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Fender Champ Mods


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6/24/1997 2:00 PM
Jim Gross
Fender Champ Mods
Just wanted to see if anybody has come across  
the "killer" mods for a Fender Champ. I have a  
CBS era amp, so no big deal about modifying a  
classic amp to worry about. Just want to have  
a nice sounding little amp with a good tone  
for blues.  
 
Thanks, Jim.
 
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6/24/1997 7:21 PM
anonymous
I put in a Hammond OPT to get an 8 ohm tap and then added a 10" Eminence speaker. I wouldn't call it killer but it did fill out the bass somewhat.
 
6/24/1997 9:08 PM
Paul Markwalter

Strip the circuit board and build a 5F1 Tweed Champ, omiting the treb. and bass controls. Put a 25x25 electrolitic cap across the 1500 z cathode res. If 3-20 @450 can cap is good leave it and replace voltage network res. w/a 10k 1w and a 22k 1/2 w. Leave xfrmers alone. Replace spkr w/Mojo 8" 4z 15w . If you doubt the filter can, replace w/3-16x475 Sprague electrolitics. You might have room on the board for them. Stick with the 5Y3, 6V6, and 12ax7. Look at both schematics and you will see you only need 15-18 parts @ a cost of about $75. including spkr. Save all parts if you want to return it to stock later when you sell it.... but you won't. You will then have created killer. If you need schems.,layouts and parts, I can help. Have fun, Paul
 
7/13/1997 11:39 AM
M.Romasco

Paul,  
Ive got a few questions for you about the champ mod. First, why do you add a bypass cap to the 15K ohm cathode resistor - it's not in the 5F1 scematic that I have. Second, do I really need to get a new speaker? Whats wrong w/ the orig. Third, I have a Vibro-champ that I want to do this mod to. Would it be safe to leave the trem circuit or would I have to bias the amp differently? What is the approx. voltage of each plate that I am looking for? And finally, what kind of tonal differences will I get with different value filter caps?  
Matt out.
 
7/23/1997 7:53 PM
Paul Markwalter

Matt, The 25x25 cap ads gain and fat but the res.  
is 1.5k, not 15k. Put the cap on a SPST switch. Wire the switch to ground, - side of cap to other side of switch. Have it both ways. I sugested a new spkr. for better power handling cus then you can hear the 6V6 sing without spkr. dist. getting in the way. Look for, 6V6 plate 350-380vdc, 12AX7 plates 150-200vdc. Going with 5F1 filt. and votage devider network will get the amp closer to 5F1 tone. By, Paul
 
7/24/1997 5:46 AM
M.Romasco
Thanks Paul,  
Have you tried any of the Kendrick 3.2ohm replacement speakers for Champs? What is a good speaker to use to hear the 6v6 "sing" w/o speaker dist.?  
Matt.
 
7/25/1997 4:29 PM
anonymous
Allow me to put my 2 cents worth in.. I modded my Vibro Champ two days ago using the mods in the new Gerald Weber book. Sounds great! I also had the Kendrick speaker and was only mildly impressed. I ended up using a Weber alnico speaker that sounds fantastic. Both have websites to peruse. Good luck! Mike
 

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