tube amp info

I'm not sure, but I beleive that the volume settings on the pre-amp for two different amplifiers will vary with the impedance of the amplifiers in question. As you play your amps more, you will notice a point during warm up in which everything just sounds better (typically about 30-45 minutes), I don't believe there is any harm playing at volume sooner, but a properly warmed up unit does sound better. I'll typically turn my system on early before anticipated listening just to allow for warm up. (Pre-amp first, and amps after the pre-amp has reached operating temperature (usually about a minute). I'll also turn on source components to allow them to warm up also. When turning the system off, amplifiers are turned off first, before turning off the pre-amp. (Essentially, your pre-amp should be in powered up and in control of your system from start up to finish). I hope this helps, Happy Listening,

The amps input sensitivity will determine how loud it will sound given the same output signal from a pre-amp. I don't have a formulae for calculation but for example using the same pre-amp with an amp w/ an input sensitivity of .5v I get a couple of clicks less on the volume pot (probably 6db or so) than I would when connected to an amp with an input sensitivity of 1v which is again a couple of clicks lower on the volume pot than I would get if the amp had an input sensitivity of 1.5v.

You can play at substantial levels shortly after you turn your stuff on, BUT it may sound a bit rough/harsh/cold. I usually turn everything on and put on some background music for 30 minutes or so while I do other things.

I agree with the above posts also. Do give you tube amps time to warm up. You dont want to start palying music through a amp just turned on as you risk tube damage by stripping the anode (plate)/ within the tube. Give about 5-10 mins at least.--Ken

Assuming you have a high quality, revealing system, I vehemently disagree with the above posts. All of your equipment except the tube amps should be left on 24/7 and powered down only if there is an electrical storm (in which event everything has to be unplugged, not just turned off). A high-quality system will not sound anywhere near optimal if the equipment is cold -- as a general rule, circuits take many hours to stabilize, especially digital (at least twenty-four hours as a general rule). And just so there is no misunderstanding, this advice also holds true for tube preamps and other equipment using small signal tubes -- the small signal tubes in tube preamps, tube CD players and tube tuners pass very little current, and the studies done in the 50's proved conclusively that they last much longer and sound better if left on 24/7 so they are not subjected to the deleterious thermal cycles that occur when they are turned on and off.

Tube amps should generally not be left on 24/7 because the output tubes pass a lot of current and they will wear out relatively quickly. There is also a safety issue, as most tube amps do not have tube shut-down protection circuits. I have VAC Renaissance 140/140 monoblocks, and the output tubes require three to four minutes to come up to temperature. I do not drive the amp with music until they have been on a good hour, however, as it takes at least that long for the rest of the amp to come up to temperature (the VAC's are a hot-running, class A design).

If you have budget equipment or object to leaving equipment turned on for environmental reasons, then turn everything off. But if you have good equipment that you don't want to break and that you want to sound its best, leave everything but the tube amps turned on and give the amps fifteen minutes to a half an hour before playing music.

Just to give my two cents worth. I would not leave any tube equipment on 24/7 especially amps and pre-amps. SS pre-amps are fine left on 24/7 as are ss cd players; I would not leave ss amps on 24/7. I have all CJ components (tube pre and ss amp) and this is their recommendation as well. My cd player is a Sony SCD-1 and I even turn it off.

Chuck

Well, if you're supposed to turn your amp off before your pre, how do you turn your tube preamp off if you were leaving your SS amp on?

Quoting from the "TIPS & ADVICE" section of the owner's manual to my VAC Rennaisance 140/140 Mk. III tube amps:

"How long should tubes last? It has long been known in professional circles (and probably now forgotten) that a [small signal] tube such as the 12AX7 will display BETTER performance characteristics after TWO YEARS of CONTINUAL operation than when it was new. In normal use it is not unusual for a low level tube to last 5 years or longer. Output tubes [i.e., power tubes used in tube power amps] are another story, as they are continuously providing significant amounts of current." (Emphasis original).

Well here is another 140/140 owner needs to retube the 300B's (16) soon. Are the EH gold grids a decent choice.