Technical Questions

MPH 6300
MS/MPS Amplifiers
MS Special Edition
M Amplifiers
M Special Edition
QX  Amplifiers
Sapphire Amplifiers
XS Amplifiers
ZPA Amplifiers
ZX Amplifiers
ZX Special Edition
ZXti Amplifiers
Technical Questions


How much power does my ZX, ZXti, XS, or M series amp put out at two ohms bridged?

All three are designed to make the most continuous power at 4 ohms bridged or 2 ohms stereo. They will make slightly less CONTINUOUS power at 2 ohm bridged loads, but PEAK power increases at 2 ohms bridged. The lowest impedance you should ever run on a ZX, XS, or M series amp is 2 ohms bridged or 1 ohm stereo. Phoenix Gold knows that people will connect these loads to the amp so they build them to take it. It's important for each design to continue playing even when abused.

However, there are limits to how much power each design is allowed to make. The design must be able to dissipate the heat generated by the power it produces. If you can't get rid of the heat, the amp will destroy itself or if properly designed, thermal off before anything breaks. So the M, ZX, and XS series amps all have circuitry that limits the power output (and heat stress) for any musical signal longer than about 50 milliseconds. Now it's important to understand that musical peaks are much shorter than 50 milliseconds. So that means you do get more power when bridged into 2 ohms than you do at 4 ohms bridged FOR MUSICAL PEAKS (more headroom). So with M, ZX, or XS series amps with low impedance loads, put a couple of cooling fans in your install to move some air through the heatsink and it should be just fine

Also, lowering the impedance will cause the amplifier to demand more current. This often leads to a drop in voltage from your car's electrical system. The drop in voltage puts stress on the power supply of any amp. That's why thick power/ground wire and an appropriate size capacitor are a must for high power applications to keep voltage from fluctuating.

By the way, ZPA series amps simply switch into high current mode automatically and continue to give more power down to 1 ohm bridged or 1/2 ohm stereo. The ZPA's make more and more power until it thermals. But with two dual speed fans it's pretty hard to do.


I hear that Phoenix Gold Amps are underrated. How much power do they really put out?

Measured on a test bench most Phoenix Gold amps continuous power is underrated by about 5 to 15%. The higher lines of amplifiers are more likely to be underrated, where the lower lines are more accurate to the specs. But keep in mind, there is more to an amp then just what the power output is on a bench test. The higher line of amplifiers, regardless of the power output, the more solid the build, beefier, and more audiophile parts are used. The higher lines will also usually have better features such as RDDP ports, variable crossovers, fans, etc. Most importantly, the beefier high end amps are better able to handle the peaks of the music which will allow for more headroom, rarely is this taken into account when actually measuring output of an amplifier. Of course, this is fairly subjective because some listeners claim they can hear a difference between two amps with similar power output but from different lines (ie, qx2350, XS2300, ZX250). But there are people can't tell the difference. The important thing is for the individual to audition them and see if the extra money for more audiophile components, a beefier build, and extra features on the amp are worth it.


What will happen is I run my amp lower than their minimum stable impedance?

Phoenix Gold amplifiers are some of the toughest around, but its better safe than sorry. Running you amp at the low of impedance will cause the amp to draw a lot of current and create excess heat. If your car's electrical system can't provide enough current or the amp creates more heat than it can dissipate your amplifier will engage its protection, but this doesn't always happen. In some occasions, your amplifier can be damaged by not taking the proper precautions.

If an amp is rated to handle 4 ohm bridged, then it can handle 2 ohm stereo. It's the same total power. The minimum stereo load is always 1/2 of the bridged capabilities. Each amp channel must deal with 1/2 of the total load (1/2 + 1/2 = 1). So whether it's running 2 ohm stereo or 4 ohm bridged, the amp responds to the load the same. That's why you see power specs like 200 watts x 1 at 4 ohms bridged OR 100 watts x 2 at 2 ohm stereo. It's still 200 watts.

If the amp (ZPA,MPS) is designed to run 1 ohm bridged then there should not be any thermal problems with that load. The problems you see people having all the time with amps overheating and frying parts is typically due to the fact that they run 1 or 2 ohms bridged on an amp designed to run 4 ohms bridged. This makes the amp attempt to make more power but typically, it cannot because there is not a big enough power supply in the amp, the existing heat sink is too small or the car has an insufficient electrical system. So the amplifier runs hotter and pulls more current from your car in the attempt and the additional stress breaks parts.

Bottom line is if you want to get 1,000 watts, then buy an amp rated at 1,000 watts for the load you have. Don't buy the 500 or 600 watt amp that's designed to run a minimum 4 ohm bridged load and then bridge it at 2 ohms.


Where do I mount my amplifier to avoid heat problems?

Mount the amp with the heatsink fins running vertically if the amp is physically mounted vertically (ie in the trunk on the back seat). This allows a chimney effect to let the heat rise up, without having to travel through the amp or the other horizontal heatsink fins. If the amp is mounted on a flat surface, just make sure it has several inches of clearance above the heatsink to allow the heat to dissipate. When mounting a fan always have it blowing air parallel through the heatsink fins and remember hot air rises.


Why would I buy a ZXti rather than a XS if the XS puts out almost as much rated power?

I am sure you've seen the obvious differences in their appearance, the fact that the ZX has a built-in cooling fan and a variable crossover. But internally is where the biggest differences are.

The XS series was designed to compete in the largest segment of the amplifier market by providing a good solid amp design at a reasonable price. The power supply is tightly regulated to help it make predictable power with a wide range of battery voltages. So if your power wire is a bit small and you don't invest in stiffening capacitors for most applications (this is typical with many do-it-yourself installations), the amp will still put out its rated power. The only compromise is that musical peaks can't be allowed to tax the amp's power supply very much. So you could say that the amp has a limited amount of "headroom" for musical peaks. Musical peaks are sometimes referred to as musical transients or dynamics. Musical peaks typically last less than 20 milli-seconds. At high volume on the edge of audible distortion, a tightly regulated design will have a slightly more brittle and harsh sound as the power supply runs out of energy and clips the musical peak. Of course if you get a big enough amp, the speakers won't need to tax the amplifier to its limits and this harshness is never heard. And the ability to hear the difference between the two lines of amps is very subjective.

The ZXti amplifiers have a very loosely regulated power supply and lots of headroom for musical peaks. These musical peaks demand high instantaneous current from the car's electrical system so a good power delivery system including stiffening capacitors is highly recommended. At high volume on the edge of audible distortion, a loosely regulated design will clip softer and keep a warmer, less brittle sound. However, it does cost more to build a loosely regulated design. Thus the difference in price. We added the cooling fans to the ZXti amps because of the extra heat generated from this type of design. It's either the fan or a larger aluminum heatsink and if there's one thing today's market demands, it's big power in a small size.


I noticed that my Phoenix Gold equipment is listed that it can only handle 2 volts of input signal, so will it be okay to use my PLD1 to drive 8 volts of signal to my amp or processor?

Since music is dynamic with peaks and valleys that allows a lot more leeway with input signal voltage. Music is not like a test tone (which is normally used to test equipment), so in reality any Phoenix Gold equipment will accept 8 volts of signal. So if it says Phoenix Gold it will handle 8 volts of signal, no problem.


How much are my older Phoenix Gold amps worth?

Just like any piece of used equipment it is only worth as much as the market will bare. So its only worth what someone will pay for them. We have no set values of depreciation for any type of used equipment.


My Phoenix Gold has a terminal on the power plug called DR. Whatís it for?

The DR stands for Delayed Remote. This terminal sends out 12 volts 3 seconds after the EQ turns on. You can use this to delay the turn-on of your amps. If a pre-amp component sends out a pop or click sound when first powered up, this will make sure the amps turn-on after the pop so you (or the sound quality judges) donít hear it. The DR output can safely turn on up to 8 pieces of equipment.


Iíve heard that when you bridge an amplifier at 4 ohms, the amp really sees half that. It seems to me that a 4 ohm woofer canít magically change into a 2 ohm load! So whatís the deal?

That sayingís been around for years. Imagine a bridge spanning a river. If the bridgeís only support is each bank of the river, then each river bank must support 50% of the load. So a more correct statement would be that each channel sees (supports) half the load. In this case 2 ohms. This is also why you see amp specs that say 100 watts x 2 into 2 ohms stereo and 200 watts x 1 into 4 ohms bridged. 100 + 100 = 200. This is also why the minimum per channel load an amplifier can play is always half of the bridged spec.


I need a manual for my older amplifier or EQ how do I get one?

We have almost all of the older manuals on file.  We can transmit them to you in Adobe PDF format via email, Fax, or US Mail.  Contact with the make and model of the equipment.  


Is Phoenix Gold Headquarters located in Phoenix, Arizona?

No, Phoenix Gold is located in lovely, but rainy Portland, Oregon. You can reach them by calling 503.286.9300 the website is www.PhoenixGold.Com.


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