Dating fender champ
This rare Champ is the similar to the 5F1 Tweed Champ but has a choke in the power section rather than the Pi filter that the 5F1 has.The screen and plate voltage come off the same filter cap which is a design flaw.Lots of different speakers were used in the blackface and silverface era Fender amps.In a BF Vibrolux Reverbs you could have either Jensen, CTS or Oxford, the BF Super Reverbs had Jensen, CTS, Oxford or sometimes JBL, the BF Pro Reverb had Jensen, Oxford or Utah, .
There have been a number different models over the years and some are more desirable than others.
There are also exceptions to the rules where Fender delivered non-standard speakers in special orders, Christmas campaigns etc. See our Buyer’s guide to vintage Fender amps for a guide and picture gallery of the known original speakers in the blackface and silverface amps.
You may compare these with your own speakers to determine what you have.
These amps can be made to sound more like a 5F1 by disabling the tone controls and changing the filtering circuit. If you play you Champ regularly replace it every 6 months or so. All amps need their electrolytic caps changed out every 7-10 years.
Some Silverface versions has a snubber cap placed on the power tube. If yours still has the original caps it's not performing it's best.
All of these Champs used a 6SJ7 pre amp tube rather than the 12AX7. These amp have a nice grind to them but have very little volume.