Fender champ distortion issue.

[sonate]

I have a mid seventies champ...It's not very clean sounding and kind of distorts.

I would like to give it a service..What should i look for..?

[LJ King]

New tubes,
New electrolytics (caps),
New speaker.

[sonate]

New tubes,
New electrolytics (caps),
New speaker.

Does replacing the speaker make a difference to it's original sound...?

Which are the best brand of tubes..?

[n9voc]

Although not a solid state amp, the Champ is a CLASSIC!

First and foremost - "RECAP" the unit -- make note of the value and voltage rating of all the capacitors, go to a house like "Mouser" for example, and buy new ones (they will be physically smaller than what is in there, but will be fine).  You may not be able to find the exact capacitance rating, I personally would get as close as possible, erring on the high side of the rated capacitance value.  If you can't find the voltage rating on the old caps, go to the next HIGHER voltage rating cap, unless you want a bunch of explosions when you turn the amp on  :tu:   

1) Speaker choice can make a HUGE difference in the sound, from the original to a custom sound you like.  If you want the original sound, get an updated version of the original speaker, other than that - just match the impedance, and make certain the speaker can handle 10 watts (The standard champ puts out 5 watts max, a 10 watt speaker will NOT blow out!)

2) Best brand of tubes -- that's a toughie!  For example, I know folks that swear by Tung Sol, and others that swear AT Tung Sol.  I also know folks that LOVE Sovtek, and others who wouldn't use Sovtek on a bet!  I personally would recommend Tung-Sol for new, RCA or Sylvania NOS for your unit.  Tube choice is like any other "taste" issue.

Well, ya gots my opinion! (That and a few bucks will get you coffee at Starbucks!)

FYI - if you see the capacitor says (.02 MF), that means 0.02 microfarad - old nomencature.

[sonate]

Cheers for the info....

I got this from a junk shop for 30e and didn't know it was a classic amp.

I normally repairs synths so the recap will not be a problem and i will check everything out and give it a good clean up.

I like to get as much info as possible before i get into this, Maybe this is a dumb question but how can i test this speaker..?

Again thanks for all the advice...

Sam.

[n9voc]

 :tu: Short and sweet speaker test:

1) remove speaker from circuit (desolder one side, unplug from cabinet .. whatever, just so you can "get" to both terminals electrically without having it interface with other portions of the amp)

2) Get a DMM, put it onto ohms scale of 100 ohms or less.

3) Drop leads across speaker terminals, listen for slight "pop" as you connect and disconnect dmm onto terminals - and note what ohms reading it is.

The "pop" tells you that the speaker is functional, the ohms reading gives you an idea of the speaker impedance (approx 4 ohms, 6 ohms, 8 ohms, 16 ohms ... etc).

Physically examine the speaker cone, if necessary, repair any small tears (small drop of glue with tissue seems to work well for me).  (or use the info gained above to replace with a new one).

Ive attached a zip file with the schematic and layout of the 5F and AA764 versions of the Champ.  You can find all of the Schematics and layouts for the many generations of Fender Champ from various websites. :tu:

[sonate]

:tu: Short and sweet speaker test:

1) remove speaker from circuit (desolder one side, unplug from cabinet .. whatever, just so you can "get" to both terminals electrically without having it interface with other portions of the amp)

2) Get a DMM, put it onto ohms scale of 100 ohms or less.

3) Drop leads across speaker terminals, listen for slight "pop" as you connect and disconnect dmm onto terminals - and note what ohms reading it is.

The "pop" tells you that the speaker is functional, the ohms reading gives you an idea of the speaker impedance (approx 4 ohms, 6 ohms, 8 ohms, 16 ohms ... etc).

Physically examine the speaker cone, if necessary, repair any small tears (small drop of glue with tissue seems to work well for me).  (or use the info gained above to replace with a new one).

Ive attached a zip file with the schematic and layout of the 5F and AA764 versions of the Champ.  You can find all of the Schematics and layouts for the many generations of Fender Champ from various websites. :tu:

Cheers that's a real help....

[Kludgemaster]

A lot of people like these amps because they distort easily at low volumes. Great for getting big amp sound on recordings.

[sonate]

For a matter of debate...I have been looking at these 'Torres kits' ...Would this be better than buying my caps ect from my local electronics store.

[n9voc]

For a matter of debate...I have been looking at these 'Torres kits' ...Would this be better than buying my caps ect from my local electronics store.

Looks to me like Torres Engineering has done the research, shopping and ordering for you.  It may cost more overall $$ than getting the parts individually from a shop, however, these look like exceptional quality parts as well as known to the the right parts.  I'd have no problem using one of their kits to refurb an amp - if the $$ were in my budget! :tu: