Amp Advice

[FunkyJ]

As some of you might know, my amp blew last year, and I've been quoted $50 to get it looked at, and anywhere up to $250 to get it fixed.

Now, as that one was years old when I got it, and I've had it for about 6-7 years myself, rather than spend that money on getting it repaired, I may as well buy a new amp.

My speakers are Alesis Monitor Ones, and so I was thinking of getting the Alesis RA150, which is the "next gen" version of my broken amp, which is anywhere between $250 and $400.

http://www.alesis.com/ra150

Anyone know anything about these amps? Are they good? Will it last a long time?

Does any one know of any other decent brand of amp, and what should I look for in buying one?

[Direkt]

Yep, I know quite a bit about them

The RRP on these amps is $339inc. So you could expect to pay sub $300 for a brand new amp with warranty locally.

Anyone charging you $400 is taking you for a ride.

Our service department are of the opinion that they are a very reliable amp.

[FunkyJ]

Do you sell them?

Or know where I could get one locally?

[Direkt]

We don't sell direct to the public, no - sorry.

Any musical instrument/DJ store can get them for you mate.

If you're in Melbs, try our local store...

Or:
*Pro Light & Sound: PH. 9579 2332
*EAV Technologies: PH. 9417 1835
*Soundcorp: PH. 9694 2600
*Store DJ: Ph. 1300 858 394

[Direkt]

shutup mate

[FunkyJ]

Cheers!

But need a little more info here - I forget all the stuff I learned about Ohms and Watts :p


My speakers: Alesis Monitor ones
4 Ohms impedance
Maximum power 120W programme, 200W peak.


Current Amp: RA 100:
Output Power: 100 watts into 4 ohms, 75 watts into 8 ohms, per side
THD: 0.05% THD @ 1kHz (8 ohms), 0.19% THD @ 1kHz (4 ohms)
Frequency Response: ±1dB 20Hz - 20kHz

The New Amp stats: RA150:
Rated output:
# 4 ohms: 75 watts RMS per channel
# 8 ohms: 45 watts RMS per channel
# 8 ohms: 150 watts RMS, bridged mode
# Signal to Noise Ratio: >105dB
# Frequency Response:10Hz - 70kHz +0, -3dB
# Distortion: < 0.02% @ 4ohms, 20Hz - 20kHz
# Input Sensitivity: +4dB for rated output
# Crosstalk: -85dB, 1kHz
# Output offset: +/- 50 mV, Servo controlled

Will this amp be powerful enough, or will I need to go to the next level (the RA250)

Rated output
# 4 ohms: 150 watts RMS per channel
# 8 ohms: 90 watts RMS per channel
# 8 ohms: 300 watts RMS, bridged mode

[Direkt]

There isn't a 250 as far as I know, you must be talking about the 300 - which is now discontinued.

RA150 would probably be adequate mate, depending on how loud you run your monitors.

If you want something more powerful, perhaps take a look at Samson's Servo 200. They're around $300inc.

2 x 100W @ 4 ohms.

[deviant]

your amp should always be a little over powered than your speakers as a rule of thumb....

this thread has some good info..

http://au.answers.yahoo.com/question/in ... 637AAMvZZ8

the last guy's argument is flawed as he neglected to take into account that you can hear speaker distortion much easier than you can hear amp distortion. I wouldn't be surprised if your current amp (the broken one) blew because it wasn't powerful enough for the speakers, especially if you were listening at a fairly high volume.

[FunkyJ]

There isn't a 250 as far as I know, you must be talking about the 300 - which is now discontinued.

Yeah, sorry, I was talking about the 300... but discontinued... DOH!

I wouldn't be surprised if your current amp (the broken one) blew because it wasn't powerful enough for the speakers, especially if you were listening at a fairly high volume.

It blew because the idiot Colombians I let have a mix had too much coke and ran the amp too loud so it overheated. It was very, very hot.

I just had a thought - I've assumed it was the amp, but could the speakers both have blown at the same time? I've always assumed two speakers blowing was an incredibly rare thing, but I have no real reason why I think that...

[Direkt]

there's always the chance... but you'd think they could have withstood the power being fed into them at those ratings.

[FoundationStepper]

deviant is right, it's best to have an overpowered amp than underpowered. remember that if you are putting out max rms of say 200W at unity, then 3dB below this you are putting out 100W - i.e. being a little careful means you are running more in line with the speaker expectaions and not overdriving them

the problem with an underpowered amp is that people are more likely to overdrive the amp (clip the signal) to get the desired volume, and squarewave distortion, even at low levels is more the enemy than power.

speakers can squarewave from overdriven signal, which burns out the voice coil.

this and also being underpowered and not handling a low impedance can both stress/blow the amp

[deviant]

Square waves set the speaker on fire at the metro/palace at Spor & Ewun a few years ago.

[FoundationStepper]

bad gain structure FTL

[deviant]

makes for an entertaining night... they had a whole other back-up stack anyway... so the night kept going