My Laney VS30 212 at band practice last week decided to intermittently cut out, but not fully just the volume would drop out then return about 5 mins later. Not sure if this was a common problem. It might be the valves but did not want to go and buy a load more if its a simple solution. Can anyone help please?

Bad connection? Loose fittings? I used to get a crackle from my amp when I turned the volume or balance knobs. A quick spray of WD 40 down the shaft after removing the knobs fixed it.

sounds like a bad tube or your transformers shot

What is the impedance on the devices? It sounds to me like the amp and the pickups are not rated for each other.

It's most likely the battery isn't producing enough voltage, though it may have been adequate for your other guitar.
However, you should discuss the issue asap with your dealer and/or Taylor support.
https://www.taylorguitars.com/support
Support

OFTEN Roland has the opposite sense of normally closed contacts versus normally open. Test the switch with any continuity tester or an ohmmeter to see that the contacts work and come out to the switch. ALSO some amps require a TRS type connection (three wire plug) and others do not. From the schematic it appears that the Laney may REQUIRE a normally closed contact. There is also a pull switch involved that you MAY have to change the state of for operation of the pedal.

Here is the scheamtic for your amp:

http://elektrotanya.com/laney_aor100h_sch.jpg/download.html

Scroll down to the link at the page "Get Manual" and click to download. It is a JPG type file.

Such a long delay and a slow return to volume is puzzling. If the return came back in say 30 seconds, I would suspect 1/2 of the V1 tube (12AX7) might have a failure of the heater. When it has failed see if this tube has TWO points of light in it. The cooling down and warm up would give a 15 second ramp up or down in volume. This tube has a path around it that would sustain a very low volume. Try swapping one of the other 12AX7's into this spot. If the sound totally goes away replace the one that was in V1 at first place and see if problem goes away.

Start by monitoring the power supply voltages when it fails. At what point does it return? Is it intermittent or do you have to do something specific to start it working again.?

clean all "vr" (variable resistors) like volume bass treb etc, sounds like bad contacts. this happens due time while they oxidating. maybe helps. use "contact" spray for best result

This is a tiny amp good for practice at low volume levels. You are likely overdriving it and the power amp chip goes into thermal protect. If you volume level is much louder than a small boom box, you are driving it too hard. Best to get a bigger amp.

CHANGE THE TUBES. ARITHEBASSPLAYER