The late night tube sag' question

M

mixsit

Well-known member
I been wondering about something I've observed, and was talking to a few other players about; and that's amps seeming to have less clean headroom as a night goes on, and rumors and speculations that it could be partly due to the amp's build up of heat?

Now its also reasonable that other factors are there in play that would blend in to this;
- 'we tend to get louder later' - This could be huge. Not only would we be running amps harder but there's also that thing that as the sound levels go up, so does the sound density, less space' to perceive what we'd hear as room for 'clarity.
But, being aware of that and a decent amount of experience, and taking it all into account, seems like it's more than just that.

- our ears change

- line voltage sag. I'm pretty sure I've seen this- at one venue ('venue' :p a frikin auto garage shop - the amp folding' rather hard on band peaks, and at least one other player looking around at his amp going 'WTF? But I didn't get to actually see it on a meter.
 
I think ear fatigue is a huge, often overlooked factor when people perceive their amps or whatever "changing" as a night goes on. Especially if you're playing loud. It doesn't take long for your ears to get pretty fried, and once that happens, forget it. You're not hearing things correctly. Set it while your ears are fresh and leave it alone.
 
I would have to agree with the above post. Ear Fatigue is shockingly impacting.

If u are metering and don't see a change, then that is the conclusion.

Of course it is possible issues, but u mention really isolated to the perceived reduction in clean not overall volume and allude to it being a common occurrence, which is unlikely related then to a specific amp having tube issues.

Have u tried allowing them to cool in the same session and starting again?
 
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Funny but I always thought guys like Warren Haynes and Jimmy Herring sound better in the second set. Like they have finally dialed in their tone for the night. Maybe it is ear fatigue but to me it seems like the distorted tones get more syrup-ee as the night goes on.
 
c7sus said:
Funny but I always thought guys like Warren Haynes and Jimmy Herring sound better in the second set. Like they have finally dialed in their tone for the night. Maybe it is ear fatigue but to me it seems like the distorted tones get more syrup-ee as the night goes on.
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Could be. Or maybe YOU got a more syrup-ee as the night went on. ;)
 
mixsit said:
- line voltage sag. I'm pretty sure I've seen this- at one venue ('venue' :p a frikin auto garage shop - the amp folding' rather hard on band peaks, and at least one other player looking around at his amp going 'WTF? But I didn't get to actually see it on a meter.
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I think theres some truth to this. I read an interesting article written by a guy who had a career working for big sound companies. The article was about how he thought the "good" companies had expensive variacs all over the equipment that made sure every piece of gear was getting its optimum voltage. For example old guitar tube amps like about 110v while Sound Reinforcement Power amps prefer more like 120v. and keeping that constant through out a concert is important, both for sound quality and for preserving the life of the equipment.

As the night goes on, it wouldn't surprise me that many venues suffer voltage drops that make your gear sound weak. That was the point of the article.
 
PDP said:
I think theres some truth to this. I read an interesting article written by a guy who had a career working for big sound companies. The article was about how he thought the "good" companies had expensive variacs all over the equipment that made sure every piece of gear was getting its optimum voltage. For example old guitar tube amps like about 110v while Sound Reinforcement Power amps prefer more like 120v. and keeping that constant through out a concert is important, both for sound quality and for preserving the life of the equipment.

As the night goes on, it wouldn't surprise me that many venues suffer voltage drops that make your gear sound weak. That was the point of the article.
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I'm not seeing what would cause voltage drops at venues, especially late at night. Evening hours are generally lower use than daylight hours.
 
I our case-- in this "venue" with the big sag.. (not just 'dirtier later').. the bass player bumped his head twice! -- on the car that was up on the rack behind him.. So as always.. YMMV :D

Don't know, but I would guess that if you're seeing voltage dropping (significantly enough at all?) a vaiac might not help. I.e, lack of supply, voltage goes down, turning up in a transformer -(that's what they are right?), current flow goes back up = more 'sag?
 
Lol, its always dangerous to put something in writing when you are not an expert. :facepalm:
 
mixsit said:
I guess then ruling out 'amp changes (I figured that was a long shot), we have 'ears :)
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That's really not a long shot. Ear fatigue, for me anyway, will usually cause me to turn up a bit after playing at band volume for a while. This is true no matter if I'm at practice, or in a large venue that fills with people as the night goes on, but it has never effected the amount of clean headroom an amp has, unless the amp needs a tune up.
If you are talking about a cathode biased amp, a lack of clean headroom is indicative of the beginning stages of cap failure. As they age, they dry, and their values can drift up or down. Which amp are you talking about?
 
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