Tube Preamps Should Have This Feature

Freya+ gives you the tube/no tube (buffer or no buffer w/o tubes). Pro-Ject Pre Box RS2 Digital also has a selectable tube preamp output (along with 2 DACs and a headphone amp)

rcm1203

Most short delays at startup are built-in safety checks, my McIntosh SS Amp, mc2250 had a test sequence; My Cayin Tube Integrated AT88is like yours, nothing possible for 30 second check; and my Little Luxman Tube Integrated has a 30 sec test.

Do they advise waiting 10, 20, 30 minutes for warmup in their manual: NO. 

Do we go with the well touted warmup concept, YES

Use your ears, it would be nuts to deny yourself some casual short time listening to some enjoyable content for lack of warmup.

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My friend had car trouble, he will come next week.

My Conrad Johnson Premier 14 preamp came with exactly that sort of stand-by - the tubes are not active until you unmute it.

Having a hard time seeing the use case here. Tubes are designed to get up to optimal temperature very quickly - that’s what the "heater" is for. Transistors can be a very different (and frustrating) story on this front, plus they overheat easily and behave VERY poorly in those conditions. A couple minutes in, and your tubes are good to go.

If you’re entering a several-hours stretch where you want to do several short sessions, just leave it on for that stretch. Or turn it on/off a few times. The tubes will be fine.

If you tally a lot of hours a year and don’t want to pile that onto rare NOS tubes, then the Russian tubes these days are quite excellent.

The Rogue Apollos had a "standby" switch which cut down the high voltage rails while leaving heaters on, but that was specifically for the power tubes (not pre tubes) and even then I hardly ever felt a need to use it.

I start listening right away, and the amp and linestage sound very good within a few minutes; I don't fret over whether the sound is at any sort of absolute peak.  But, I do know someone who complained about the sound of his amps and how long they took to warm up.  The dealer/builder of these custom amps could not figure out why they were failing to please the customer until he heard the amps in the customer's home, under the owner's listening conditions.  It turned out that the owner only listened for short periods and would turn the amps on and immediately start to listen, while the dealer/builder kept the amps on all day.  The issue wasn't tube warmup, it was the capacitors used in the amps.  The amps had Blackgate capacitors, and when they were swapped out for other capacitors, the warm up became MUCH shorter.  It turned out that Blackgates take a very long time to warm up and stabilize.

I have the same sort of issue with my music server which is a solid state unit.  The manufacturer recommends leaving it on all of the time and claims it does not sound its best until about 24 hours after being turned off for a few hours.  This has to do with the capacitors in the power supply of the unit.