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Is plugging a head into a power conditioner bad?

#81
In general, do not use large amps with voltage regulators.

In general, quality amps include adequate protection and filtering for all reasonable applications.

In general, do not use the power switch on typical power conditioners to switch on and off large power amps.
 
#83
Ok, I'll bite....

I have the furman regulator, its a multi-tap voltage regulator, how does that starve gear for current?

My understanding is this: If the voltage goes down, a different tap is used, to bring up the voltage. Its still a transformer, it will pull more current from the wall to maintain the same power at the lower input voltage. But essentially that's the same as using a different transformer (or different tap on same transformer) that an amp manufacturer might use to make it easy to switch an amp between US 120v and EU 240v lines. Only it does it automatically over a much smaller voltage range.

Is there additional circuitry that limits the current, cause I don't see how an autotransformer would do that?

On an anecdotal note, we played an outdoor festival once, kind of homegrown by the local businesses. So power was supplied through a couple of loooong extention cords plugged into an outlet in the basement of the building next to the stage... :rollno:

Obviously the cord was too long, and insufficient size to handle the load. I know this because whenever I nailed a low B, I could see the voltage indicator light swing down to the left on my furman power regulator... :D I could drop it at will, down to around 105 from 117 at idle.. I could make it dance like a VU meter.. That's the only time it ever did anything useful as far as I can tell. All the hype over "low voltage, bad bar wiring/power" seemed unfounded. Never recall any other instance where the power was not btw 110 to 120v and stable.

As far as "power conditioners" go, I agree, waste of money compared to a decent outlet strip with MOVs. Amps run on DC, they have their own internal regulated supplies, you can use something to protect them from surges caused by lightning strikes and that sort of thing. The MOVs take care of that. But AC line "noise"? I don't buy it. That seems unlikely to survive rectifying, smoothing by the capacitors, then adding some circuitry to regulate the resultant DC voltage. Any high freq noise will be effectively shorted to ground by the huge supply capacitors.

If there's "noise", its more likely stray EM that gets picked up by poorly shielded cables, or pickups rather than coming in through the AC line and surviving the trip through the power supply of the amp.

Randy
 
#84
Voltage regulators can hunt or oscillate due to interaction between the dynamic load (an amp) and the high source impedance (long extension cord or inadequate building wiring). When they oscillate, they can fail and they can also generate zipper noise when changing taps. The big question is where to change on the AC power waveform... do you change at zero voltage crossing or zero current crossing? The best solution will vary depending on the power factor of the load.

Here's what happens when the system becomes unstable:

Long AC power wiring causing voltage drop that increases as current demand increases.

The voltage regulator taps up the voltage which causes more current to be drawn which further decreases the incoming voltage then all of a sudden the current being drawn buy the amp decreases quickly, the tap changer zips down but as it zips down the voltage drop decreases on the supply cable and it has to zip below where steady state would have been and as it's doing this suddenly you get another current demand and the voltage drop increases causing the tap changer to play catch up and it constantly has to overshoot because there is a component of positive feedback that must be delt with. Generally they slow the control loop down to where it's stable under most conditions but there is always this lurking behind the scenes. Generally, they work well for fairly static loads as the control loop isn't being swung all around.

If anybody has a real need for one of these, I have a few that are currently surplus but I do not recommend them for power amps.
 
#85
agedhorse said:
Voltage regulators can hunt or oscillate due to interaction between the dynamic load (an amp) and the high source impedance (long extension cord or inadequate building wiring). When they oscillate, they can fail and they can also generate zipper noise when changing taps. The big question is where to change on the AC power waveform... do you change at zero voltage crossing or zero current crossing? The best solution will vary depending on the power factor of the load.

Here's what happens when the system becomes unstable:

Long AC power wiring causing voltage drop that increases as current demand increases.

The voltage regulator taps up the voltage which causes more current to be drawn which further decreases the incoming voltage then all of a sudden the current being drawn buy the amp decreases quickly, the tap changer zips down but as it zips down the voltage drop decreases on the supply cable and it has to zip below where steady state would have been and as it's doing this suddenly you get another current demand and the voltage drop increases causing the tap changer to play catch up and it constantly has to overshoot because there is a component of positive feedback that must be delt with. Generally they slow the control loop down to where it's stable under most conditions but there is always this lurking behind the scenes. Generally, they work well for fairly static loads as the control loop isn't being swung all around.

If anybody has a real need for one of these, I have a few that are currently surplus but I do not recommend them for power amps.
Click to expand...

Ya know, if I had the time to read more of your posts I would actually gain some real knowledge here. I may have to make a point of it - great stuff above and quite understandable. Light years ahead of my high school electronics teacher. :cool:
 
#86
agedhorse said:
In general, do not use large amps with voltage regulators.

In general, quality amps include adequate protection and filtering for all reasonable applications.

In general, do not use the power switch on typical power conditioners to switch on and off large power amps.
Click to expand...

Thanks! I guess that's kind of like saying "take an aspirin and call me in the morning if it doesn't get better"...... :D
 
#88
groooooove said:
your right about the scratches, but a clean vinyl certainly sounds more robust and "fat" than a CD, but does also have a darker high end. but thats totally a subjective "like or dont like" thing.
Click to expand...

Maybe to you. I disagree. To my ear there's absolutely nothing more "robust" or "fat" about an LP. I like the sound of CDs every bit as well as he sound of LPs, and there is no contest in terms of durability. Play an LP a very few times on the average turntable and the sound has already gone downhill. CDs will sound the same 10 years from now as they do today, even if they're played every day of that 10 years.

LPs are an outdated technology that I've pretty much abandoned. I have some that are still not available on CD, but I'll transfer them when I have time.
 
#89
esoxhntr said:
Ya know, if I had the time to read more of your posts I would actually gain some real knowledge here. I may have to make a point of it - great stuff above and quite understandable. Light years ahead of my high school electronics teacher. :cool:
Click to expand...
i have to say andy goes over my head sometimes, but he's really good at dumbing down his replies when he leaves me in the dust, and then i can go back and reread the more complex version and get what he's talking about. it's a real gift.
 
#92
Sartori said:
I just plug my amp into a surge protector power strip and call it done.
Click to expand...



Except my surge protector can be mounted in my rack case and has a re-set (yours may too, I dunno), has lights so I can see the controls on my amp, wireless, tuner and compressor, gives me a read-out of the voltage and allows me to set up my rig in under a minute, while keeping everything neat and out of the way and protecting the PA and my bass amp, as well as providing a common ground.

My surge protector is a Furman Series II with SMP. I can't believe how expensive these have gotten, but I bought mine for $89.00 (plus shipping) a few years ago. I had ordered the plain-vanilla version, but the eBay retailer I bought it from was out of them at the time, so they sent me the one with the digital voltage read-out - for the same price. Sweet!

My stereo has an API power conditioner that actually does have transformers to isolate the components, but it also has outlets for amps, which don't have transformers. I plug my 150 watt/channel (doubling into 4 ohms) power amp into one of those. Everything else gets one of the digital or analog isolation outlets. I can tell no difference between those (amplifier) outlets and plugging into the wall, including playback at high volume levels.

BTW (and for the record:cool:) my VPI - Rega - Benz Micro analog rig cost about $2500.00 when new (mid '90's). It always sounded better than the $3700.00 full-bore Audio Alchemy digital playback system (also from the mid-'90's). But that finally died (CD players seem to have a shelf-life which record players don't), so I bought the $1500.00 CA Azur 840C CD player and I'm very happy with the sound I'm getting from digital. With the proper recording, it's getting hard (but nowhere near impossible) to tell them apart. But with most CD vs. LP comparisons, the analog system still trumps the digital, especially in the amount of separation of images and their dimensionality. What I'm saying is that, while the price of a decent analog rig has stayed more-or-less constant (~$3000.00), the price of good red-book digital playback has been falling. It used to be that to compete with a modest LP player, CD players had to cost in the range of $10,000 -$15,000. That number is down to about $4000 - $5000. And high-res digital formats, while sounding slightly different than analog, sound just as pleasing and "real" in terms of ultimate listening pleasure. We're actually well into a "golden age" of CD (44.1K, 16 bit) products.
Of course, some may not be able to hear a difference between the two, or may not have the best speakers or amplification with which to make the comparison.
 
#93
Bluesbob said:
My stereo has an API power conditioner that actually does have transformers to isolate the components, but it also has outlets for amps, which don't have transformers. I plug my 150 watt/channel (doubling into 4 ohms) power amp into one of those. Everything else gets one of the digital or analog isolation outlets. I can tell no difference between those (amplifier) outlets and plugging into the wall, including playback at high volume levels.
Click to expand...

:eek: A couple of their statements might explain why...

http://www.audiopower.com/newsite/FAQ/whybuy.html

http://www.audiopower.com/newsite/FAQ/breakin.html
 
#99
Sten said:
So does it really protect from any surges, or is it basically just a power distributor?
Click to expand...
Yes to both. As with so many items that are even the least bit technical in nature the advertising for it intentionally plays on the consumer's lack of understanding as to what it actually can, or can't, do.
 

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