Gem Model P vibrato

[huibn]

I have this beautiful Gem Model P, but the vibrato is way too slow. There is a knob for adjusting it, but i can adjust it from extremely slow to slow.

There should be a potential meter on the lowerc/bass card, but i cant find it. i suspect the white wire on that board(as you can see on the picture, on the upperside of the first soundboard) leads to the vibrato knob.

Can anyone tell me how i can adjust the speed (or depth) of the vivrato?



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[joelindsey]

As far as I know the Gem Model P has the same electronics as a Vox Jaguar. Try replacing all the electrolytic capacitors (the 3 green and 1 blue parts towards the top) on the left most board, as they very likely could have gone bad over the past 40-something years. The green ones are 5uF, correct?

Another thing you could try is lowering the value of the potentiometer that controls the vibrato speed. I think it controls how quickly those caps charge/discharge (thus the rate of vibrato oscillation). If it's a 5k pot like the Jaguar, try a 1k and see how that sounds. If that's too fast, a resistor across the 5K will drop the value down a bit.

[joelindsey]

Almost forgot,

Try reducing the value of those green caps to something lower. If they are 5uF, try 2.2uF. That should increase the rate because the smaller caps take less time to charge/discharge.

[julienpz]

Hi,

I also have a problem with the vibrato of my Gem Model P Deluxe which doesn't work at all. I changed some caps but did not fix it. huibn , could you send me a detailed pictured from your vibrato board. That could be very helpfull for me.

thank you