Axiom Home Page Forums General Discussion Advice from Axiom Owners Pre-Amps and Amps questions.

Hi Everyone:

I have a couple of questions about pre-amps and amps that I hope someone will answer.

I have a Denon avr3311ci, M80s, vp180, qs8s, and a crappy sony sub from and old HTIB.

My questions are what is the purpose of a pre-amp?
2) will an external amp make my speakers sound better?
3) if I were to buy an external amp what would I buy a mono, stereo, etc?

I have looked at this and other forums and there is lots of information, however I have not found a simple dumbed down answer. any information will be greatly apreciated.

Paul

1. A pre-amp generally does the processing and selection of inputs. You can consider it to be equivalent to a receiver without a tuner and the final amplification stage.
2. A good sub is far more likely to make your system sound better.
3. You would buy an amp with the number of channels you would like, or multiples thereof (in other words, 5 mono amps for your existing speakers, or 2 stereo and one mono, or a 5 channel, or a 7 channel...)

The preamp takes all your audio sources like Blu-ray, MP3 player, TV etc… and:
- Does the switching i.e. selects the input you want to watch, say TV.
- May do Digital to Analogue conversion
- Does equalization (bass, treble, room equalization etc…)
- Handles the volume control
- Does any channel mixing (eg. Stereo to DTS Neo 6)
- Adjusts the voltage of all the inputs to an appropriate level
- Finally, send the audio signal to the Power Amp

The Power Amp is what amplifies the audio signal and drives the speakers. Most AVRs have built in power amps and can typically drive 5 channels (L,R,C,SL,SR). This is convenient because one unit does it all. However there is a tradeoff.

While AVRs may state that they can output 5.1 at 100 watts per channel for example, they cannot actually output 100 watts simultaneously to all 5 channels at the same time. My Denon 4311CI claims 140W to 7 channels but read the fine print and you will find it can only drive two channels simultaneously at that power. The AVR power supply simply does not have the capacity to do so. If you are like me and like your explosions loud, you may be disappointed.

In addition, if you drive you AVR beyond its capacity (which is easy to do) it may go into clipping which is very bad for your speakers and will ultimately damage them.

So what to do if you want louder explosions? You go with external amps. I use a 3 channel ADA1000 to drive my M80s and VP150. My Denon just needs to drive my two surrounds and two rears. It all sounds pretty awesome.

The catch with using external amps however is that you're AVR must have Pre-Amp outs.

I hope this helps clear things up a bit.

I still say that his money will be better spent now on a (much) better sub than an amp. That way you'll definitely get better explosions.

+1

Absolutely. That made a vast improvement for me in the overall sound and "enjoyability".

As JohnK always says, unused headroom is exactly that: a waste of all resources. You know that he'll chime in later.

I'd also say that your room size may play a factor here. I've got under 2K cubic feet in my room and my Onkyo receiver is plenty loud enough thank you. Large rooms - I mean huge here - are obviously different animals, and would need more assistance/power. Simple physics.

I really don't understand some of the folks here who have small rooms and seem to want to continually jeopardize their hearing. Mine's at risk from health treatments and I've been suffering with tinnitus for a over year now because of a single treatment of a drug last summer. It's really very uncomfortable. Be reasonable and protect your hearing. </dismounts soapbox>

+n to what our other friends said.

If you want your "system to sound better", before spending money on an amp, I would:

-Get a new sub
-Experiment with speaker placement
-Experiment with wall coverings or sound treatment

I don't know how loud you are listening, how big your room is, or what content you're consuming. It's unlikely that the amplifier section of your receiver is the weak link in your system, or that buying a new amp is going to make the biggest difference for the money.

I bought a 3-channel amp for the L/C/R channels because it made me happy. I'm pretty sure it did NOT make an audible difference for the overwhelming majority of things I watch/listen to. But I'm still glad I did it.

Buying new electronics is always fun, but I agree with the above. Unless you need to fill an abnormally large sized area, there is a lot of other fun stuff to be had that will prove a better bang for the buck.

Friends don't let friends buy preamps when they could buy a really big sub to annoy the neighbours with?

Most rooms will do fine with a receiver rated at 90-100 wpc (two channels driven).

Most of the time, you are going to be using less than 20 watts to enjoy your system at a reasonable listening volume.

The exception is when your system is in a very large room AND you are listening from further away. In most cases, I expect that the listener is going to be in the range of 10-12 feet from their speakers.

Get a better sub so you can really enjoy the deep rumble in all those awesome action movies.

2) no, it won't... amps "Should" simply amplifier the input signal. However, is another topic all together.. The simple answer is no....

3) in my system i have 3 amps. 2 stereo amps, and a three channel amp.

My small my stereo amp is rated to 500W @4ohms, as is my three channel amp. My second stereo amp is rated for 1,200W @ 2ohms...

My "small" stereo amp/three channel amp weigh about 50-60lbs.. my "large" stereo amp weights about 110lbs...

I am sure JohnK will chime in here, me and him have polar opposite opinions to your question.

I have the amps i have for 2 reasons.. one, because my previous 5 channel amp was being driven into the clipping region on a couple channels (indicated by the clipping lights lighting up like a Christmas tree), so i bought bigger amps... The other reason, because i wanted a big amp, and i could afford it, so why not... Right?