Members Shkmstr Posted December 20, 2019 Members Share Posted December 20, 2019 Just picked up an Excelsior Americana stereophonic high fidelity amp. Really cool guitar/accordion amp and I read a lot of great things. Also got it for a killer deal (at least I think). Here’s a few questions if someone is familiar with the amp, and just general tube amp trouble shooting as well. When I tried it, it wasn’t crazy loud for what I’d expect a tube amp to be. Little buzz but nothing I wouldn’t expect from an older tube amp. I’d say bedroom volume when it’s cranked to 10. This looks to have 2x15s and an 8 inch? I also read these amps have separate speakers for reverb The smaller speaker cable is cut in half. I would assume this is the reverb speaker and it was cut to kill the reverb? Could this cause the lower volume or am I wrong to assume this speaker is for reverb solely? The amp has 3 Amperex 6ca7 made in Holland tubes and an 1 Amperex pre. Are these decent tubes? They look vintage. I have no way of testing them however to know if one or more are toast. The thing needs a serious cleaning and is full of spiderwebs. I have high hopes for it and want to try and do what I can at home without sinking too much cash into it. I’ll add some photos. It’s still in my car so once I clean it up I’ll take some better photos. Thanks so much guys any info and advice is greatly appreciated. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted December 20, 2019 Share Posted December 20, 2019 Looks like a nice score! I've never run across one of those, so I really can't tell you anything more about them than you already know. The cut cable to the smaller speaker does concern me - I don't know if it was intended as a separate reverb speaker or if it was intended to help with high frequencies, but if it was the later, the lack of it being connected can / will change the speaker impedance load, which could affect (among other things) the overall output volume. Have you tried to search online for a schematic for that specific amp? That would be the very first thing I'd want to try to get my hands on before attempting to do any restoration work... Link to comment Share on other sites More sharing options...
Members Shkmstr Posted December 20, 2019 Author Members Share Posted December 20, 2019 1 minute ago, Phil O'Keefe said: Looks like a nice score! I've never run across one of those, so I really can't tell you anything more about them than you already know. The cut cable to the smaller speaker does concern me - I don't know if it was intended as a separate reverb speaker or if it was intended to help with high frequencies, but if it was the later, the lack of it being connected can / will change the speaker impedance load, which could affect (among other things) the overall output volume. Have you tried to search online for a schematic for that specific amp? That would be the very first thing I'd want to try to get my hands on before attempting to do any restoration work... I tried to find schematic online but really couldn’t. I found one for a similar amp, but this seems to be the less common arrangement for these amps. So I haven’t been able to locate it. Link to comment Share on other sites More sharing options...
Members Mikeo Posted December 20, 2019 Members Share Posted December 20, 2019 That was easy https://www.vintageguitar.com/17184/excelsior-americana/ Link to comment Share on other sites More sharing options...
Members Shkmstr Posted December 20, 2019 Author Members Share Posted December 20, 2019 22 minutes ago, Mikeo said: That was easy https://www.vintageguitar.com/17184/excelsior-americana/ Awesome. Thank you. I realize now the reverb chamber has been removed. Now I have to find a suitable replacement Link to comment Share on other sites More sharing options...
Moderators daddymack Posted December 21, 2019 Moderators Share Posted December 21, 2019 The amp looks pretty cool, and at 30W [with power 6L6 tubes] it should be pretty loud. At 50W using EL34 [6CA7] power tubes, it should rattle the neighbors windows. Since you don't have access to a tube tester, I would replace all the tubes, including the preamp tubes [just on general principal], and have it rebiased. Did you buy that from GC in Hollywood? That cut speaker wire is definitely strange. I would suggest you pull and test the speakers. The disconnected one may have had some kind of issue, and rather than replace it, the owner just cut it...dumb move, because as Phil noted, that could totally throw the impedance load out of whack. It sounds to me like you have an impedance issue, and may have a damaged Output Transformer. I would do a very careful discharge of the power caps, vacuum out all the cobwebs and dust/junk/gunk, and then inspect all the caps for leakage, and resistors for burns. On the plus side, it looks all hand wired...but from what I saw in the pics, it was not a particularly neat wiring job...and whoever re-wired the speakers just didn't care....😥 The fact that one of the original Excelsior speakers is still in there and presumed to be functional is fascinating...but it will likely need a re-cone, if it has not been re-coned already. Finding a reverb tank should not be hard. MOD makes all kinds of tanks, and you should be able to find an Accutronics version as well...StewMac has a good selection and could probably match you up. Link to comment Share on other sites More sharing options...
Members Shkmstr Posted December 21, 2019 Author Members Share Posted December 21, 2019 43 minutes ago, daddymack said: The amp looks pretty cool, and at 30W [with power 6L6 tubes] it should be pretty loud. At 50W using EL34 [6CA7] power tubes, it should rattle the neighbors windows. Since you don't have access to a tube tester, I would replace all the tubes, including the preamp tubes [just on general principal], and have it rebiased. Did you buy that from GC in Hollywood? That cut speaker wire is definitely strange. I would suggest you pull and test the speakers. The disconnected one may have had some kind of issue, and rather than replace it, the owner just cut it...dumb move, because as Phil noted, that could totally throw the impedance load out of whack. It sounds to me like you have an impedance issue, and may have a damaged Output Transformer. I would do a very careful discharge of the power caps, vacuum out all the cobwebs and dust/junk/gunk, and then inspect all the caps for leakage, and resistors for burns. On the plus side, it looks all hand wired...but from what I saw in the pics, it was not a particularly neat wiring job...and whoever re-wired the speakers just didn't care....😥 The fact that one of the original Excelsior speakers is still in there and presumed to be functional is fascinating...but it will likely need a re-cone, if it has not been re-coned already. Finding a reverb tank should not be hard. MOD makes all kinds of tanks, and you should be able to find an Accutronics version as well...StewMac has a good selection and could probably match you up. Thank you for all the info! Strangely enough, the only gold top and same configuration one of these I’ve seen is at GC Hollywood, which I live about 5 miles from. But they’re asking $1300 and that one looks to be near mint. This one I drove about 140 miles round trip into the desert to grab for $250. The speakers both look to be original, one had just lost its label. In going to bring it to a local amp tech and see why he says. I just don’t want to sink too much coins into it. I’d like to do what I can here at home, but I understand it isn’t all that easy. Link to comment Share on other sites More sharing options...
Moderators daddymack Posted December 21, 2019 Moderators Share Posted December 21, 2019 yes, but knowing the one at GC is selling [or they valued it at] $1300 leaves you a lot of leeway if you paid $250...If it were me, I would go to the Hollywood GC and ask to see that amp, play it, take some pics of the guts and walk away knowing what a working unit looks like and sounds like Is there any labeling in the back of the mp indicating year of manufacture or where it was built? Link to comment Share on other sites More sharing options...
Members WRGKMC Posted December 23, 2019 Members Share Posted December 23, 2019 Excelsior didn't actually manufacture amps, they had multiple amp manufactures like Valco and Sano build and badge them with the Excelsior name. This one is mainly an Accordion amp made by Sano in New Jersey in the late 60's. Electric accordions typically had a Treble and Bass output and this amp was able to amplify each output separately. Hw well does it work with guitar? You'll have to tell us on that. Given the fact the amp was designed to produce high fidelity using a tweeter its built to be more like a Hi Fi then a midrange amp for electric guitar. Might sound really good on an acoustic guitar or even for a keyboard or Harmonica. Personally I'd be a bit worried pushing those speakers too hard. If you want to use it as is I'd use pedals for drive vs trying to push the tubes into saturation. Those speaker probably cant take a big beating and a passive crossover for the tweeter is not ideal for guitar. I'd simply try it and see what you get and modify as needed starting with a great pair of speakers. Link to comment Share on other sites More sharing options...
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