GTD amps

Is this amp OK?
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Rick Lee
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Re: GTD amps

#16 Post by Rick Lee »

Well, I bought one to use in the shop and as a backup for demos. http://www.ebay.com/itm/2-Channel-4500- ... 6102784%26

Seems ok. On music it seems to bump the clip light at about ~20 - 25 volts into ~10 ohm T45. Definitely more output than my Bash 300. Bridged it will go ~35-40 volts with the clip light bumping on. The inside has a big transformer on one side and the amp "tunnel" on the other. Too lazy to take a picture for you amp heads out there. Since it claims "ATR technology" I'm assuming it's class H?

I bought it when it was $139, now it's gone up to $149. One year warranty supposedly... Course if they run out of stock for a year not too sure how good that warranty is...

This one was $179 the other day but it's $189 now... http://www.ebay.com/itm/2-Channel-6500- ... 5983586%26

I'd say if you're not finding anything on Craigslist this might work for the garage bands out there.
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Ryan A
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Re: GTD amps

#17 Post by Ryan A »

Rick Lee wrote:
Seems ok. On music it seems to bump the clip light at about ~20 - 25 volts into ~10 ohm T45.
That's a whopping 62.5 watts.....for 28 lbs? Not my cup of tea.

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Rick Lee
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Re: GTD amps

#18 Post by Rick Lee »

I'll admit I don't know much about amps. All I've done is hook my voltmeter in line with the output from one channel of the amp while playing a cd with normal amounts of bass. With the same setting the Bash 300 was maxing out at 9 or 10 volts while the GTD was 20~25. The GTD was pushing 30~35 volts with the clip light flashing. I kept the volume there for about 5 minutes and the GTD didn't seem to run out of steam. Fan was running full speed; exhaust air was slightly warm. Bridged the GTD hit 60 volts once but I backed it off because I certainly don't want to blow a nice driver. Obviously I couldn't hear any distortion. No matter how much I pushed the volume the Bash wouldn't go past about 10~12 volts. Holding an spl meter 3 feet in front of the sub (inside the shop) the GTD was hitting 115~120db; the Bash about 110db. Xover was the LFE out from the receiver.

I know none of this is accurate measuring - I don't have a computer in the shop and right now I'm too swamped to drag stuff around to do more accurate testing. Is the sub exactly 10 ohms? Don't know. Is the voltage reading accurate? No. Just me standing there looking at what seems to be an average from a music source. Is the spl accurate? No. I'm in a room holding a C weighted meter reading low frequencies. Do I know how much headroom is left when the clip light flashes? No. If I had to guess what the output of the amp is I would say 150~200 watts per channel.
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koturban
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Re: GTD amps

#19 Post by koturban »

Rick Lee wrote:Hmmm... looks like they're back with different models. The ones I have in a local church install are still doing ok after a year... not that they push them hard.
http://www.ebay.com/itm/2-Channel-6500- ... 5983586%26

36lbs and ATR?
How do you get 6500 watts with a 10 amp fuse?

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Re: GTD amps

#20 Post by byacey »

They use the same "proprietary" mathematical formula to calculate the fuse rating as what they use to spec the audio power output.
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Re: GTD amps

#21 Post by 40 Hz »

I bought one of the GTD Audio T-4500's for my kids when the price was $139. Hey, it looks like a QSC if you squint your eyes real tight!

As far as voltage goes, they put out 53 volts AC (350w @ 8 ohms / 700w @ 4 ohms / 1400w @ 2 ohms) per channel when maxed out.

The PEAK light comes on at 40 volts AC (200w @ 8 ohms / 400w @ 4 ohms / 800w @ 2 ohms), but the PROTECT lights never lights up. I don't hear it starting to distort when the PEAK lights comes on, but it is very loud at that point inside the house, and for what I am using it for it never needs to be that loud.

I own (or have owned) a lot of power amps, everything from more expensive Hafler, Crown, QSC and Crest amps to the more budget oriented amps like Behringer and Peavy. This is the first more consumer orientated power amp I have ever bought, but for the price I paid, I am pretty impressed.

It's frequency response seems flat, and it sure gets loud for the price it cost. It is a substantial step up from most home audio / car stereo amps. I seems fairly well built and has XLR inputs and Speakon outputs. It actually says "PROFESSIONAL POWER AMP" right on the front, so hey, it must be good. ;)

I'm not sure if I could recommend this in any pro audio applications, but for a fixed install in a church or business, a bands rehearsal space, or maybe powering a large home subwoofer, it might be worth the gamble. I am pretty happy with it.


One thing to be careful of if anyone else buys one is that mine shipped with the voltage switched to 230 volts instead of the US standard 115. There is also a STEREO / PARALLEL / BRIDGE switch on the back that the manual doesn't explain (!!!!!!) so make sure you understand those difference before you fire it up.

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Rick Lee
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Re: GTD amps

#22 Post by Rick Lee »

40 Hz wrote:As far as voltage goes, they put out 53 volts AC (350w @ 8 ohms / 700w @ 4 ohms / 1400w @ 2 ohms) per channel when maxed out.
Late reply, but after more use I would say this is right. My amp is holding up great.

They came out with another one last month. http://www.ebay.com/itm/181177607312?ss ... 1423.l2649 I just got two delivered today for an install and if nothing else they are definitely heavy. The owners manual, which has more misspelled words than correctly spelled words lists 900 w/rms per channel into 8ohms and 1100 w/rms into 4. Judging from how big the transformer is I would guess the output is probably in that range. We'll see how they do in the next few days.
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Re: GTD amps

#23 Post by kkip »

The build quality reminds me of the Gem Sound amp that I have as a backup. An okay amp in a pinch but not something I would want to rely on too much. But if I am spending $200-$250 I would rather buy a used Peavey IPR-1600 or 3000 that weighs 7 lbs and comes from a reputable company. Heck if I wanted to lug around 35 lbs amps I'd buy used Crown xlr-402s or 602s. There seems to be a glut of those right now.
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Rick Lee
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Re: GTD amps

#24 Post by Rick Lee »

It is what it is. They're heavy so that's a big strike against them for the weekend warrior. For those on a tight budget or you can't find anything decent used, or in this case an install where they're not going to be pushed day in and day out it looks like it will work just fine.

Where I would consider them most is the smaller amp for running tops. Tops get loud without much power and these aren't being pushed hard compared to the sub amps. In this particular case the client opted to try the bigger amps for his subs because he's very satisfied with the smaller one for the tops. He's going into this with a tight budget and he is informed.

No, they're not UL listed and they don't even say where they're made so there is obviously something shady going on. But since most of y'all on here are DIY it's something to consider.
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Re: GTD amps

#25 Post by DJPhatman »

Rick Lee wrote:...they don't even say where they're made...
Zoom into the picture of the rear, right under the "CAUTION" warning label, and you will find a "Made in China" label. :?

EDIT: Correction, the "Made in China" label is on the T-4500 amp listed, http://www.ebay.com/itm/2-Channel-4500- ... 6102784%26
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
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Rick Lee
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Re: GTD amps

#26 Post by Rick Lee »

Yes, there's no doubt they're made in China, without them labeled I'm wondering which factory's back door they came out of...
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Re: GTD amps

#27 Post by KJ4BXT »

This thread was part of how I found one of my amplifiers, so I figured I'd give my take on it
I have one of the GTD amps, the TN-350. My impression of it is that it's a good subwoofer amplifier for the price. (Though given the price, that's not saying much :lol: )

I picked it because I was looking for a 1 RU amplifier that could drive both T48's to full capacity, and it does a very nice job of that.
When I measured it to set my limiters it was hitting about 55-60 V no load, but the ICL light was starting to flicker.
I'm not entirely sure what ICL stands for, I think it might be Inrush Current Limiters.
I tried the amplifier on my tops, but I wouldn't recommend it for that as it has a relatively high noise floor. It might not be noticeable in some pro sound applications, but it was higher frequency noise, like white noise, so I used it on the subs, and it's inaudible. 8)
My other amp is a QSC RMX 1450 (280 W/ch @ 8 Ohms class AB amp) and noise wise it's practically dead silent (electrically)

The GTD is also rather noisy electrically. If you are using wireless mics within a short distance of it, this might be something to consider.
I was playing FM broadcast radio for a while, and it was really hurting my reception on the weaker stations. I also had a portable amateur radio, and if I got too close it would break the squelch. (146 MHz range)

Overall I'm happy with it, it's the only sub $1000 1 RU amplifier I've found so far with enough power to run my titans, which it does nicely.
Hope that may be informative for anyone looking at these amplifiers.
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