QSCGXD8 Class D Power Amplifier with DSP

My adventure with these 2 amplifiers started with 40 year Phase Linear D500 developed a noise problem from leaky capacitors. Since my only local Vintage repair shop went out of business, I decided it was time to see what new innovations were available. My first foray was with the GXD 4. First impression was being blown away with the amp’s power efficiency, quiet fan and dead silent audio at idle. However, I was equally disappointed with the amp’s lack of dynamic range, and lack of Bass response and “punch” when used with full-range speakers. It almost sounded like a low pass filter was engaged, but the DSP menus assured me all filters were set to “Bypass”.Not wanting to give up, I decided to order the QSC GXD 8. What a difference!! I was completely blown away. The GXD 8 has the same quiet fan and noise floor as the GXD 4, but delivers full dynamic range and bass punch at any volume. Who would have guessed a class D amp could deliver near sub-sonic house shaking Bass that I thought was only to be found in old Vintage high-conductive transistor amps. The GXD 8 actually outperforms my old Phase Linear, in part because it delivers it’s huge Bass at nearly 85% power efficiency. Volume levels that would sag my home’s 15 amp circuit on the Phase Linear just sails by with the GXD 8. My only concern is this wonderful amp is being built in China, with circuit designs that might not last for decades (like My Phase Linear did). But for now, this aging baby boomer is in audio heaven...QSC GXD 4Pros>Whisper quiet fan when in idle. You have to be near the amp to hear it.>Residual noise is almost inaudible at idle, even with your ear right up to the speaker.>Only about 25 watts idle power consumption. Great for continuous use.>No in-rush surge current when powered on. Power up is smooth.>The DSP LPF settings include “bypass”, which removes the 20hz block filter found on other amps.>Very clean sound, but problems with Bass and Dynamic range (see below).>Useful as a side/rear channel speaker amp.Cons>Lacks both response and dynamic range in the Bass end below 100hz. You can partially restore the bass weakness with the DSP EQ, but the amp still completely lacks Bass “punch” so necessary for Home theater.>Not recommended for sub-woofer use.QSC GXD 8Pros>Whisper quiet fan when in idle, and only marginally louder when the amp is run at ½ power.>Residual noise is almost inaudible at idle, even with your ear right up to the speaker.>Consumes about 55 watts idle power consumption, and approaches 85% efficiency above ½ power.>No in-rush surge current when powered on. Power up is smooth.>Exceptional sound, dynamic range, and especially good Bass punch which the GXD 4 lacks.>The DSP LPF settings include “bypass”, which removes the 20hz block filter found on other amps.>Perfect for large power hungry front full-range speakers, or sub-woofer speakers.Cons>Power-on triggers 2 audible relays, which might become a reliable issue long term.>The entire unit is made is China.>The power supply design is like what you would find in a high-end computer. The reliability record on computer power supplies made in China is usually measured in years and not decades. Only time will tell if higher standards were used in building the GXD 8.

I am using this to power a pair of Ciare 18" subwoofers in large ported cabinets. For the past fifteen years I was using a pair of RMX850's, which were- yes- too small. Under such a load, these amplifiers ran hot, with fans running at full speed, even at moderate volume levels.This new amplifier is much more powerful, far better headroom, and the bass is much "tighter" than before. Very noticeably, this amp doesn't get hot, even with the sound level cranked up. Does it even have a fan? I don't see one. It may be fully passive-cooled.This amp has many built-in preprocessing features including a programmable crossover. A lot of amplifier for the price. QSC is putting a lot of effort into Class D amp design and it is paying off. I would buy again.

Muy potente, a pesar de su peso tan liviano

A solid buy. Purchased this amp in February for my mobile DJ Service for use in my smaller setup. It has been reliable at over 10 events with no issue. Looking to buy a second for another system.

Today its out of the box brand new. GXD 4, Unit is on, & sounding good. Having been thru 3 amps, from various other companies. Over the last 4 years, I reccomend getting the extended product protection plan. This time I will remove one of my 4 speakers to be sure I do not exceed the limits. It is not easy to know if my Yamaha speaker is too much for channel A. Yamaha , model s115. speaker limits: 8 ohms, 500 watt with a max of 1000 watts. So maybe if if do not crank up that channel A, it may hold steady at no more than 500w? The other side, channel b, it has 2 house speakers at 250 Watts, and 350 watts. Its sounds plentiful & perfect, and no fan noise , no humming buzz sounds.

Didn't purchase on Amazon, but this amp works great. Using the built in DSP and saving it as a preset saves a lot of headache. This leaves the fine tuning to my mixer rather than using the mixer for everything.

I received the Amp in a well and nicely packed box. However, after I plug in the power cable and set up everything ready to roll, the Amp can not be powered on.....There was a message showed system failure. Seriously, this is the first time I bought electronics from Amazon and felt frustrated that it is a defective item. Asked for a replacement from Amazon and will seeUpdate 07/23/19.This item can not be replaced at Amazon, so returned the first one and placed a new order for the second one. Received it on 07/23/19 and hook up all cables to my speakers. Powerd on without any problems and weired thing happened! I only got Mono sound from one speaker....I checked my music source and was damm sure it's Stereo format instead of Mono. I checked my mixer console and all wires/cables, and nothing wrong I can find. I disconnected GXD 8 and hook up to another old Amp. Man!! The Stereo sound came back ! I checked the GXD 8 and it showed configuration is Stereo mode but nothing I can do . I was very frustrated and realized I might get anoter defective unit....I only have to return it. End of story and this brand....