Neon Bulb Replacements for Fender Optocoupler

[Lee_ranaldo]

I don't live in the USA or got a chance to buy stuff from the internet..
i need a replacement for the neon bulb in a silverface era fender tube amp.

Which are the correct ratings for a replacement, to avoid a huge "tube amp failre during a gig" , by using an incorrect neon bulb

thanks!

[Paul Perry (Frostwave)]

Provided you have the series resistor in place, I can't imagine a catastrophic failure of a substituted neon. The main prob would be, maybe not enough light, like when you replace a LED in a LED/LDR situation.
It used to be, the only neon I ever saw (the little thing with the flying leads) was a NE-2. I don't know it that was the one used in that amp though.. any photo around?

[Lee_ranaldo]

according to an internet site..
the model is NE-2 neon bulb lamp
as used by many LA-2A compressors.. (also all tube)

the max ratings for that model is 200VAC at 0.01 Amps..

i was thinking of using x-mas light bulb from china that are so slim as the original one, and are rated to be uses in series directly to 220VAC.

The problem is that the inside elements (cathodes?) from the original lamp looks bigger , and i'm afraid off messing this tube amp desing.. (new tubes everywhere..).

There are other choices for pilot lamps that are rated to 220VAC at any current that are used as pilot lights for light switches in appartments or similars.

any suggestion=
Thanks Paul!

[Paul Perry (Frostwave)]

I'm not so sure about those Xmas tree lights, there are quite a few different arrangements of those.
One thing I would try, is the neon 'ready' indicator light on camera flash units (I think even some disposable cameras might have had these). You have a neon bulb, connected by a high vlue resistor to the main flash capacitor, when the cap is charged up, the neon breakdown voltage is reached & it glows red.
Neons are like LEDs, in that when the current flows, it will burn out, unless it is limited by a series resistor. Any neon indicators designed to be put straight across the mains, have a hidden resistor in the fitting somewhere!

[smallbearelec]

If you want the OEM replacement photocoupler assembly, it's about a $10.00 item from Sovtek. I can get it for you the next time I place an order there. You would just have to find someone in Chile who has a PayPal account to send funds for you, or send some cash in an envelope. You can contact me at smallbearelec@ix.netcom.com

Steve Daniels

[Lee_ranaldo]

thanks Steven an Paul for both replies!

yes i know some neon bulbs has a small resistor in series inside..
i'm gonna find those ready neon bulbs to test.. if i got a chance to find a friend with a paypal account , i'll follow your suggestion steve. since i need desperately some CA3080's for a broken tonepad smallstone that i have lying around. (and some other ic's)

there is an article on geofes how to turn a tube based tremolo with mosfets and getting the same results.. (but that wouldn't be original...)

thanks!