Channel switching in tube amp with solidstate relays

[Jazz P Bass]

True enough.
Keep us posted.

[hewo]

vc3112 vtl5c3 degradation from signal abuse

I would much rather have a 1.5 ohm resistor in the signal path than a 50 ohm mosfet.

But that's just me.

Does the element type & resistance have an effect on the signal?
I would imagine that it depends on the application.

Edit: taking note of the mosfet datasheet, there is a flat .12 db insertion loss.
No such data is available for the Vactrol.

I bought a bunch during the 90's discovering degradation of slm's installed ones. Then I discovered wide variance resistivities between the replacements (RP country manufacture) benchtesting using one penlight battery to energize the internal diode (IR?). Literature specs profess kilo ohm'age however I measured fractional of one kilo and that's only with 1.5v battery.
After guitar signal abuse, resistivity worsens and imparts this on signal passage. You must benchtest the suspect abused LDR out of circuit. Spec says dissipation capacity tenth watt, quite unbelieveable owing to schematic call for quarter watt unles otherwise posted.
Gotta upgrade into lower actuation energy physical relays, saw low voltage ones onboard japan eight bit modems ancient computer cards. Don't know whether an easier solve using a higher grade vactrol if any exists.

[Jazz P Bass]

Well, maybe the '90's units where inferior to todays manufacturing methods.
Don't know.
Laying down the resistive element is probably a more efficient process now.

The vtl5c3c specifically calls for 40ma's current across the led to achieve the 1.5 ohm on resistance.

Anything lower & the value is up for grabs.
http://www.excelitas.com/downloads/dts_vtl5c3c4.pdf

[g1]

Well, if they're good enough for boogie, there's a 10 ft. pole for that .
But as Jazz mentions, maybe they are better now.
FWIW, Fender started using them a fair bit in the red knob era, then dropped them.
One of the designers from then said that some of the "custom" resistors of those Fender amps were for altering the gain of the circuits due to the wide variations in the opto's.