When doing sound for a festival, the event is usually outside and often powered from generators.
As virtually all pro sound equipment is solid state are there any products that have special issues from the generally lower quality of the AC power.
For example Hammond organs tone generator is tied to the frequency of the AC line. So special modifications are required to insert a stable frequency standard.
Some folks swear the guitar amplifiers must be tube designs for best results, other folks insist on solid state units.
Anyone have actual experience with these issues?
As virtually all pro sound equipment is solid state are there any products that have special issues from the generally lower quality of the AC power.
For example Hammond organs tone generator is tied to the frequency of the AC line. So special modifications are required to insert a stable frequency standard.
Some folks swear the guitar amplifiers must be tube designs for best results, other folks insist on solid state units.
Anyone have actual experience with these issues?
The frequency depends on load, so as the engine changes speed with load, variations do occur in frequency.
That may not be an issue in a brush less design with electronic commutation to control frequency.
Also, our generators are generally diesel, and there is a din in the area rather than silence when a sound truck passes, so fidelity, or lack of it will not be an issue, in my opinion.
Bear in mind that the listening conditions will not be ideal, the speakers will be PA grade rather than hi fidelity, traffic noise and sound from other performers may be there.
I will post a photo later, 15 - 25 kVA generator driving 7 amplifiers, each the size of a computer case, and many speakers, on a farm tractor trailer, flashing lights too.
Thumping bass, screechy treble, enough to give you a body massage, and things to fall of your car dash top, if you are close.
Fidelity, in such conditions, is not expected.
The amps used here are Mosfet units, with SMPS, no effect from minor input frequency variations, and now mostly FM modules with USB stick as storage, to play recorded music.
That may not be an issue in a brush less design with electronic commutation to control frequency.
Also, our generators are generally diesel, and there is a din in the area rather than silence when a sound truck passes, so fidelity, or lack of it will not be an issue, in my opinion.
Bear in mind that the listening conditions will not be ideal, the speakers will be PA grade rather than hi fidelity, traffic noise and sound from other performers may be there.
I will post a photo later, 15 - 25 kVA generator driving 7 amplifiers, each the size of a computer case, and many speakers, on a farm tractor trailer, flashing lights too.
Thumping bass, screechy treble, enough to give you a body massage, and things to fall of your car dash top, if you are close.
Fidelity, in such conditions, is not expected.
The amps used here are Mosfet units, with SMPS, no effect from minor input frequency variations, and now mostly FM modules with USB stick as storage, to play recorded music.
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I did Concerts In The Park one year. Mostly on a cheap gasoline generator the city had in the sewer department. My main change was to ALWAYS use a voltmeter and watch it. Unloaded it tended to be high but one (180W) tube amp idle got it down to 124V. With over a kilowatt of PA and band it like to be 112V which is fine. In a lot of the world, 140V peaks and 90V dips are normal.
I never monitored frequency except by feeling my PTs for excess heat. Large 60Hz PTs tend to stand 50Hz very well (ample inductance), though small wall-warts can melt if the frequency drops low. My 3.7KW propane generator only varies a Hertz or two, except when my well-pump's 5.5KW starting surge happens. Don't share with oversize hard-start loads. (This would include a window A/C in your mix shed.)
I never monitored frequency except by feeling my PTs for excess heat. Large 60Hz PTs tend to stand 50Hz very well (ample inductance), though small wall-warts can melt if the frequency drops low. My 3.7KW propane generator only varies a Hertz or two, except when my well-pump's 5.5KW starting surge happens. Don't share with oversize hard-start loads. (This would include a window A/C in your mix shed.)
For me, outside (parks -squares - beaches - tourist areas - etc.) powered by cheap cheesy terrible gasoline generators is an everyday reality.
FRorget real Hammonds, in any case excellent sampled database keyboards are available.
Small tube amps are possible, 1or 2 large ones hog much of available power which should be reserved for PA
Tube amps suffer much more than SS ones, because besides the direct voltage>power relationship also suffered by SS ones, they are also unduly sensitive to inevitable *filament*voltage variations.
As in: 20%-30% mains voltage drop affects tube amps a lot, makes them fuzzy and anemic, while SS ones "simply don´t get as loud" , no big deal.
Now on the other side, given our Geographical position and typical Customs problems, lots of cheap generators available here (which get bought because of the low price) are NOT Argentine Mains approved ones: 220V -50 Hz , but "grey market" ones: bought for peanuts in Miami or Panama.
You will find actual 240V 60Hz ones 😱 , which typically under light load (such as when nobody is playing) put out scary 260V or higher, once in a local "Charity" festival amps started to pop like fire crackers ... I measured 280V at the portable terminal strip where they were plugged in 😱
Some amps take it (Peavey, Fender, Laney, my own),some blow up.
Either outputs short or caps pop their caps, if I can say so 😉
Literally. 🙄
FRorget real Hammonds, in any case excellent sampled database keyboards are available.
Small tube amps are possible, 1or 2 large ones hog much of available power which should be reserved for PA
Tube amps suffer much more than SS ones, because besides the direct voltage>power relationship also suffered by SS ones, they are also unduly sensitive to inevitable *filament*voltage variations.
As in: 20%-30% mains voltage drop affects tube amps a lot, makes them fuzzy and anemic, while SS ones "simply don´t get as loud" , no big deal.
Now on the other side, given our Geographical position and typical Customs problems, lots of cheap generators available here (which get bought because of the low price) are NOT Argentine Mains approved ones: 220V -50 Hz , but "grey market" ones: bought for peanuts in Miami or Panama.
You will find actual 240V 60Hz ones 😱 , which typically under light load (such as when nobody is playing) put out scary 260V or higher, once in a local "Charity" festival amps started to pop like fire crackers ... I measured 280V at the portable terminal strip where they were plugged in 😱
Some amps take it (Peavey, Fender, Laney, my own),some blow up.
Either outputs short or caps pop their caps, if I can say so 😉
Literally. 🙄
Yes, you're right! You'd use either a frequency regulated generator for general power supply or a frequency conversion unit built into the organ, such as the Trek II SC-60D.
Definitely no! Although there are some really good clonewheels nowadays, there's no such thing as the REAL thing 😉 !
Best regards!
I can't decide if Ed is funning us again or not as the elder statesman of sound in difficult circumstances 😀
For the purist? Sure!!!
And I LOVE the real thing too.
Coming from the late 60´s early 70´s on, way back then I was SURROUNDED by them, nobody wasted a second complaining about the weight and inconvenience.
Full ones, cut-in-two, you name it.
It was the Golden Era of Deep Purple, Symphonic Rock, Kansas, ELP, plus tasty Jazz and Blues players.
I was well known then for converting 60W tubed Leslies to my own 200W SS amps driving an EVM15L or a Gauss speaker.
Musicians also used "real thing" Mini Moogs and Solina String Ensembles, plus Fender Rhodes and Clavinets.
But then sampled keyboards took their place, specially in small venues which would be gasoline generator powered; Stadium filling big acts are something else 🙂
Hey, one of my customers even used a real hanging-tape Mellotron!!!!
Now talk about a PITA keyboard if I ever saw one!!!
But then an University Symphonic Orchestra came with a problem: when playing in full strength, at an Opera House or large Theater, etc., they went all the way, moved whatever was necessary, etc. , but now and then they were called for smaller private gigs, where only a sub-section went, say 8 to 12 Musicians.
Each drove his own car, all plain dressed in black pants and shirt, etc.
No big problem except for the piano player.
He bought a killer sounding Kawai electronic piano, which included samples of World famous ones, say the Milan Scala one, the works.
But everybody looked at him sideways, as if he were cheating 🙄
So I asked them to bring an empty vertical piano, once you pull the cast iron "harp" and the original keyboard and mechanism, it becomes easy to move around by just 2 people, no wheels or carts needed.
Then I made a "bed/shelf" to install the Kawai keyboard (which is exact size and shape of original keys assembly but made out of lightweight plastic), a hidden Stereo 2 x 50W amplifier and 4 hidden full range speakers, 2 per side, firing sideways and downward.
When Pianist was playing, you heard a real Piano, sound actually CAME from the Piano, and we did not overdo it, volume was setup matching what an unamplified Acoustic one would put out.
The illusion was perfect and everybody was happy.
Been running speakers, amps, computers, lamps and DJ equipment of various sorts on different kinds of generators.
When using the basic kind of petrol generator and running out of gas or having it turned off without turning off the power I broke a laser once, otherwise I haven't had any issues really.
However it is easy to run out of power, especially for handling peaks, making the sound suffer. You cannot really compare 16A from a generator with 16A from an outlet when it comes to how much peak power can be provided. Also some generators need a constant load, so usually have some 400w UV canons to help with that. Nowadays I always get the largest diesel generator I can find. The 40kVA Atlas Copco trailer are not that expensive to rent and gives nice stable power.
When using the basic kind of petrol generator and running out of gas or having it turned off without turning off the power I broke a laser once, otherwise I haven't had any issues really.
However it is easy to run out of power, especially for handling peaks, making the sound suffer. You cannot really compare 16A from a generator with 16A from an outlet when it comes to how much peak power can be provided. Also some generators need a constant load, so usually have some 400w UV canons to help with that. Nowadays I always get the largest diesel generator I can find. The 40kVA Atlas Copco trailer are not that expensive to rent and gives nice stable power.
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Yes and yes. In contrast to a real TWG Hammond, which, despite of it's electromechanical complexity, is rugged gear, Mellotrons are rather prone to fail, even during gigs. So they are being replaced by electronic machines that use already sampled sounds from original Mellotron tapes, even reproducing the limited tone duration time of just eight seconds.
Best regards!
Thanks guys, so I will just avoid tubes for the guitar amps.
Actually have three Hammonds in the back rental stock. One with the frequency standard. Unfortunately the local Hammond repair wizard passed away a while back. He was wonderful in his ability to repair and upgrade Hammond organs.
I do keep a fueled and working AC generator in the back, but that is for the sump pump if the stream by my lot rises above it’s banks. I wouldn’t think of using a cheap generator like that on electronic equipment.
The other fun bit about backline is that around here the British bands travel with 220 volt gear and require step up AC power transformers. That is not a problem except when someone shows up with the really cheap ones. They tend to fail with shorts to case or ground, etc. Interestingly enough, most of the dangerous units are not made in China, just south of there.
The other issue is that when the traveling bands blow a fuse, they are often surprised to learn around here fuses are normally 3AG not 20mm. However I do keep a stock of 20mm ones.
Actually have three Hammonds in the back rental stock. One with the frequency standard. Unfortunately the local Hammond repair wizard passed away a while back. He was wonderful in his ability to repair and upgrade Hammond organs.
I do keep a fueled and working AC generator in the back, but that is for the sump pump if the stream by my lot rises above it’s banks. I wouldn’t think of using a cheap generator like that on electronic equipment.
The other fun bit about backline is that around here the British bands travel with 220 volt gear and require step up AC power transformers. That is not a problem except when someone shows up with the really cheap ones. They tend to fail with shorts to case or ground, etc. Interestingly enough, most of the dangerous units are not made in China, just south of there.
The other issue is that when the traveling bands blow a fuse, they are often surprised to learn around here fuses are normally 3AG not 20mm. However I do keep a stock of 20mm ones.
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