critical mass ul-a2500 v2 amps are crap

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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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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.
 
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.
 
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.
 
i think the cm ul-a2500 was doing about 1500 watts at 1ohm maybe about 800-1000 2ohm.

from the link I posted, the Soundmagus' DK1800 is about the same size as your UL-A2500. Comparing the power rating, the DK1800 is 1800@1R and 1000@2R which is just about your estimate so I'm guessing they are the same amp. In other words, CM probably over inflated their published power ratings. :no:
 
i sold the cm ul-a2500 and bought the rf t1500-1 and a t400-4. i wasnt gonna run this setup at four ohm and be unhappy and i sure as hell wasnt gonna buy another cm. i was just letting others know to stay away and that there are other amps out there that may be identical for far less money. these cm amps have been selling pretty steady from the company i got mine from on ebay and when i searched for info before i bought mine there was pretty much nothing out there. so my goal is to get the word out.

this amp would be great for $280 or less and these others that look similar (similar specs and same chassis) are in that price range. they may have the same guts.

the subs i have dual 2ohm voice coils so yeah its 4 or 1. thats why i went with the fosgate. it supposedly handles 2 and 1 ohm the same. we'll see. you know how to make or where to buy a switch (i've read about them) to wire everything up and switch between 4 and 1 ohm?

oh and i'm running 10 gauge to my subs.
 
If you are running the amp bridged and applying that 1 ohm load then both sides of the amp see it as a 1/2 ohm load. If you are bridging it you will need to wire the speakers at a 2 ohm load and in bridged mode it will appear to the amp as a 1 ohm load and if it is truly 1 ohm stable then it will not shut down. If it is 1 ohm stable then you can apply a 1 ohm load to each chanel in stereo mode andit will be seen by the amp as a 1 ohm load in stereo mode because the channels are not combined. All bridgable amps work this way.
 
brian oshman,

i get what your saying, though reading some fosgate forums suggest otherwise for the t1500-1. they say that its wired in parallel inside and that running it like you would to bridge, 2 wires for four subs, results in the same output as running four wires, splitting two subs and two subs with each pair showing 2ohm.

the cm seemed to work like you mentioned, although it still went into protection after 10-20 seconds either way. both the cm and fosgate do not show any mono channel markings though and neither show any diagrams for this type of install in their manuals.

dj quan,

i totally agree with you. i would bet money they are the same amp. id be interested to try one of the sound magnus amps. two of those for 250 a piece running both at 2 ohm would sound fantastic if they are indeed the same as the cm amp. its a shame that the cm wasnt really 1ohm stable. it did sound great and had a TON of power for its tiny chassis but the inefficiency was ridiculous. you would need 2-4 kinetik 2000 amp batteries and a 300 amp alternator just to run it. with that kind of setup you could go with some sundowns or mmats for the same money and have way more bang for the buck.

i also have no idea where to start on making a 1ohm to 4ohm switcher. from what you said, it almost sounds like a fire waiting to start if its not perfect.
 
i dont know why u posted the american bass ph4000md is not anything like the cm amp i had the cm it was junk, i am now running the 4000md at 1ohm with 4 gauge power wire to 2 12 inch american bass xfl subs and the amp has been tested pushing 2,100wrms @1ohm.amp does not even get warm i have played it on a 3 hour trip last week not a issue.i would tell any one to get the american bass audio stuff is sweet and not high in price. i have had every kind of amp u can think of from sundown to ppi.hands down the best for the money
 
The Rockford is a mono-cannot be "bridged", they put two pairs of speaker terminals on them so you can fit more speaker wire into the amp if you're running multiple subs, so the terminals are "paralled" inside the amp-so you won't be running it a 1/2 as some have stated.

Rather than a switch you could simply use banana plugs, would be easy enough to swap them around to parallel/series the drivers.
 
Well i bought both the ul2500 and ul 800 from ebay, got both new for around 1700 together, i saw this bashfest after buying them and i will update when i actually recieve and install them. I do have a sinking feeling in my stomach now, but w/e we live and learn i guess.
 
Rich65

I don’t know your setup but don't freak out, I had the same Critical Mass UL2500 v2 with 2 CM 12s in parallel at 1 ohm and never had a problem. As a matter of fact it was probably the best Sub amp setup I ever had. It was incredibly loud and ran cool. The bass was clean and powerful without any voltage noise or fluctuations and it never shut down, ever. However I did use the 2500 with new CM subs. My setup was new CM subs new CM amp, so I know the Subs where 1.6/coil (through DMM) and .8 ohms in parallel.

As to the problem in the post, MANY MANY years ago when I worked in the car audio shop we had lots of people that brought systems with used Subs that sounded fine at low levels and seemed fine when tested with a DMM, but would cause the more powerful amps to shut down because the Subs would only short at high excursion. When those Subs where replaced the system never shut down again. This means that less powerful amps would not cause the short because in that particular problem it would only short at about 2KW.

PS: I paid over $1200 for the UL2500v2, I replaced 2 JL 1000s which I sold for about the same. At the end I ended up with a much better Sub system but because I also changed the subs from JL to CM I can’t do an exact comparison because the JL Amps were not used on the CM 12s. What I can tell you is that 2 SS12s and one UL2500 sounded much better and louder than 1 JL 13W7 with 2 JL 1000/1v2. As to the other brands that are mentioned here I have not heard of them and never used them, but for the 1 Day that I connected the CM 2500 to the W713 I can tell you that the CM UL2500 it’s more powerful than both JL 1000s together. About 1.5-2DB louder.

Good luck with the install if its anything like mine was it will rock.
 
IDK American trading laws, but in the UK if you buy online you have 7 days to cancel or in the event you have received the goods 7 days to return them for a full refund (less postage costs). If it's a private seller on ebay IDK what the rules would be, I'd guess whatever they stipulated in the ad.
 
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