# Xetec Gravity 8G-1000 amplifier



## FoxPro5 (Feb 14, 2006)

The Xetec 8G is a very unique 8 channel amplifier. The engineers somehow figured out how to get 8 channels into a 11x11" heatsink. The trick, it seems, was to use different circut boards to connect the channels internally for various modes of operation. Xetec calls them Modules, and you get a total of 6 of them with the amplifier: two 4 channel, two 2 channel, and two 1 channel modules. Here's what they look like:









With the three different modules you can configure the amp in the following ways (rated power at 13.8v into 4 ohm;2 ohm):
8 ch: 8x83; 8x130 
6 ch: 4x83 + 260x2 
5 ch: 4x83 + 330x1; 520x1 
4 ch: 4x260
3 ch: 2x260 + 330x1; 520x1
2 ch: 330x2; 520x2

*Build qualtiy:*
The whole amp is build strong and tough...right down to the modules. 
My trusty bathroom scale showed 14lbs. The heatsink is dense and thick . You could back over it with your car and it would just laugh at you! 

*Installation:*
On one side of the amp you have all the speaker connections and the RCA inputs. The opposite side has to power connections as well as two capacitor ports, one for channels 1-4 and one for channels 5-8. 

What bothered me the most about the layout is that instead of labeling the speaker terminals + and - they labeled them CH1 and GRD. It just makes it arduous to read rather than just match + and - up. 

Also, the max power and ground wire it will accept is somewhere between 8 and 4 gauge. I did use 4, but had to thin it down to get a nice snug fit.

*Configuration:*
The easiest part about the install is working with the modules and the gains. Here you can see the amp with the top plate as it normaly is:









Remove the top plate and you have access to 8 independant gain controls for each channel:









Remove the scale plate and you see the guts of the amp and the two configuration modules. The top module runs channels 1-4 and the bottom runs channels 5-8: 









*Performance:*
I've run the amp 2 different ways so far:

1) 6 channel mode: 83x4 to the midrange and tweeters + 260x2 to the midbass. Great power off the fronts to the mids and tweets. I don't know if I didn't connect something correctly, but there is no way I was getting 260 watts to each midbass! There wasn't any more output it seemed than if I ran 83 to each. I just tried this briefly so I will have to double check my connections again. It can be a little tricky connecting the speaker on the right terminals with the RCA's on the right inputs when you bridge the amp.

2) 5 channel mode: The sub channel seems to do rated power. I have to set the gain to about 1/4 to get the needed power out of my sub, however. 

*Sound quality:*
So how about the sound quality anyway?? Well, everything that's supposed to be in the music is there as far as I can tell. 

*Technical specifications:*
Peak output power: > 1500 watts total
Max input current (@ 13.8v): 100A
Idle current (no signal): 1.2A
THD: <.05%
SNR: >89dB(A)
Freq response: 7 Hz-50 kHz
Input sensitivity: 250mV - 6V
Weight: 14 lbs
Aluminum-Magnesium diecast heatsink (11x11x2.5")
Gold plated terminals
MSRP: $1300

*Conclusion:*
Since this amp is so versitile and easy to work with I think it's an excellent buy. You have a lot of power on tap to run anything you can throw at it. The form factor is unmatched. To run a passive comp set at 260 watts per side with 520 out back to the sub from a single amp that takes up less than a square foot??? I really don't think you can find this anywhere else to tell you the truth. If they only made it 7 channel capable it would be the only amp in my car and I'm sure many others running 7 channels actively as well.

Unfortunately it seems that Xetec is now out of commission.  Their website is down and even the US distributor, ProTech Loudspeakers can't get ahold of them. Maybe they'll be back?? To my knowledge Xetec is a house brand of the amplifier manufacturer Chunglam. Maybe they will continue to make the 8G? Lets hope so.
*
*Follow up note**
One thing I forgot to mention about this amp is that there are no onboard controls. No crossovers, SSF, remote bass, pass-through or line out...just gain, that's it. Kind of nice if you don't need any of that stuff.


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## andthelam (Aug 9, 2006)

great review! Im always in the market for a high power multi channel amplifier. I like the idea of running a single amp. Too bad they may be defunct. If you dont mind me asking, how much was the amp?


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## FoxPro5 (Feb 14, 2006)

Thanks!

To give you an idea of the current market price: http://cgi.ebay.com/ws/eBayISAPI.dl...MEWA:IT&viewitem=&item=260074398610&rd=1&rd=1


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## alphakenny1 (Dec 21, 2005)

he stole this amp from me   . 

Great Review man!


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## bassfromspace (Jun 28, 2016)

What are the external measurements on these as they look very small? Also, under the 6 channel watt rating theres only 5 channels accounted for. Is the 260 for 2 channels?

Thanks for your help

I may have found my single amplifier solution.

Edit: I see your measurements.


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## alphakenny1 (Dec 21, 2005)

well the problem with these amps is that the xetec line is VERY hard to get the U.S. you might have trouble finding one to be honest.


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## bassfromspace (Jun 28, 2016)

alphakenny1 said:


> well the problem with these amps is that the xetec line is VERY hard to get the U.S. you might have trouble finding one to be honest.


Yeah, I know. That makes me want to cry as the 8 channel would be perfect in the back of my crx. The PDX amps are another option, but they're way more expensive then the Gravity amps. Who knows?


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## zfactor (Oct 19, 2005)

yeah i wanted the 8 channel myself also.. damn it


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## bassfromspace (Jun 28, 2016)

zfactor said:


> yeah i wanted the 8 channel myself also.. damn it


Let's cry together.


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## FoxPro5 (Feb 14, 2006)

It's your loss guys. I posted a link to the one on ebay in the For Sale section that Protech was selling. It was a NR auction and it got 3 whole bids.  

Contact Rich Duda at Protech, he might be able to get you one. [email protected]

But I doubt it, because in my recent email conversations with him he said his inventory was pretty dry. Tunershop is the other US Distributor and it seems they dumped the rest of their inventory over on ECA recently. 

Otherwise I could sell mine........














....errr maybe not.


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## chad (Jun 30, 2005)

What class of amplification is it? It seems pretty darn small for ClassAB! But appears to be in this pic.

http://ampguts.realmofexcursion.com/Xetec_Gravity_8G-1000/inside2.jpg

Zfactor it says that's your pic! 

Chad


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## FoxPro5 (Feb 14, 2006)

chad said:


> What class of amplification is it? It seems pretty darn small for ClassAB! But appears to be in this pic.
> 
> http://ampguts.realmofexcursion.com/Xetec_Gravity_8G-1000/inside2.jpg
> 
> ...


What the hell! I was JUST about to post that!!!  You're good Chad....damn good.  

AFAIK it's Class A/B.


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## zfactor (Oct 19, 2005)

i had one here but i never got to use the 8 channel .. i couldnt find the rest of them i needed to complete the setup so i sold it.. now i regret it i really and wish i could find more of them, yes its a a/b amp as far as i know. i actually really liked its look and it was def built well but as said before in this thread, my buddy that bought it said it seemed weak for what it was supposed to be. id love to get one and bench it..


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## FoxPro5 (Feb 14, 2006)

Do you mean weak as in it didn't deliver according to its specs (13.8v)?? 

I have a technical question about something Xetec claims in their manual. Werewolf, you there?? They claim that the amp has "balanced RCA inputs for maximum noise supression." How can this be if there's only a single set of RCA inputs??


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## zfactor (Oct 19, 2005)

he said it just didnt have the oommphh he was expecting. he also noted the same as you did when bridging it he said it def seemed like ti was wired wrong or not really being bridged but he checked and double checked and he was wiring it right.. so cant say number wise but he didnt think it performed as well as he expected. he did say it sounded great..


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## bertje (Feb 10, 2007)

Hello, I was selling/distributing Xetec in Holland for a few years. (www.12vhifi.nl). The 8G1000 is a class AB amplifier, based on the Gravity 4G600. There are few left in Germany I think, I never sold them.
Greetings,
Rob. 
12v HiFi


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## Guy (Feb 16, 2006)

Very nicely done review. Now I don't have to read the instruction manual!  
I was wondering about the balanced input issue as well- some of the Xtants back when also advertised balanced input capability, and they also had the "normal" number of RCA inputs.


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## zfactor (Oct 19, 2005)

damn where are you guys finding these....??? i should not have sold the ones i had


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## FoxPro5 (Feb 14, 2006)

Did you find one G Rahn?? 

The instruction manual is pretty weak.


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## Guy (Feb 16, 2006)

B-Squad said:


> Did you find one G Rahn??
> 
> The instruction manual is pretty weak.


go-G Rahn-go


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## CaseyWalsh (Jul 25, 2005)

B-Squad said:


> ...They claim that the amp has "balanced RCA inputs for maximum noise supression." How can this be if there's only a single set of RCA inputs??


RCA jacks can be used for balanced inputs as long as the outer sleeve isn't grounded and a proper input circuit topology is used. You can use a DMM to test for balanced inputs by measuring the impedance from the center hole to ground and then the outer sleeve to ground. If they are both above 1000 ohms (probably 10 or 20 k-ohms) then you have a balanced input. For single-ended inputs, the sleeve is usually a very low impedance to ground.

One caveat: Some poorly implemented balanced inputs place a DC-blocking capacitor _before _ the terminating resistor, in which case a DMM won't work for the test.

Cheers,
Casey Walsh


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## FoxPro5 (Feb 14, 2006)

Brilliant! Thanks for the info.


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## aranthop (Dec 30, 2007)

Hi Guys,

would you know how much is the going/selling price for this? I'm very interested in getting one. thanks.


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## Infinity (Jun 28, 2005)

aranthop said:


> Hi Guys,
> 
> would you know how much is the going/selling price for this? I'm very interested in getting one. thanks.



Good luck with that. They don't make them any more.


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## FoxPro5 (Feb 14, 2006)

Put it this way, I've had "Xetec" on my ebay auto search for at least a year and have only seen one item which was a four channel that I believe a member here ended up getting. 

The company is cuputz and ProTech dumped their inventory long ago. There was an 8G on ebay at one time for $500 and it sold right away. 

BTW, amp still works great!


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## aranthop (Dec 30, 2007)

Thanks foxpro5. Do you have one of this babies?


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## GlasSman (Nov 14, 2006)

FoxPro5 said:


> Put it this way, I've had "Xetec" on my ebay auto search for at least a year and have only seen one item which was a four channel that I believe a member here ended up getting.
> 
> The company is cuputz and ProTech dumped their inventory long ago. There was an 8G on ebay at one time for $500 and it sold right away.
> 
> BTW, amp still works great!


I think G RAhn got that Xetec off Ebay a few months ago. I know he has one.


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## SQ_Bronco (Jul 31, 2005)

FoxPro5 said:


> Put it this way, I've had "Xetec" on my ebay auto search for at least a year and have only seen one item which was a four channel that I believe a member here ended up getting.


x2. 8g's pop up from time to time on "Ebay Germany" and don't show up in global searches for whatever reason, but you'll have to convince the seller to ship them and they usually won't (or quote $150). There's a 4G there now but it's $350+.


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## Infinity (Jun 28, 2005)

WHat I don't understand, is weren't these Chunglams "house" brand? If that's the case, why haven't we seen them pop up as Memphis or Crossfire models...or is that essentially what the Memphis S-class are?


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## FoxPro5 (Feb 14, 2006)

Infinity said:


> WHat I don't understand, is weren't these Chunglams "house" brand? If that's the case, why haven't we seen them pop up as Memphis or Crossfire models...or is that essentially what the Memphis S-class are?


Sounds like it was their "branch company" whatever that means:
http://www.chunglam.com/eng/board/read.php?boardname=enotice&id=3

Looks like their house name was/is Caliber and has been so since '95. Crossfire came along in 2000.


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## GlasSman (Nov 14, 2006)

I'm pretty sure I read Xetec was their house brand for the German market. It was on this website.


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## GlasSman (Nov 14, 2006)

Here:

http://www.diymobileaudio.com/forum/showthread.php?t=7585&highlight=chunglam


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## aranthop (Dec 30, 2007)

To those who have used the amp, how is it?


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## FoxPro5 (Feb 14, 2006)

aranthop said:


> To those who have used the amp, how is it?


You are not going to find a lot of feedback, man. Thus the purpose of this *review*!!!! 

GlassMan, is there and echo in here?


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## bm300 (Jan 3, 2008)

I believe I was the lucky person to buy the last one available on ebay, and I have to say it’s really a nice amp. Clean, bright and dynamic. Very compact for its power and sound quality and VERY heavy for its size! My experience is similar to others posts in that bridging doesn’t seem to produce the amount of power I expected, but I was not at all disappointed with the quality. It actively drove a pair of Morel Renaissance Series 2-ways and a pair of Boston LF Series subs flawlessly.

I especially like the layout of this amp. The location of the terminals in relation to the heatsink and controls make a perfect design for mounting vertically against the back seat and still enable easy adjustments. It’s also nice that there is a level control for each of the eight channels. Its only pitfall for my purposes was I could not configure it for 7 channels. During my multiple install phases, I wanted to try an active 3-way system and bridge the last two channels to a single sub. There was no way to do this with the included modules or according to the manual. This was not a tragedy, just an inconvenience.


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## FoxPro5 (Feb 14, 2006)

bm300 said:


> I believe I was the lucky person to buy the last one available on ebay, and I have to say it’s really a nice amp. Clean, bright and dynamic. Very compact for its power and sound quality and VERY heavy for its size! My experience is similar to others posts in that bridging doesn’t seem to produce the amount of power I expected, but I was not at all disappointed with the quality. It actively drove a pair of Morel Renaissance Series 2-ways and a pair of Boston LF Series subs flawlessly.
> 
> I especially like the layout of this amp. The location of the terminals in relation to the heatsink and controls make a perfect design for mounting vertically against the back seat and still enable easy adjustments. It’s also nice that there is a level control for each of the eight channels. Its only pitfall for my purposes was I could not configure it for 7 channels. During my multiple install phases, I wanted to try an active 3-way system and bridge the last two channels to a single sub. There was no way to do this with the included modules or according to the manual. This was not a tragedy, just an inconvenience.


Very cool. Did you buy it new from Protech?

So the consensus here is that it's not a ballsy amp. I totally agree. When compared to other similarly rated amps (ex DLS A2/A5 that does 85w at 13.8v) it's "weaker." Not complaining, just saying. Yes, I realize one would need to match voltage output. 

The gain pentameters are great on this amp. With some, you can barley turn the knob and you get a 3v jump. With the Xetec, you get a nice smooth, analog (imagine that) response that you can dial in to .1 - .2v.

With every sub I've used with the amp (all 4 ohm) I've had to turn the gains up to about 1/3-1/2 in order to get a decent amount of output. 

Currently, I have it bridged down to 330x2 at 4 and am running 8 ohm midbasses. In this case, the gain is all the way down. No, this is not a waste of the amp by any means. Unless you think 660 watts in an 11x11" acreage is a "waste." 

Also a good point; this amp will not run 7 active channels. If you do come across one, don't buy it thinking it will.


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## bm300 (Jan 3, 2008)

Yes I did buy it from Protech. Nice Guy!

I like what you've done with it. I actually boxed mine temporarily because my processor, which was also my crossover, developed arbitrary intermodulation noises. It drove me nuts, so I removed the processor and put back my JL 500/5 amp because it has an internal crossover. Common sense almost won out because I took pictures with the intentions to post the Xetec on ebay, but I can't bring myself to sell it.


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## FoxPro5 (Feb 14, 2006)

bm300 said:


> Common sense almost won out because I took pictures with the intentions to post the Xetec on ebay, but I can't bring myself to sell it.


It seems it did! I know the feeling. Just can't live with the regret.

I had it open recently to find the fuses on the board, but didn't see any. Anyone see a fuse?










The amp comes with a very nice, gold plated 100amp fuse to be used with it, but I've never used it. Maybe I should?


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## bm300 (Jan 3, 2008)

FoxPro5 said:


> I had it open recently to find the fuses on the board, but didn't see any. Anyone see a fuse?
> The amp comes with a very nice, gold plated 100amp fuse to be used with it, but I've never used it. Maybe I should?


I don't see one. It seems they didn't waste any real estate on the non-essentials. I have a 100amp breaker on my system, so I didn't use my fuse either. I assume you're using some sort of protection, no?


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## Sinfoni_USA (Mar 9, 2005)

Yes... Please use the fuse block that came with the amplifier. It has no on-board fusing...

Man that was a great amplifier... wish I had kept it... 

J


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## FoxPro5 (Feb 14, 2006)

You really think I need to protect a 12" 4 AWG power wire between the distro block and the amp? I have the primary fuse about 8" from the battery (1/0 that carries all the power to the back of the car for the amps.)

In the troubleshooting section of the manual, it does say to check the on-board fuse as one of the measures. You sure it's not on the other side, maybe?


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## bm300 (Jan 3, 2008)

Sounds like you're good. Everything I've read recommends fusing near the battery and at the distribution block. The 12" lead is average. You obviously know what you're doing, probably more so than me. I didn't see any mention of you having problems so I'm confused why you're reading the troubleshooting section.


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## FoxPro5 (Feb 14, 2006)

bm300 said:


> Sounds like you're good. Everything I've read recommends fusing near the battery and at the distribution block. The 12" lead is average. You obviously know what you're doing, probably more so than me. I didn't see any mention of you having problems so I'm confused why you're reading the troubleshooting section.


I probably should add the fuse b/c the d-block isn't fused. The fuse at the battery really is there to protect the wire, not the amps. 

<--- kinda dumb and lazy sometimes. :blush: 

I lost my RTL for the amp due to a bad relay or the cold or some BS. Initially, I thought it was the amp itself so I took it apart to investigate. Odd that there is not one fuse on the board, though. I should probably sell the POS....  





















Nah....


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## Sinfoni_USA (Mar 9, 2005)

I did a little more research... the 8G1000 does not have an internal fuse or breaker... It is straight wire with gain... Gotta love it !

Now go put that 100A fuse on it... 

J


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## FoxPro5 (Feb 14, 2006)

Tn_Audiophile said:


> I did a little more research... the 8G1000 does not have an internal fuse or breaker... It is straight wire with gain... Gotta love it !
> 
> Now go put that 100A fuse on it...
> 
> J


Thanks Jeremy. Will do, boss!


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