P.A. 18 TH (18tbw100 30x38x22.5") - Page 3 - diyAudio
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Old 14th September 2013, 01:51 AM   #21
sine143 is offline sine143  United States
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Alright. This puts me back to the drawing board. 110V on the table
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Old 14th September 2013, 02:05 AM   #22
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Originally Posted by sine143 View Post
Alright. This puts me back to the drawing board. 110V on the table
Not exactly sure what you're getting at, but IMHO a 15A or 20A 115v breaker is more than enough for a very powerful class-d sub amp when just playing music (aka not sine waves). I've run the NU6000 plus a 200w/ch class AB mains amp and PC/dj gear off only 15A 115v without a problem. You could probably run two nu6000's off a 15A breaker successfully if you really wanted to push your luck.

However, next time out I may try to put the amps on separate breakers just to see if it helps incrementally. I specifically have my main long power runs on 12g cable to minimize loss, including a 20A rack mount power strip that is internally and externally 12g wire, modified with a 15A plug. (it is ok per code to use a 20A breaker and 12g wiring for 15A outlets, so you will see that occasionally)

Last edited by turbodawg; 14th September 2013 at 02:24 AM.
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Old 14th September 2013, 02:06 AM   #23
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Breakers can temporarily pass 10x their amperage rating
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Old 14th September 2013, 02:25 AM   #24
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Originally Posted by m R g S r View Post
Breakers can temporarily pass 10x their amperage rating
Yes! Switching power supply amps pull spikes far over the breaker rating during normal operation.
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Old 14th September 2013, 10:24 AM   #25
sine143 is offline sine143  United States
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I regularly see voltage drops down to 100v or less according to system architect running my crown xti 4002 on a 10 gauge 20 foot drop cord straight into 20 amp circuits. Limited at 60v with a 4 ohm load. Ive blown plenty of 15 amp breakers when running 3 subs per side even limited at 50v output.

When i said back to the drawin board i mean most of the FlH id been working up in horn resp hit 12mm xmax with the tbw100 at about 90v. 110v into 8 ohm reflects the 1500w aes rating, and if im good to sim to 20mm i should jave nonproblem keeping it in check even with 110 volts input
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Old 14th September 2013, 12:09 PM   #26
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That's why I like heavy old school amps for sub duty on limited amperage

With the switching power supply when line voltage drops they pull a ton of current
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Old 14th September 2013, 12:11 PM   #27
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Xmax plus 8mm is a bad number to shoot for IMO. I'd shoot for right around rated Xmax, maybe a mm or two higher without worries.

At Xmax plus 8mm distortion must be very high.
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Old 14th September 2013, 01:27 PM   #28
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Originally Posted by m R g S r View Post
Xmax plus 8mm is a bad number to shoot for IMO. I'd shoot for right around rated Xmax, maybe a mm or two higher without worries.

At Xmax plus 8mm distortion must be very high.
On a driver with a conservatively rated xmax, I'd say half way between xmax and xmech is fine in a low tuned bass reflex design. A small amount of extra sub distortion will not be noticeable IMHO, masked by the music. It will only be in two short frequency bands where possible excursion is that high, and since we are talking about a lower tuning, there will be less stress than if this excursion occurred at higher frequencies. In the odd case of a sustained bass note, you're more likely to pick up on massive room rattling.
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Old 14th September 2013, 01:54 PM   #29
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Originally Posted by sine143 View Post
I regularly see voltage drops down to 100v or less according to system architect running my crown xti 4002 on a 10 gauge 20 foot drop cord straight into 20 amp circuits. Limited at 60v with a 4 ohm load. Ive blown plenty of 15 amp breakers when running 3 subs per side even limited at 50v output.

When i said back to the drawin board i mean most of the FlH id been working up in horn resp hit 12mm xmax with the tbw100 at about 90v. 110v into 8 ohm reflects the 1500w aes rating, and if im good to sim to 20mm i should jave nonproblem keeping it in check even with 110 volts input
Interesting. 50v on 2.6 ohms (3x 8ohm nominal) figures to 940w (x2), so I would have to think that the load in question was well below that? 3x 4ohm subs in parallel? Figure the amp should be around 80% efficient, and supplied power should be at least 1/3rd of nominal output? Maybe if you're sustained hitting notes that are right at an impedance minimum? Horn subs, if that's what you have, have a more challenging impedance plot and should be harder to drive.

My comments about excursion don't apply to horns, only bass reflex where loads on the driver are not as severe.

Last edited by turbodawg; 14th September 2013 at 01:58 PM.
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Old 14th September 2013, 03:27 PM   #30
sine143 is offline sine143  United States
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Its a popular 3015lf FLH. Suppossedly a 10 ohm nominal boxIts heavy bass music , almost pure sines in the 35-60range.
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