Brimistor C26 3000/30 ohm

[Mick Seymour]

Hi

My Dad is refurbishing his home made 10 year old GEC 88-50 KT88 amps and the original circuit shows one of these between the U52 rectifier and smoothing caps to protect against excessive voltage during warm up. He never found any when he built them so put 1000V caps in instead (the voltage rises to 625 until the rest of the amp starts drawing current).

He'd like to use lower voltage caps if he can find the device. Does anyone know what the modern thermistor equivalent would be?

Mick

 

[Mick Seymour]

Ok then - new question but probably as daft as the first.

On further investigation it seems the rectifier valve is directly heated so starts wacking out volts as soon as it's turned on. The other valves are indirectly heated so don't draw anything much until they've warmed a bit. It would seem that a thermistor is not exactly what's needed as temperature in the circuit doesn't rise enough for one to change value.

Can anyone tell me what a 'brimistor' was back in the 50s. It sounds like a Les W soft start type of thing.

Mick