Pro audio power amps

Interesting... check out page 9, a Powersoft K20 is used in the Large Hadron Collider. In what capacity I'm not exactly sure, but still cool:
https://cds.cern.ch/record/1232062/files/CERN-TE-Note-2010-001.pdf

 

very interesting way of using an amplifier i think. looks really cool. i remember reading where the old crowns were picked on for being arc wleders and were used for powering large power tools and extra construction accessories.

 

I wonder what kind of amps they used for those singing tesla coils... (not sure if that's even applicable)

 

the crown xti 4002 is one amp that proved itself to me. i had it for a year now just about and it never failed on me ever. even slamming nominal 1ohm loads it never overheated and ran super cool. it will pop a 20a circuit before giving out under heavy loads. also the input eq(before crossover) and output eq(after crossover section) with adjustable q filters and limitless frequency designation had been very useful. i can say this is one amp that i think to myself that it's worth every penny that i owned and very satisfied with it. it is too one amp that never blew outputs or anything under heavy loads and being stressed out. i ran a 15hz sinewave through the amp at 1ohm nominal load at a consent near clipping point for 40 minutes in room temperature and the psu stayed at a cool 45c....try doing that with a krell amp.... good job crown. good job.

 

Have you ever heard of the Crown LPS series? There's a local seller with an LPS 2500, but I can't seem to find much online. Judging from pics and specs, it looks to be related to the XLi series?

 

Yea, it looks exactly a like. Seems be uk version of the amp cause some crowns weren't exactly universal and Europe/uk has strict regulations bout banana plugs and input connections. Also crown never made universal power supply switches really till the xls class d series and them switching over to smps units...

I actually like the look of the lps to the xli. Kinda has a new ashly look vibe to it in a way...

 

Do you have any experience with the XLi series vs the XTi?

 

sadly i don't. i only have used micro/macrotech, CE series, XLS drivecore and XTI2 series... never had issues with either. i looked at the xli before since even new you can get them cheap at local store that still have them in back stock but, never bothered cause i was looking for other features for my personal use. i think they were lower end of the crown series and were meant to replace the CE series on a budget. that's one main reason for going the toridial transformer route(torids are cheaper to manufacture than iron cores) and the alternation of the heatsink use and double up of fan use to compensate.

the the CE series naturally was supposed to replace the old macro-tech series but, kinda fell short and other test beds were put out to become testers. the XTI series became the true replacements of the CE series and from my experience worthy of the crown name. that's why i never sold my crown xti 4002 and always kept it. cause it just proved to be very stable no matter what. i was offered flat cash of 800 bucks and lowest 650 before upfront before for it but, never sold it cause people i had come over to test out the gear/subs/speakers i was selling them wanted to give the bigger crown i had a listen and were impressed by how much torque and slam it gave and it sounded really great doing it.

 

Ah well, seems to be moot as the seller never responded to me. There's another guy with a bunch of QSC's right now, a RMX 850, 1450, and MX1500a. Not the best prices I've seen, but half decent for Canada. Pfft, it's not like I *need* more power amps...

 

yea. well you have all your brystons so, you're doing very good and if never felt like they ran out of headroom at all then, you are fine. i needed the large crown as minimum for sub use and couldn't squeeze the extra grand for the 6002 even though the 6002 is the one amp i really wanted in first place but, couldn't quite afford it.

the xti series are pretty much like baby i-techs in a way especially the 6002 but, seems either the 6002 uses a more robust power supply than most i-techs or it's cause the i-techs forced circuss logic dsp affecting it but, 6002 seems to have better 2ohm and bridge/mono 4ohm performance spec wise compared to most i-techs indicating it won't current limit itself quickly under heavy stress or something even though the i-techs are rated for 1ohm loads and xti aren't. i think it's probably marketing reason cause i think the xti 2 series are defiantly safe with all loads just as well even though they warn people don't go below 4ohms for heavy long use. i never had issues running heavy loads on my 4002 for long periods personally so....


the qsc mx series is good if you get the non ''a'' version. the non ''a'' versions are true dual mono design and uses more robust metal die t-03 transistors. the ''a'' version(s) are basically a regular amp with dual secondaries in the transformer but, still claim to be true dual mono. they also use plastic transistors instead so they won't handle the heat as well as the t-03's thermally under heavy loads even though qsc claims it'll run just fine. the ''a'' version is pretty much a cheaper design version during the 90's. the early 80's non ''a'' versions are one to look for and are true work-horses and monsters.

 

The 3B and 4B Brystons are very size/weight unfriendly, so they don't leave home anymore. Although I'm curious to hear their 2.5B, which is the only model in the standard 2U rack size. They turn up so rarely on the used market unfortunately.

I was thinking that with Bryston's new Cubed amps that just came out, that used prices would drop a bit, but if anything it looks like they've gone up. Hmm.

There was actually a non "a" version locally a couple months ago. I was tempted again, but that size/weight thing held me back.

 

yea, i think the mx1500 are something like 52lbs or something. i can imagine carrying a few of them a once being an issue for most people but, even some older folks put up with it since they swear by the sound of them. the old dj i knew who i bought a crown ce2000 off of was like that. he kept all his old amps around even though he as complaining bout how pain they are carrying around but, loved their sound. he just had to sell some off cause his wife was pissed that he was gonna keep all his old dj gear around so he as selling few amps off. i should of kept it since i never got into dj'ing really cause i traded it for some cd decks and then later on found out i never cared to much even though it was fun playing with them so i sold them off to an old head tablist looking to try decks out and digital mixing from a computer.

 

Thinking of getting a Crown XLI 800 to power XTZ 99.25 MKII's (4-8Ohm 87dB) Should be fine right? Reckon the fan will stay reasonably quiet since it's temp controlled? I won't be pushing them too hard because of the neighbours. Main interest in a pro amp is because it's cheap and it is balanced so i can keep my headphone amp/pre amp in it's normal spot and not worry about cable length. How is the noise floor on these?

 

s/n fully wide open(input knobs turned fully clockwise) is 100db so, with those speakers it should be pretty dead silent. i never used the xli amp line-up but, it should provide you with more than enough power since short term peak is 300w which means speakers probably last few seconds or less if amp was cranked at it's full output of 300w rms@4ohms so your speakers are probably most likely 100w on avg handling which is generous guess so the amp should be double the output capability of the speakers meaning you have very good headroom at any given point.

 

Ok thanks! Can't wait to try it out, will post my impression's here

 

I find the s/n of the amps rarely comes into play. It's more their high gains which can potentially bring up noise issues in the earlier parts of your chain. Then again, you probably won't have the gain cranked in a home setting, so nothing to worry about.

 

My only concern now is if the fans will be annoying from my seating position but i have 30 days to try before sending it back so no worries.

I know my speakers pair well with class-d amps, i had their big brother floorstanders hooked up to a Pioneer Sc-2023 and it sounded awesome.

 

Most crowns are pretty balance when it comes to gain. Well, ones I played with. Even wide open they can be pretty darn quiet unless your speakers 100db+/1w cause even on my model 14's which are 97db/1w sound darn quiet with most crown amps I played with. If gain is such big problem though you can simply turn the input attenuators down to half-way point or lower...

It's usually the preamp/mixer that affects the overall s/n ratio from my experience.. it's usually preamp/mixer as weak link of the chain way before source and amp. Just my opinion though.

 

Makes sense, thanks for your input

 

i finally got a chance to listen to some carver amps yesterday. person i met on audiokarma surprisnly came over and wanted to hang out. he is a big carver fan with carver silver seven t's monoblocks i think they're called and had couple other carvers, one being a pro amp which was the carver pm 600. he also brought over the tfm-24 which is not considered pa but, home amp but, has very substantial power for more then avg home use

he wanted to hear what was all the rave with the altecs and wanted to check out my model 14's and brought couple amps to let me check out and of course he was curious how they'll sound on the altecs..

i first tried the carver pm600...i don't know much of this amp except i think it's like 200wpc@8ohms and it uses a class g/h type of rail switching. i powered it up, background was dead quiet with it,even wide open but, sound was pretty good. sounded clear but, had a kinda of like roughness to it. like it was clean but, not as clean you expect the signal to be but, then again it was on a signal ended rca with 1/4'' adapters i tried it with cause i didn't have long enough xlrs to go from preamp to power amp...might give it a try again next time around and ask if i can try it as loaner for week or so.... or maybe it was cause it was a rail switcher maybe cause i never had experience with class g amps before personally so don't know....i only had experience with class d crowns and traditional linear a-a/b amps.... even qsc's i ever tried in past which were pretty decent were class a/b.. never used the newer class h models....but, anyhoo, the crown xls 2502 over thrown the carver pm600 in pure clarity and transparency surprisingly...


then i hooked up the tfm-24 which is same as the tfm-25... it looks like a piece of crap to be honest with it's horrible simple like cheap plastic faceplate but, actually performed lot better than the pm600 i thought.. it was cleaner sounding all around which was surprising cause i just assumed by looks and specs the pm600 would of been the better performer... i actually liked how it made the altec 14's sound. this is probably one carver i wouldn't really mind having really as a back up and would probably have it over the nad 2700 i have sitting around as a backup... i never though compared it directly to my crown since it was getting very late at the time so,next time i will probably....

he runs carver amazing platinums which are line array ribbons with i believe line array 12'' woofers which are basically pro woofers. i heard great things bout them and people liking them a lot more than esl's,quads and magnepans but, never personally heard them. but, told him when i have time i'll come over his place defiantly to give them a listen to see how they do. will even bring my amps over there to see how he likes real power behind the speakers sound too. my crown xti 4002 alone has good bit more output into dual/stereo compared to his monoblocks.. told him though i love my crown xti 4002 and not for sale. don't care if i got offered full retail value for it. it proved to be one hell of an amp that sounds amazing and when it comes time for abuse it takes it no problem....but, i had fun..