Any tricks for burn-in?

[FE911]

I was just wondering if you guys have any methods for burning in amps? Other than the tried and true(actually playing them). I remember seeing something about Matchless running them overnight after a build.
This started with a DC30 that I built for a friend of mine. He came to pick it up the day after I finished building it. He was not very happy about the harshness that it was giving out. He left it with me to see if I could do anything about it. I agreed that it was pretty harsh, almost unbearable.
So, I kept it for a week, played it quite a bit. And really grew to like it. I guess you don't notice the change if you are the one that is playing it. I called him to tell him that it was just fine, and I thought he would like it. He was very suspicious about that- considering I didn't make any changes to it. But when he came back, he couldn't believe it was the same rig. He was very happy, and still is.
And now, I would like to avoid this in the future. Not that I didn't enjoy it for the week that I had it, but he still owed me for the parts. He was a good friend, and I only charged him for materials. He's going to repay me in kind with some HVAC work(good deal considering).

[Rattlecat]

I'm still pretty new to amp building and got started over at the metro forum. What we were doing over there is pulling the power tubes and pumping dynamic music into the front end. This way at least you get the preamp caps cooked up.

[rfgordon]

I've run the stereo thru amps for many hours, with the output into an attenuator. I don't feel safe letting them run all day when I'm at work, so I keep them silent, and run them in at night. Every amp gets Larry Carlton's Last Night run thru it, just for added mojo.

Also, to soften up some speakers I'll run the stereo thru them, but I will leave them running all day, since they get pretty cranked up!

On non-commissioned builds, I also play the amps for a coupla weeks before they go to the store. But I gotta tell ya, by that time I really hate to see my babies go...

[VacuumVoodoo]

Use dummy load with at least twice the power rating of the amps output.
Feed white noise band limited to 8kHz to the input. Put the dummy load in a can of motor oil and run the amp at full power till oil smokes. No, that last sentence was a joke. Leave it on for 48hrs. Have smoke detector/fire alarm sensor above the amp.

[mhuss]

If you do the "pull the power tubes" bit, check to make sure the main B+ isn't exceeding the first cap voltage rating.

I usually do it this way, as I find little advantage to 'breaking in' power tubes and OTs (and it wastes a bit of energy), as long as you get the tubes from someone who burns them in. Some folks (e.g., Sozo) do recommend breaking in caps.

Also, smoke alarms notwithstanding, I just feel safer leaving the amp unattended that way.

--mark

[Allynmey]

I suggest and all day burn in. Leave the amp on and the volume cracked with no guitar plugged in all day long as long as you are home. Leave the speakers plugged in also so you can hear if somethings up. I would shut it off at night though. This long weekend is a great time to burn in an amp....at the end of a guitar...loud 'n proud!