Inrush current limiters, my thoughts and yours.

[kward]

May add more solid-state complications to the tube circuit.

More things to fail?

Definitely more things to fail. And for that reason I'd be cautious about using it when a thermistor will do the job just as well.

But since we're discussing that particular timer, a simple improvement to that circuit, IMO, would be to use an electronic switch (a Mosfet or BJT) with an R/C controlled gate or base voltage that ramps up over some time interval, and when that voltage is at the relay's threshold value, the relay kicks in and closes the circuit to short out the 10 ohm current limiting resistors. It may be even simpler than that by replacing the relay itself with a transistor. I'd be surprised if such a device does not already exist for controlling a 120V mains line, and I would expect they shouldn't be that expensive. Anyway, just thinking out loud. I've never had a deep need for a time delay circuit in a tube amp.

 

[WopOnTour]

May add more solid-state complications to the tube circuit.

More things to fail?

There's not much for solid-state in this Antek soft-start device aside from a rectifier for it's own power supply and a zener that will delay the start-up based on some resistor values.
I've been searching for an alternative to the Sophia delay relays for sometime as one has failed on my Fisher Model 200s and they are now unobtainium
WOT

 

[Mr Boochie]

There's not much for solid-state in this device aside from a rectifier for it's own power supply and a zener that will delay the start-up based on some resistor values.
WOT

I hope that relay is a quality part.

 

[gadget73]

Resistors for inrush, bypass with a relay. SImple enough. Could modify it and sub the two resistors with one of those NTC thermistors. That would give more initial resistance that slowly reduces until the relay closes. Less voltage difference for the relay to handle so it should arc less, but more initial resistance so it makes life on the power switch easier.