Audiophiles: Using a PA as a home stereo

The other day a buddy and I were strolling around a music (instrument) store, and noticed a PA amp with an ipod docking port. My buddy thought this would make the ideal stereo system, but I disagree. At first it was because the sound quality wouldn’t be “hi-fi”, but now I’m wondering if this would really be the case. So, could one use a PA as a (rather loud) home stereo? What sort of quality differences would there be between one and a high end Bose or JBL sort of system?

Pro audio amplifiers have very good frequency response and low distortion and are equal in quality to any audiophile amplifier as long as they are connected to a speaker load within their specifications. The drawbacks to using pro gear is that the connections are usually different than what your home stereo components will have and they lack some features that are desirable in a home audio system. Also, high-watt pro amps will typically have cooling fans which will add ambient noise to your listening room.

There is no advantage to buying a larger amplifier than you need. You’re just wasting money.

As Anthony N mentions, the primary irritation will be the amp’s inputs and outputs. Rather than the RCA jacks and spring clips or screw terminals for speaker wires, expect to find either 1/4" phone jacks or 3-pin “balanced” XLR jacks on the inputs and Neutrik Speakon plugs for the speakers.

Something else that’s missing is input selectors and tone controls. The vast majority of these things are purely amplifiers. In their normal lives, input selection and tone control or EQ is handled at the mixing board.

On the plus side, you can expect a pro amp to be effortlessly powerful compared to home hi-fi. Pro gear usually has more “headroom” or dynamic power capacity than home stuff, and they’re usually somewhat “bulletproof” - short out or overload a home amp and at best, you’ll need new fuses. Pro amps are more likely to drop the power gracefully rather than blowing fuses or the output drivers. They’re also going to be (or supposed to be!) much more durable, aka “roadie-proof”) than home gear.

You might have noticed at a club, dance, or wedding that the professional DJ would probably be using a PA setup. Or even at a concert music is piped through the PA before the show?
The biggest difference, besides the good points already mentioned here, is that a PA is designed to be used at high volumes for larger venues, indoor and outdoor. They are not suitable for smaller areas or neighbours, believe me!
They are basically a straight amplifier with minimal, if any, modulaton so you might want a preamp or equalizer to adjust for tone, etc. but as Anthony N said,

…and in most cases this would be overkill.

I’ve been doing this for about 14 years. It worked great for about the first 10 years & then the PA started acting funny, suddenly losing a chunk of range & dropping in level when I was listening to a record or CD. I can put on a record now & it generally starts OK but inevitably the sound just drops out as I described. At one point a woman in a music shop determined that it was a wiring problem & rewired it, which fixed the problem for a while but then it started happening again. Probably just something unique to my PA; nothing to worry about.

I have EQ adjusters right on the PA, so that was never an issue. One cool thing is that my PA also has effects like echo and reverb that can be applied to whatever I’m listening to. By fiddling around with the dials you can make a normal recording sound very very weird. A major drawback with my setup was the fact that the PA is not split for stereo, so I’ve been listening to everything in mono - same signal thru both speakers. So, obviously, know whether your PA is stereo before buying. Aside from that, I’d say the sound I get (or used to get) is as good or better than a regular expensive stereo system. You just need to get some RCA to 1/4" adapters, as others have alluded to.

As an addendum to what I said about the mono/stereo problem, even if you have a “stereo” PA, it might have inputs only for single 1/4" plugs, so in effect you’d be sending a mono signal to the PA to start with. For example, the way my setup goes is -

CD player => stereo RCA plugs => RCA to 1/4" adaptor => 1/4" input on the PA

So the signal is coming out of the CD player in stereo but going into the PA in mono.

What is a ‘PA’?

A power amplifier. It takes signals such as vocalization via a microphone cable, or a musical instrument via an instrument cable, or recorded music through a connecting cord, and makes these things loud. It then sends out the amplified signals to speakers.

In this context, a “PA” (system), is a public address system. But yes, it’s also a power amplifier, but that’s not what the acronym stands for.

Public Address.

Public Address systems are used to spread sound (usually voice, but also music) around to large(ish) crowds. Originally, PA equipment’s main property was that it be loud and tough. Quality was definitely a secondary consideration.

These days, electronics in general have gotten generally very good, and PA is now commonly used by many people to include the equipment used by musicians in public performances. So PA equipment is often now quite good quality.

Public address, actually.

I have a PA and my amprack includes an old Alesis 3630 compressor that I need for about 10db of extra audio to get everything out of my amp (Ramsa WP-1400). This item adds an unacceptable amount of noise to the mix for small spaces and lower volumes. Without it, everything is clear as a bell and still manages to crank the Mackie C300i’s.

PA’s generally aren’t used for surround sound, so there’s that feature that makes a huge difference in a home audio setup in terms of what you hear “matching” what you see.

However, as just a blastingly loud stereo system, you’ll be creating mini-earthquakes given enough power and appropriately sized speakers and woofers.

My beat-up old setup consists of a 400w 2-channel amp for the main speakers, a 200w 2-channel amp for the monitors (those speakers that sit on the floor at an angle) and a modest 8-channel mixer board. It blows doors as the basement stereo–but there were times when my monitor amp and/or speakers formed the basis of my living room stereo and were kickass in that capacity as well.

You just need the right connector adaptor dohickeys from Radio Shack.

Thank you, Bagistan, RJKUgly and jnglmassiv.

To FoieGrasIsEvil; the PA system of almost every movie theater is very well suited for surround sound.

Now back to the OP; what the f### are you talking about?

PA as an abbreviation for “public address” dates back to old Tannoy systems and the sorts of weedy setups used in meeting halls and such, but we still used it to describe the 20kW rigs we used to run for raves. So what a “PA” is depends a lot on context.

As a former PA* owner I have had occasion to try some (fairly modest in sound system terms) Turbosound TMS 2s (pdf link) powered by an 800W C-audio (for bass) and 400W Hill amp (mid/top**) as a “home stereo” and to say that was over the top would a bit of an undestatement. You’re look at FoieGrasIsEvil’s earthquakes here. You will be disturbing the neighbours.

As a sensible answer to the OP. PA amplifiers are perfectly good as home system amps (though “audiophiles” wouldn’t say so) with loads of spare power for transients but as Anthony points out anything bigger than about 300W will have cooling fans (like a PC power supply). PA speakers not so good for home use, loud and good is expensive and potentially complicated with active crossovers and such.

  • fairly substantial systems, not just a big amp and a couple of cabs.

** the TMS 2 is (was) bi-amped with a passive crossover for the “tweeter” horn.

When you get into the “audiophile” world, you hear a lot about warmth, soundstages, depth, smoothness, and other subjective terms to describe the sound of equipment. Many would like to claim that the differences in better (rediculiously expensive) gear can’t be measured, only heard by a trained ear.

The reality however is that we can very precisely measure how accurately an amplifier can reproduce the input signal and even very inexpensive amplifiers have distortion levels that would be inaudible to even the best ears. Distortion in this case is defined by the amount of difference exists between the input and output signal aside from the voltage increase.

Audiophile-grade amplifiers are generally built with esoteric components and operate in a wasteful class-A mode. Pro audio amplifiers strive to maximize power while retaining high energy efficiency and reliability. Switchmode power supplies reduce the weight and size while newer class-D technology can deliver huge power with very high efficiency.

De-rail. . .

You hear a lot of bollocks of course. A properly designed amplifier doesn’t have (and shouldn’t have) warmth* or smoothness, whatever, the output waveform should look exactly like the input. And the output should be able to cope with vagueries of speakers (output impedance, damping factor, blah) PA amplifiers can be extremely powerful** and I’d rather have the extra headroom (from higher rail voltages, bigger power supply) you get in a big PA amp than 0.0001% THD and “musicality” in a puny 200W audiophile box anyway.

*let’s leave out valve amps

**We had a Hill DX-3000 that would drive 3000 Watts into a 2 Ohm load. If there is a ‘home stereo’ with that much power then…(better check) OK Googling didn’t turn anything yet but I did find an “audiophile” amp with a quoted frequency response stated “DC-50kHz” W.T.F? DC, You going to use the thing as a power supply or what? And who’s listening to 50k? Idiots.


We all are.

I was going to reply to this but you beat me to the punch!
Good job!

Ultrasonics being dropped are also one of the reasons for the lower quality of lossy audio data compression formats such as MP3’s, etc.