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View Full Version : Just picked up a $200 Champ, have a few questions ?

Totally Bored
03-03-2009, 05:35 PM
Just picked this cute little baby up for $200. These Forums give me amp gas and I think I'm a littlle out of control. At least I'm into cheap stuff ?
It works and sounds decent. Somebody stuck a 6L6 Power tube in there so I removed that and plopped in a RCA 6v6 greyplate that I had laying around. Amp also has a RCA rectifier in there. I'm assuming that it's a 5y3 ? There are no markings on it so ?

http://home.roadrunner.com/~theoutpatients/P3030100.JPG

So I have a few questions for you guys.


What year is it ?

Chassis is stamped: A45258

Choke ( I think its a choke) is stamped : 022905 and 606-3-34

Power Transformer is stamped : L010020 and 05A 837 and 606-4-13

Chassis shot

http://home.roadrunner.com/~theoutpatients/P3030086.JPG


Looks like someone had worked on the amp at one time by the 2 Power resistors and 1 cap that appear to have been changed. I'm trying to figure out if these values are what I want in there or should I put the stock values back in. Maybe someone did a worth while thing or maybe not ?

http://home.roadrunner.com/~theoutpatients/P3030084.JPG

Also, theres a little cap on the the Power Tube, whats up with that ? Don't see that on the schematic.


http://home.roadrunner.com/~theoutpatients/P3030094.JPG
slartibartfast
03-03-2009, 06:06 PM
http://www.ampwares.com/amp.asp?id=42

Cool amp, Ive got an 82. Great amp. Changed the speaker to a blue pup ceramic. Big improvement. Great amp for trying different tubes. Might just spoil any other amps you have for you
Brett
Totally Bored
03-03-2009, 06:16 PM
Thanks

So after a little bit of Google-ing I think this amp is a 1974.




Anybody have any thoughts on those Power resistors and the 1 changed cap and the one cap the Power tube ?
phsyconoodler
03-03-2009, 06:52 PM
The resistors are an attempt to bring the raging 6v6 bias under control.The cap on the power tube is in the layout diagram at www.schematicheaven.com under Champ.
smolder
03-03-2009, 06:57 PM
Cool score... I have a '74 also. I love playing through it... even better with a nice alnico 12" speaker.

Not a tech, but I did sleep in a holiday inn last night.... ok actually I did a boat load of reading when I got mine. Replace the speaker jack with a 1/4 inch and do the same with the speaker wire, then you can use a separate cabinet when you have the chance.

I would suggest clipping the cap that goes across the bottom of the power tube. You can also lift the ground on the bass pot to get more gainy sort of grind (or put a switch or pot between).
mbratch
03-03-2009, 06:58 PM
The cap on the power tube is supposed to suppress oscillations I think. Fender added it in the early 1970's. Evidently, a bunch of their BF champs must have been oscillating?? Just kidding. My experience is that it suppresses some of the nice chime/sparkle of the amp.

If you want to have some fun with it, connect the output to a 12-inch speaker or 4-ohm cabinet. It's awesome to behold. :)
71Model
03-04-2009, 07:10 AM
The cap on the power tube is supposed to suppress oscillations I think. Fender added it in the early 1970's. Evidently, a bunch of their BF champs must have been oscillating?? Just kidding. My experience is that it suppresses some of the nice chime/sparkle of the amp.

If you want to have some fun with it, connect the output to a 12-inch speaker or 4-ohm cabinet. It's awesome to behold. :)

Oh yeh, I got a Vibro Champ and when using a 1-12 closed cab it Rocks! Big Sound! :RoCkIn

I heard that the Vibro Champs "breakup, overdrive" a lil better(opinions) because the Vibro tube is in the circuit????

Champs are awesome, sorry I don't know about the Resistors, you might want to send it Ben Fargen, he knows em pretty well and he's trustworthy.
Totally Bored
03-04-2009, 07:32 AM
I would suggest clipping the cap that goes across the bottom of the power tube. You can also lift the ground on the bass pot to get more gainy sort of grind (or put a switch or pot between).

I think I'm gonna clip that cap. I remember that my 72 DR had that on the Power Tubes and I removed them. Didn't know about the ground on the bass pot thingy. I'll have to try that, thanks.
teleamp
03-04-2009, 07:39 AM
The cap on the power tube is supposed to suppress oscillations I think. Fender added it in the early 1970's.....

Exactly, they were having lead dress issues and bandaided the oscillations with the "snubber cap".