How Long "Burn-In" Time for Valve Mics?

[Umlaaat]

Just got a 2247LE.. Whats the burn in time for a tube mic?
Do you leave it on all the time or fire it up an hour before session?

[lord_bunny]

I just got the Peluso P12 last month and have been wondering the same thing. Lately I've been letting the the pre and mic warm up for a few hours... but then again I have no idea if this is at all benifical.

[The Byre]

Unless something is very wrong with the mic, almost no time at all. A few mins. at the most.

[roger]

apparently they do sound different after a few hours......i can't hear it though.

done plenty of tracks where left for a few hours and returned to finish a bridge/chorus double etc and there is no perceivable difference between the 'cold' and 'hot' tracks..........but i have been TOLD it's always better to get em cookin before you start trackin....??!! quite possibly a load of crap.

[gurubuzz]

Stick it under the hood between the battery and the washer bottle and go on a long drive...to be absolutely sure wait about 1000 Km's...

Make sure you warm up the engine for a good 5 mins before you start,

[roger]

salient advice.

[warhead]

I usually wait 5 minutes.

War

[Koed]

So who started the "you gotta cook 'm for an hour" myth about tubes?
Guitar players with 20 year old tube gear?

[neilio]

brand new? it was burned in at the factory during qc....so,

as far as warm up times 5 or ten minutes should be okay....

i used to qc valve mic for well known company and there usually is a small amount of time for the system to stabilize or "warm-up" time....what i used to do when setting up a session was turn on the tube mics first,and than tape macines or board or whatever other pre=session chores i had that way i was covered.

think of it as allowing the tube to saturate itself,or "fill-up" with electrons,i know thats not technically correct,nessisarily,but you get the idea...

older circuits,or more importantly,older power supplys are where this "myth" came from, and it wont hurt a modern circuit to warm up...

that said i have used older neumanns,in particular, that seemed like they sounded their best after an hour or so of idle time....go figure.


if you really want to be anal, buy a variac and power up the supply 25% at a time interval 30 seconds per 25% increase....that could save alot of wear and tear on rectifier bridges, et al. plus a lot of older guitar amps for example seem to be happy with a very specific input voltage....old guitar guy trick.....for tinkerers variacs are really cool anyway.

someone please correct me if i am wrong.

[Whitecat]

I've been using a cheap Karma K6 ribbon for a lot of different things lately (well, some VO and some acoustic guitar, mainly) and I swear to god after an hour or two it sounds 'warmer.' Using a DAV BG-1 pre, which is pretty much always turned on unless I go away for the weekend (no power switch).

A colleague (the acoustic guitar player) was the first to notice it. So now when we work we leave the mic plugged in for a long time before we actually lay anything down.

And it's a ribbon mic...!? Does this make any sense at all? Are we actually hearing something or is this just stir-crazy studio nonsense?

[Umlaaat]

So what about leaving it on all the time?

[The Byre]

Originally Posted by Umlaaat

So what about leaving it on all the time?

Valves (tubes) and caps last a finite length of time. If you leave equipment on all the time, no matter what equipment that might be, you are using up the life span of the components. This rule applies to everything electrical, from TV sets to mixing desks.

There is a myth that switching things on and off is bad for them and therefore one must leave things on all the time to avoid their failing. This is complete nonsense!

Yes, switching things on causes some stress in the form of heat based expansion and some components such as rectifiers in PSU tend to fail on switch on because of current surge, but the root cause of that failure is the long term deterioration caused by being hot over extended periods.

Valves may have a shorter working life than solid state parts though they do seem to have an indefinite shelf life (many 60 year old tubes are still in regular use). Unlike solid state, they grow old gracefully, that is to say, they begin to distort more. In a microphone, they sound thinner and thinner as they get older.

Have a read all about it here, if you are interested -

Valve audio amplifier - technical - Wikipedia, the free encyclopedia

[The Byre]

Originally Posted by terminal3

I've been using a cheap Karma K6 ribbon for a lot of different things lately (well, some VO and some acoustic guitar, mainly) and I swear to god after an hour or two it sounds 'warmer.' Using a DAV BG-1 pre, which is pretty much always turned on unless I go away for the weekend (no power switch).

A colleague (the acoustic guitar player) was the first to notice it. So now when we work we leave the mic plugged in for a long time before we actually lay anything down.

And it's a ribbon mic...!? Does this make any sense at all? Are we actually hearing something or is this just stir-crazy studio nonsense?

I do not know the pre-amp in question, but it coiuld be that the caps are drying out as a result of having been left on all the time. The hotter it gets, the quicker they dry out.

I believe that box relies on a wall-wart for power, and those nasty boxes get very hot as well. We have several things like that in our studio and quite honestly, I hate that idea, because it means that I have to watch equipment slowly deteriorate because the manufacturer is to tight to put in an internal PSU and a switch.

When you are not using the studio, switch every thing off (after powering down of course!!!) at the wall or via the studio circuit breaker.

[Whitecat]

Originally Posted by The Byre

I do not know the pre-amp in question, but it coiuld be that the caps are drying out as a result of having been left on all the time. The hotter it gets, the quicker they dry out.

I believe that box relies on a wall-wart for power, and those nasty boxes get very hot as well. We have several things like that in our studio and quite honestly, I hate that idea, because it means that I have to watch equipment slowly deteriorate because the manufacturer is to tight to put in an internal PSU and a switch.

When you are not using the studio, switch every thing off (after powering down of course!!!) at the wall or via the studio circuit breaker.

Yes, good advice, sometimes I'm just lazy though because the BG1 has no power switch.

It doesn't use a wall-wart, though, the power supply is internal - it's just the lack of a switch! I basically pull it out at the mains when I do turn it off.