Gibson Invader Tremolo Woes

[Pickupmaker]

Does anyone know where I can obtain the optocoupler LDR needed for a 1964Gibson amp? Apparently the present day Fender replacement component uses a LED in conjunction with their LDR and it's triggering value is all wrong for Gibson amps. The Gibson optocoupler uses an incandescent lamp to trigger the tremolo tube. I tried the Fender type and it pulled the amp's volume down to about half power with the LED constantly on full bright. So I substituted the LED for the light bulb and it appeared to work fine for about 2 weeks of testing the tremolo a minute each day, then the problem started again with the amp's channel 2 volume decreasing each day with or without the tremolo on. I have since installed a small toggle switch to disconnect the LDR from the circuit and the volume and power is restored. Maybe the light bulb is too strong for the photo resistor and is breaking down it's value. Apparently this amp's circuit design will only tolerate the OEM part. Any help would be greatly appreciated. Nobody carries Gibson amp parts.

[Enzo]

What is wrong with people, they don't stock parts for 42 year old stuff?

Most Fender optos I know use a neon bulb, not an LED. No reason an LED couldn't be used in an opto, that is what is inside of a VActrol and other similar. But in this tube circuit, the LED current might be on the high side at maybe 10ma.

In your experiment, did you install an actual LED or did you put in a neon and you are calling that an LED?

I don't care how bright it is, yout bulb didn't wear out the photoresistor.

I haven't found a substitute I like for the bulb in the Gibson opto, if that makes you feel any better.

Is your amp the GA30RVT maybe?

The photocell is a resistor with high resistance when dark and when light shines on it the resistance goes down. Since it is wired to ground from the signal path, any light shining on it will drop the signal level.

The trem tube drives the light bulb. the cathode resistor is adjusted to provide a current through the lamp that doesn't quite light it, then any trem signal through it makes the light flash on and off and so tremming the signal.