in your amp really are difficult to replace, although it would be nice to run across an easy fix or replacement. Those particular tubes seem to have some unique characteristics from what I've been able to gather from the few available sources I've seen so far. I would surely have enjoyed playing through that amp when it was in pristine condition, just for the experience. Haha.

It was nice to get some input on this.

Bob
 
CMI Electronics SG-410 Amp

Well, I did it! I got the old girl working again, and she sounds fantastic! I played thru it for several hours last weekend and had a blast! I found RCA 8417 power tubes on eBay as well as a 12AX7A. I also found a great amp tech locally (Noel at StubbyFex) who cleaned all pots, biased everything and replaced a few caps and one tranisistor, all for $50. He's awesome! The rest of the amp is in perfect condition with nary a scratch. Now I'll have to find some excuse to keep it that will convince the wife. Any ideas? I also did quite a bit of research into the origins of Norlin, CMI, Standel, Gibson, Moog, Selmer UK, Olds, Reynolds, Epiphone and other related companies while trying to locate information about this amp. Fascinating!
 
I would have to feel pretty darn good about getting that amp crankin' again for around $50. Sounds like a good deal to me. Unless you were contemplating purchasing some other musical equipment in the near future, maybe you should tell the wife that it was much cheaper to get the old amp fixed up than you ever imagined, so you probably will just hold on to it so you don't get tempted to spend money on something more expensive, (at least for a while). Something about saving money usually works pretty well, don't you think. :)

I dug up a lot of that company info stuff during my amp research as well. It is indeed interesting.

I wish I could play my LP Custom through that "410" for a while just to hear. Congratulations on the fix.

Bob
 
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