critical mass ul-a2500 v2 amps are crap - diyAudio
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Old 13th October 2011, 05:30 AM   #1
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Default critical mass ul-a2500 v2 amps are crap

from the start with 4 gauge wire the cm amp would overheat and go into protection within 20-30 seconds. i was assured my setup would be fine by the sales associate i dealt with.

so, it is my impression that these critical mass ul-a2500 v2 amps are not truly 1ohm stable. i upgraded my alternator from a 150 to a 180amp. i upgraded the big 3 with 0 gauge and ran 0 gauge (replacing my 4 gauge) to the rear kinetik 2000 amp battery and to the amp per critical mass to fix the overheating issue. NO CHANGE. in one ohm with a steady 12.2 volt running to the amp it would over heat and go into protection within 20 seconds. the amp ran just as hot running at 2 ohm but never shut off. so you can buy them all day on ebay for around $600 but IMO they are worth maybe $200-250 for what you get out of them. the amp is poorly crafted. it looks like a $200.00 amp. this company is all hype, and their tech support is worthless. the box it ships in is a joke and the "manual" was literally 4 8x10 pages printed off on a black and white printer and stapled together. i also found that american bass makes an identical amp, the phantom ph4000md. google it... its the same chassis, the same side panels and connectors and very similar specs. this amp sells for $250-300. see the pics i uploaded.

stay away! dont believe the hype! buy what you know or can go somewhere and listen too. there is a reason why there is little to no info on this company or any of their amps anywhere on the internet.
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Old 13th October 2011, 06:12 AM   #2
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Did you sweep with a signal generator and find out where and what the lowest impedance really was with your speakers? How did you really determine they were 1 ohm? At that low an impedance it's really critical, hardly anything will drive a 1 ohm load but if it drops lower it's really demanding on the amp. And why do you want to when all decent auto amps now have a power supply that gives you high rail voltages. In the early days when the amp rails were really 12V it was a different story because voltage was limited, but why do you want such low impedances, just to suck every last bit of power from your amp? Well you found the truth, that most amps won't do the job. And at that low impedance you need huge speaker wire too. Why go for current instead of voltage, and get to use reasonable guage speaker wire? 2 ohm is already low, go with that and put a fan on the amp. IMHO they're crazy to give a spec at .75 ohm, the protection circuit probalby thinks it's a short (as a short would be about .75 ohm with long light speaker wire). In practical use it's probably a 2000 watt amp, not a 3000 watt amp as they claim. But for that kind of money you'd expect it to meet specs. Did you try it on a 1-ohm non-inductive non-capacitive dummy load? Did it meet spec with such a perfect load? Did you make impedance graphs of your speaker load? Are you adding eq boost near the impedance dip? What kind of speaker are you driving that needs that from one amp instead of several? For a swihcing-mode amp to put out that much heat you must be driving it pretty damn hard. Lots of money spent to not make you happy...n wonder you're pissed. But I'd recommend you go for 2 ohm and consider it an expensive 2000 watt amp. That's what, almost $3 a watt? Yeah, that's high-end prices.
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Old 13th October 2011, 06:13 AM   #3
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Geeze, the case sure looks a heck of a lot alike!
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Old 13th October 2011, 06:15 AM   #4
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Man, it looks identical!
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Old 13th October 2011, 06:17 AM   #5
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So how did it measure? What does it really put out? I can't believe some joker charges 20 times more for the same amp, assuming it is the same inside as well as out. So you got jacked for a few thousand dollars?
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Old 13th October 2011, 05:02 PM   #6
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Critical Mass have long been known for their over-hyped amps-their UL12 I have seen good things about(but $3K on one driver is ridiculous!!!), but the rest of their range seems to be re-badged "straight from China"-reasonable product at 10th the price.

Sorry you got burnt
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Old 13th October 2011, 05:12 PM   #7
djQUAN is offline djQUAN  Philippines
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If I'm not mistaken, this is the company that builds the amplifiers for the mentioned company.
SOUNDMAGUS DSP CAR AMPLIFIER

check out their K series amps:
SOUNDMAGUS DSP car amplifier
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Old 13th October 2011, 05:24 PM   #8
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Do look similar!
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Old 16th October 2011, 02:16 AM   #9
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i paid $600 for the cm ul-a2500. i bought into the hype but im not crazy enough to spend thousands of dollars on something like that!

in regards to cyclecampers posts...

im not as advanced in my stereo knowledge as you seem to be. i did test and found that i was seeing 1ohm at the amp. i have 4 fosgate p2d2 12s. so its either 4ohm or 1ohm. my thought was to buy/build a switcher so that i could run 4 ohm for daily listening and 1ohm for competition. its in my show truck so if i never got that far, no big deal, i would just stick with 1ohm as i have it wired now. i dont have the tools to do a signal sweep or to test true wattage output. i have been installing for about 16 years and have a good knowledge of stereos and how to hook them up. from past experience and using other quality sub amps as reference points (fosgate power series, earthquake, mmats, kicker, pioneer, alpine, pheonix gold, orion) i think the cm ul-a2500 was doing about 1500 watts at 1ohm maybe about 800-1000 2ohm. the amp was crystal clear and sounded great at 1ohm but i cant use an amp that shuts off after 15 seconds. there was no distortion and i only had the gain at 25%. i had all the sub settings well bellow zero on my pioneer premier headunit and i was still able to flex the front and rear windshield. i have 2-3 layers of generic dynamat lining the s-10s cab and every panel waved as if there was no sound deadening. so for 300.00 this amp would be a great unit running 2-4 subs at 2 ohm. i have recently bought a fosgate t1500-1 bdcp and am in the process of hooking it up. i have a t400-4 coming in on tuesday for the mids and highs. this amp to my understanding basically handles 1 and 2 ohm the same so i shouldnt have the huge power inefficiencies i was seeing with the cm amp. the reason i want to run 1 ohm was because i have 4 dual 2 ohm subs. my original plan was to get a second earthquake d2 and run two subs off each d2. that plan fell through. so now im trying to run at 1ohm off one amp. the t1500 is prolly more than i need but i plan on getting 4 15s or two 18s in the future. at a shop they are running 9 fosgate p2 15s off one of these t1500s and sounds great. it was a toss up wether to buy the t1500 or a sundown 1500 but it seemed like the sundown had higher power consumption needs. i really dont want to put anymore money in or tear the interior out yet again for power upgrades.
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Old 16th October 2011, 12:42 PM   #10
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4 2-ohm subs...I'm assuming 2 channel bass, for each channel the choice is 2 2-ohm in parallel for 1-om load or 2 2-ohm in series for 4 ohm load.

1 ohm is really hard to drive and requires heavy speaker wire. I prefer parallel because series makes the driver anomalies interct, but unless you have another amp or buy another of these you have to live with the reduced output with 4 ohm, since it won't actually drive the 1 ohm anyway. If they're really identical, but the cheaper one and run 4 channel bass, one amp channel to each sub, but you might blow the speakers. For daily use, I'd just go 4 ohm and enjoy the improved reliability; still plenty of output if you're bending glass.
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