My "new" AMC 2100 blew up lastnight after 30 minutes! HELP!!

[BHTX]

First of all, I'm one of those that seem to have the most horrible luck with every little thing I do. It never ends. After the purchase of a used Golden Theater GTX-1 pre/proc and matching GTX-A 5 channel amplifier from Audiogon became a disaster, I decided to go a different route. This is after I purchased a pair of Eminent Technology LFT-8A's from Audiogon as well, which the left tweeter is currently in the hands of Bruce Thigpen as we speak...due to it malfunctioning with a bad resistance and low output.

So anyhow, I decided to go a different route..."stacked" LFT-8A's in a hi-fi/HT setup...all while attempting to get the absolute very most for my money. You can read the stacked LFT-8 review here: http://www.eminent-tech.com/stacked8review.html

My plans are/were to run a pair of Eminent Technology LFT-8A's for each channel, possibly including a pair for the center channel behind an acoustically transparent screen, and 2 pairs of Magnepan MMG-W's for the four rear channels. Each LFT-8A would be powered by an AMC 2100 in bridge mode (250 watts at 8 ohms). Each pair of MMG-W's would be powered by an AMC 2100 in stereo mode (100 watts per channel at 8 ohms). This would eventually end up being 3 pairs of LFT-8A's, two pairs of MMG-W's, and 8 AMC 2100 amplifiers (6 bridged mono, and 2 running stereo)...

I currently have an Outlaw 990 on its way to me. Also recently purchased a couple of Buttkickers and Buttkicker amplifiers...one which will hopefully power two Ascendant Audio 15" Avalanche woofers in custom 300 liter Sonotube enclosures, a pair of used Magnepan MMG-W's for rear channels, and a ton of other stuff...Audiocontrol Bijou THX EQ, Carver C-9 Sonic Hologram Generator (just for fun), etc etc...

One of the few amplifiers I was able to find that had line outputs to daisychain or connect to other amplifiers to power 2 or 3 pairs of Eminent LFT-8A's, also seemed to be a great bargain...one of the biggest bang-for-your-buck amplifiers out there. However, I might be wrong. Very wrong. It was either the AMC 2100, or Audiosource Amp One/A. I went with the AMC 2100. I currently have one used one that just blew up on me lastnight after about half an hour of use...along with one brand new one, unopened in it's box...and another used one one its way.

So, getting on with it... I finally decided lastnight to hook up the first AMC 2100 I had bought, which had been sitting around since I received it, as I've been too busy to fiddle around lately. I won the auction on the 10th of this month (December), and received it within a week...

Here's the auction: http://cgi.ebay.com/ws/eBayISAPI.dll...8346&rd=1&rd=1

Since the tweeter in my left LFT-8A is being repaired by Bruce, I was forced to connect the amplifier to only the right channel, which is how this system was going to be setup anyway (1 AMC 2100 amplifier bridged to each LFT-8A).

Lastnight, after the devastation, I sent the following email to the seller on eBay that I received the amplifier from...

"Hello,

I finally got around to hooking up the AMC 2100 tonight. I WAS planning on getting several of these to run an entire HT setup. Anyway, about an hour ago, I connected this amplifier in bridge mode to one of my Eminent Technology LFT-8A speakers. I sat back and played several tracks from a few CD's. After about 30 minutes, I found myself toe-tapping along at moderate volume to a Donald Fagen track (Steely Dan), called Trans-Island Skyway...the first track from his great album, Kamakiriad. I was about half way through the middle of the track when suddenly...OMG...SPARKS AND A HUGE CLOUD OF SMOKE PUFFED UP FROM THIS AMPLIFIER!!!. I don't know what to do! My living room STINKS like FRIED AMPLIFIER! I don't feel as though I've done ANYTHING wrong whatsoever for this to occur. I'm very curious as to whether or not this amplifier was repaired in the past. Has it? PLEASE HELP!! Once again, I was planning on purchasing 8 of these to run a large home theater! Please reply!..

Brandin"

I obviously haven't heard a reply as of yet.

If you look at the auction page, the first thing you'll obviously notice is:

10 DAYS MONEY BACK GUARANTEED

...However, it's obviously been over 10 days since completion of the auction. But...I JUST connected the amplifier and turned it on for the first time LASTNIGHT!

So anyway, after all of that, I proceeded to inspect the amplifier the best I could. The screws don't appear to have any scratches or paint missing on them, and it doesn't look like it's ever been taken apart. After I was finally able to find my flashlight, I can't seem to find ANYTHING out of the ordinary. The smoke and sparks came from near the center of the amplifier, and maybe a little to the left side. Upon observing this area with a flashlight, there's nothing there except some wires soldered to a board. All of the capacitors appear to be fine. None of the fuses seem to be blown. I refuse to disassemble the amplifier as of yet, since the last time I did that with a piece of equipment in a similar situation...I ended up wishing I hadn't. But yeah...from looking at things from the top with a flashlight, everything looks fine...can't see anything wrong. There IS however, one spot on a board on one side of one of the large heatsinks that I can't tell what component it is, but it looks like something has oozed from it...but on the other hand, it looks like it's probably just glue. I've stared and stared at it, and can't figure out what it is.

The amp is definitely NOT working. After it "blew up" in front of me, I jumped up off the couch and ran across this room to unplug it. The green power light was still on...just no tunes, and some initial sparks and pops, along with lots of smoke. So, I guess the amp isn't completely dead. I haven't tested one channel of the amp (once again, it was bridged), but I don't really want to, either. With so many things blowing up on me in the past (my luck at its best!), I've done that before...only to worsen the situation. When the amp went nuts, there wasn't any buzzing or anything. From what I remember, the music just suddenly stopped.

Does anyone have any advice on what I should do? I know it's Christmas, and I'll probably have to wait a bit. But I'm curious as to what component was actually the culprit, since I can't seem to find anything. I know it's difficult to say anything without even a photo to look at. I guess I just thought perhaps some of you guru's could at least provide some suggestions of what to look for, or at least some advice on what I should do.

Thanks in advance,
Brandin

[analog_sa]

The smoke and sparks came from near the center of the amplifier, and maybe a little to the left side.

Hmm. It may be the heart.

Sorry to hear about your ordeals but from your descriptions one wouldn't think that you can't repair it. Best refer it to qualified personnel.

[anatech]

Hi Brandin,
I repaired a lot of those under warranty.

Do not bridge them, they can not take the load. It's not an expensive amp to begin with, so don't push those! You may have been okay if you had run the amp in stereo mode. Or maybe not.

Sorry, that's the truth about them. What you should be running are some Adcom amplifiers. Good sounding, they are robust and not terribly expensive. The older GFA-535 / 545 / 555 and up are good to. Do not run those bridged either. You'd be further ahead to simply buy the larger stereo units. The 565 is a mono, non-bridged design. Carver would have been another good choice, Sunfire for new product.

-Chris

[BHTX]

I just received the seller's response...

"Hi,

I am so sorry to hear that...wrong connection to caused the problem. This machine like new and never been in repaired.
Thank you OJ"

Pretty $hitty, eh? I'm screwed. I guess I'll have to get it fixed, then I'll have 3 more amps to get rid of...along with a several thousand dollars in other stuff that I STILL have to sell. *sighs*

I guess I'll be looking at other amps now.

[BHTX]

I knew the amps were "cheap", but I figured they'd be a great deal... offering a good amount of power to each LFT-8A. Once the setup was complete, I obviously wouldn't have been running the amplifiers full-range, but would have used the xover in the Outlaw 990, of course. However, the simple fact that it not only can't perform ANYWHERE NEAR it's rated specifications, but BLOWS UP when slightly pushed anywhere above moderate listening levels...just doesn't appeal to me. You know...I probably could have purchased all 8 amps at once, ran them with a 60 or 80Hz highpass xover, and NEVER had any problems. BUT, screw that. If it's going to heat up THAT fast and perform so $hitty, I don't want anything to do with them. They seemed ok from the few user reviews I could find, other than a couple of people with negative comments toward the amp being a little "forward" and too bright. I figured hell...if anything, it might help the LFT-8A's out with their slightly rolled off highs. With only 1 speaker hooked up, it was obviously a bit difficult to get a good impression. However, the tonal qualities of this amplifier are DEFINITELY forward and bright. I couldn't imagine listening to it on a regular cone-type loudspeaker system.

But regardless of what it sounded like...it blew up when it shouldn't have. Yes, the LFT8's are incredibly "inefficient", at 83 dB/watt. But still, this just shouldn't have happened.

As far as the Adcoms go, I'll have to take a closer look when I get home later tonight. But thanks for the recommendations...

Can anyone else give any recommendations of amplifiers? It would be really convenient for the amplifier to have a line level output to hook up 2 amplifiers per channel, since that's what I'll be doing in the end. Otherwise, I'll have to use a Y cable...which I don't really like doing.

[BHTX]

Oh yeah, as far as amplifier recommendations go... a bare MINIMUM of 200w/ch. Preferrably 250-300+ or so. I'm tellin' ya...these speakers eat up power like there's no tomorrow. One of the channels in my Golden Theater GTX-A 5 channel amp has never worked since I received it used on Audiogon. So, I ran 4 of the outputs to the pair of LFT-8A's...one to each woofer, and one to each mid/tweeter panel. That amplifier is rated at 200w/ch @ 8 ohms and 400w/ch @ 4 ohms. I later found out the hard way how unstable a lot of the Golden Theater/Golden Tube/Solo Electronics products were. Regardless, it seemed like a really well-built amplifier...and the top of the case NEVER seemed to get too much above room temp. I believe it's one of those designs where each channel is a seperate mono amp. Anyway, along with the matching GTX-1 preamp/processor...it sounded REALLY clean on 2 channel audio. So yeah, 400w/ch isn't too much!..lol. I loved the way it sounded, but with the processor being a bit outdated and buggy, along with the matching amp's channel not working...and then me having so many thoughts of buying another set of LFT-8A's...I just decided to go another route. I love the way these speakers sound...they're great at what they do...but they suck all the life out of just about any amp I give them. Oh well. Back to searching for amps, once again. And again, and again...

Price/performance is the biggest concern.

[anatech]

Hi Brandin,
You are asking a lot of an amplifier, so stop looking at inexpensive stuff.

Go ahead and use "Y" cords, that will broaden your amplifier choices. Most pro amps will not sound good to you given your comments. Therefore, buy good home amps. Do not bridge them. Leave lot's of clear air space for ventillation.

My recommendations remain unchanged.

-Chris

[Richard Ellis]

Sorry to hear about your meltdown of your prized equipment
I have had a Carver TFM-15CB (100 WPC) for three years now with no problems whatsoever & trust me she has not been pampered! Our DIY towers are running at about three and a half ohms. Yes she does have drawbacks (No peak indicator..I use the wattmeter light flicker as an indicator)! The larger TFM Carver series just might be a good deal...they are cheap & abundant on Ebay. You really don't want to know what I paid for mine as it was at a garage sale & they had no idea what it was....I kicked my wife stealthely when I saw the 'asking' price & $55 later we walked away with a HK tuner, Yamaha pre-amp, & the Carver.
______________________________________Rick........ .

[BHTX]

Originally posted by anatech
Go ahead and use "Y" cords, that will broaden your amplifier choices.

..Boy you're not lying about that! That little output feature is REALLY difficult to come by. Other than the AMC and Audiosource CRAP (and I repeat...CRAP!)...there doesn't seem to be very many at all. Many of the large multizone amplifiers offer a single line output, but those amps just won't cut it. I've looked at ALL of them.

Speaking of which, after thinking about it...I've never really known the disadvantage, if any, of using a Y adapter cable. I've just always assumed it was a good thing to avoid. What does it do to the preamp's output? Would it be like wiring it in paralell? Or would it lower the overall output, therefore giving less output to the amplifier's inputs...requiring an increase on the volume knob to achieve the same volume levels from each speaker? I obviously don't know a whole lot when it comes to these things (that's why I read this forum sometimes).

Also, what is it that the few amplifiers that offer a line output are actually doing to provide it? Would it really be any different than using a Y cable?...besides convenience, of course.

...I'm really curious about this, as I've never really known for sure.

Originally posted by anatech
The larger TFM Carver series just might be a good deal...they are cheap & abundant on Ebay.

Your recommendations are greatly appreciated, as every bit helps. For the last several hours, I've been checking out the older Adcom amplifiers, specifically the GFA-555 and whatnot...along with a few other amps...

For the last couple of hours or so though, the idea has been running through my head of just going ahead and selling a bunch of stuff...saving up a bit more dough, and then throwing out the cash for a brand new Outlaw 7500, which I just realized is basically identical to the ATI 2007. From what I understand, many of Outlaw's amps are based on ATI's offerings...but for a fraction of the price, of course.

The plan would be to eventually end up investing in two of these amplifiers (10 channels of output @ 200w each). That'd be quite expensive though. However, I'd definitely have to take my time and build on the system for a while, which I really wouldn't mind...except that more often than not, I usually end up never doing what I had initially planned if it doesn't all get done at once, lol. I'll always end up with another idea, changing plans and doing something else...or deciding I no longer want it for some other reason. I'd just need to force myself to stop browsing around, and stick with the plan.

Oh yeah, and it looks like Outlaw is selling a nifty little overpriced Y cable. No actually, it's not that expensive at all...just $24.95. Looks pretty nice, too. Boy, Outlaw sure is convenient and thoughtful, aren't they? Great selling strategy, I guess. When I first heard of them, I wasn't a fan. A few years later, after reading up on a few of their more current products, they don't seem so bad afterall. Seems like quite a deal, really. ..Which led me to the recent purchase of my 990, which is still on it's way. Hopefully that'll work out OK. I'm keeping my fingers crossed. Or not? Am I completely WRONG about this assumption as well? I sure as hell hope not! But hey...the last time I thought I found a great deal, that turned out to be a DISASTER! Same goes with the "deal" I found before that...and before that...etc etc.

Anyway, any thoughts/comments/opinions on the 2x Outlaw 7500 / Model 990 / 3 pairs of LFT-8A's / 2 pairs of MMG-W's setup? Of course, I'm still considering the option of running 4 or 5 good stereo amps as well...such as the Adcoms. The Outlaw 7500's, at $1599 each (and not available used, or very rarely) would cost significantly more, but might seem better in the long run. *shrug*

*sighs* One of these years, this system WILL be "complete".

[BHTX]

Still considering the Adcom GFA-555's. The only thing that keeps me from going for it is the fact that they're so old, and it seems as though people are repairing and upgrading these things left and right. Buying a few used GFA-555's, it seems like I'd never really know what I'm actually getting until I get it at my door, get the screw driver, open up the case, and then take pics and post a thread on here to find out whether or not everything with the amp appears to be "stock" or "okay".

The Outlaw 7500's, on the other hand, I feel like they're pretty far from the most for your money, but would probably still do the job, nonetheless. What do you guys think?...

Naked Outlaw 7500 #1
Naked Outlaw 7500 #2
Naked Outlaw 7500 #3
Naked Outlaw 7500 #4