rogonzab
374 posts
Aug 30, 2013
8:19 PM
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Hi,
I am the happy owner of a Fender Champ Silverface. I saw the amp for a good price (at least for the chilean amp market) and I jump on it.
The champs looks very clean for his age, an there is no mayor esthetic problems, just a few scratchs.
The amps is not original, it has a diode rectifier instead of the 5y3, and the speaker is a 8ohms VOX branded one.
The amp sounds good, very aggressive sound (but in a good way), so I am happy whit it.
There is something weird.
I can put the volume on 10 an no feedback on the input 2.
I can put the volume on 8 an no feedback on the input 1.
Whit the volume on 10 the sound is distorted, but not really distorted, as you would expect from a tube amp on 10.
It does have a 12ax7, and I would think that a 5w tube amp is louder than this amp. When the volume is on 10 it is loud, but not that loud.
So, there is a question:
How loud, and distorted, would be a champ? I know that it is a clean amp, but I think that there is too clean/quiet.
I will post pictures and a soundclip or a video.
P.S: NAD = New Amp Day
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SuperBee
1395 posts
Aug 30, 2013
11:55 PM
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Good score. :0)
What mic you use?
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Kingley
3079 posts
Aug 31, 2013
1:48 AM
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The first thing that comes to mind is the same as SuperBee. What mic are you using? Is it a high impedance microphone? If not then you'll need to either get a high impedance mic or a low to high impedance converter.
I'm pretty sure the Silverface Champ was 4ohms. So you might have a speaker mismatch. How much that would affect the sound though I can't really say. Any other problems with the amp should be pretty easy and cheap to fix. It's only a basic circuit with a few parts. As long as the transformers are ok, then your costs shouldn't get too high.
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rogonzab
375 posts
Aug 31, 2013
6:32 AM
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SuperBee, yes it was a nice score.
My mic is a Universal 312 Shell, whit a Shure CM 99b86.
The 6v6 seems original, I dont know about the 12ax7. Maybe the tubes are old, or not?
I love the tone of the amp, really in-your-face-sound.
I am going to buy a weber speaker, they are the only ones that sells speaker whit 3.2 ohms. I still dont know if alnico or ceramic, I think that Alnico will be a more "original" upgrade more close to the stock speaker, what do you think?
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SuperBee
1396 posts
Aug 31, 2013
2:01 PM
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Hi Rogonzab, yes that 8 ohm speaker will be sounding quieter than the original. I reckon that is the most likely starting place to look go why it is on the quiet side.
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LSC
494 posts
Aug 31, 2013
2:30 PM
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I'm not sure if this year Champ the original speaker would have necessarily been an alnico. I think by that time ceramic would have been the norm due to cost. In any event, as soon as the original speaker is gone then whatever value being all original may have is lost anyway, and in a SF Champ were not talking a lot of money anyway.
I would suggest simply going for the best tone, which is the point of buying most any amp. With that in mind, I prefer alnico speakers for harp and would recommend a Weber 8A100. You might have to remove the magnet cover to fit it in the cab but that is a matter of one screw. Weber is having a sale at the moment with 10% off but it only runs through August 31.
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LSC
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Greg Heumann
2341 posts
Aug 31, 2013
9:42 PM
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Don't use input 2 - when nothing is plugged into input 1, it grounds the input - so your mic is seeing a heavy impedance load (through 2 input resistors in series to ground.) Still, unless your element is weak, there might be something wrong with the amp. A single 12AX7 pre-amp section is used in lots of amps (including the Kalamazoo, with which I'm very familiar) and has sufficient gain to get to feedback before the volume is up to 8 on most of them. The speaker wouldn't make that much difference unless the amp expects, say, a 2 ohm speaker. There's lots more to an amp's gain than the tube in use. How is it biased? How is the supply voltage? Is the coupling cap still working properly? I would recommend having a good amp tech look it over for you.
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Last Edited by Greg Heumann on Aug 31, 2013 9:45 PM
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rogonzab
376 posts
Sep 01, 2013
3:13 PM
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thxs to all, I will send the amp to a tech, I guess that is alway a good stating point when you buy amps that are old.
This amps are cathode bias right? so I can put an extra 6v6 that is laying arround in my room to test if that is the problem, or do I need to bias first?
I am very exited about this amp, much much better sound than my Laney Cub 10.
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