'65 Vibro Champ - lack of treble?

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JSett
PAT. # 2.972.923
PAT. # 2.972.923
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Location: Old Hampshire, Old England

Re: '65 Vibro Champ - lack of treble?

Post by JSett » Tue Sep 14, 2021 7:39 am

sookwinder wrote:
Tue Sep 14, 2021 7:21 am
I have spent a lot of time working with the VC amp circuit, back in the day electrolytic capacitors were very expensive hence Leo chose the smallest available cap, so those very early VC have far less filtering than later model. For me what ever the year SF or BF I always replace the cap can with a 40/20/20 version (whether that is a 40/20/20 or a 20/20/20/20 and two of them in parallel to create the 40 it doesn’t matter)

There are a shit load of genuine VC schematics out there , even within various up grades to the VC, I like the last BF version through to the early SF version but with the proviso to have the 40/20/20cap can

As far as the 8ohm speaker yes it will make it sound a little darker then the correct 4ohm one
But it won’t kill the tranny
Have you got two 8 ohm 8” speakers?
Connect in parallel and see how it sounds

Also stick a shorted RCA plug into the vibro female RCA foot switch connector and turn the vibro pots down to zero and that will give you more (non vibro) gain

I have had a treble tone cap die on me in one of my VCs, things don’t last for ever

Later SF versions had an extremely small cap across to if the 6V6 pins to stop oscillation
Yours would not have that and should not need it
Yeah, I definitely preferred the 40/20/20 over the 20/20/20 - the noise floor was greatly reduced. I definitely don't have two 8" speakers anywhere, but I have loads of 10" dotted around the house/garage/attic. I could probably put something together and have a play when I have the time.

I dropped in a 1/4" socket in place of the RCA tremolo connection and need to throw together a little switch for it. Didn't know actually turning it off would make much difference but it makes sense

I'll have it back open in a day or two so I'll check that Treble cap, pretty sure it's 250pF on the schematic and an easy one to swap.

Thanks for the tips
Silly Rabbit, don't you know scooped mids are for kids?

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