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Vibro Champ - 8" or 10"


Any Vibro Champ experts out there? I need advice.
Just bought a mid 70's silverface VC. Anything I should examine immediately after it arrives? Should I change out tubes? Have it looked at be a tech?

Biggest question: Keep the original 8" speaker? Replace with a Weber or something? Replace the baffle and put a 10" in there?


Big Tim

If the tubes are in good shape keep them in there. Getting it looked at by a tech for caps etc. isn't a bad idea- you'll know where you stand with getting them replaced or not.

I've always wondered about the change from 8" to 10" too. Is there a whole lot of volume gained by one of those Weber speakers?


Silver Supporting Member
As a long-time silverface Champ owner and lover I'd suggest the following:

1) Make sure you are running a vintage 5Y3 and not one of the new production units that result in higher plate voltages. The silverface Champs run the 6V6 well above its rated spec to begin with and running a Sovtek rectifier could toast an old 6V6 tube and take the cathode bypass cap with them. Voice of experience here. RCA 5Y3GT rectifiers are easily found at very reasonable prices.

2) Even with a proper 5Y3, you may wish to raise the value of the cathode resistor from 470 Ohms to 800+ Ohms. This will run the 6V6 a bit cooler and increase its life. If you do this, however, be sure to replace the bypass cap at the same time and increase its rating to 50 Volts or more.

3) Regarding speakers, ignore the inbuilt 8" and run it through a pair if 12-inchers wired to give the 4 Ohm impedance that a Champ wants to see. I made an RCA to 1/4" patch cable and a parallel box to make it easy to connect other speakers to my Champ (picture below). It's amazing how great these little guys sound through some real speakers.

Have fun!




Silver Supporting Member
it will be an 8 inch speaker. The baffle will be glued it and without do major structural change, very difficult to replace. Will totally ruin resale value. Be better off getting another cab made.

Things to look for: 3 prong cord is a must, can save your life. Chances are, if somebody has gone through the trouble of putting in the cord, that the electrolytics have been replaced as well. An amp tech can check this out.

I wouldn't replace the tubes right off unless they are actually bad.

I don't know if you necessarily get more volume from a 10" over an 8". You should get better bottom end, if the amp circuit has the capacity to deliver it. Sometimes a little tweaking is necessary to take flab out, that was revealed when a larger speaker was used.


Get a decent 8". Sounds nice like that. I use a Jensen.
Plug into an external cab for extra ooomph..


Senior Member
go for a 12"er

i just got my silver-face vibro-champ set up with a new cab this weekend. it sounds fantastic with a good 12' speaker. its like a baby deluxe reverb and really opens up. it doesn't sound like a toy like it does with an 8"er in it

you'll need a new cab though, sorry. i got a beatiful cab from david allen that worked perfect



Jon C

Silver Supporting Member
I have a Weber Signature 8S in one and it sounds very good... just as one example/idea.

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