108 replies to this topic

[SomeFReaK]

Hi Guys,

Looks like my old faithful Jaycar amp has a dirty channel, so rather than repairing it (again) i think i want to replace it. What i am after is opinions on what amps i should be looking at to run my dynaudio's (240gt's). This is obviously for SQ, but i want to make sure that whatever amp i end up getting has similar power output to the jaycar (2X150) so i dont loose any volume. I am looking at a budget of around $500, which could blow out a further $200 or more.

[Fhrx]

There are many different amplifiers out there on the market. Some to look for include:

Audio System F2-300
http://service.winnet.it/Gttrading4/easysi...udio_system.asp

Crossfire VR302
http://www.crossfirecaraudio.com

ARC Audio 2100XXK
http://www.arcaudio.com

Audison SRx2S
http://www.audison.com

Boston GT22
http://www.bostonacoustics.com

Zapco Reference 350.2
http://www.zapco.com

Vibe BlackboxII
http://www.vibeaudio.co.uk

That is a start. Other people will add to that list. Remember too that power is not the be all and end all of amplifier performance. There are other stats to look out for before power. Things like damping factor, slew rate, S/N ratio, separation and THD just name a few.

Edited by Fhrx, 21 April 2006 - 11:05 AM.

[TUN35]

I currently run mine off a zapco 350.2. Goes quite nicely, but i would like a bit more headroom. If you were to stretch your budget to $800 you can pickup a Zapco 750.2 currently

[Juls]

I can't tell you which amp to buy,

I can suggest some ideas for specifications to look for.

Slew Rate at least 25 to 50 uV + Slew rate roughly effects how fast the amp can change voltages, higher number means more precise midrange and high frequencys, Low Slew rates can often make tweeters sound Harsh or bright.
Damping Factor at least 200-500 + This effects how much control and precision there is over your midbass, This is usualy more effective for subwoofers, but it can help how strong and fast your Midbass will appear.
S/N Ratio at least 90 DB, preferably over 100db + This refers to how loud the amp reproduces clear signal from noise, a higher number will mean cleaner overall sound.
Separation at least 80-95db + This will effect how good your imaging can be, and how well left and right music signals are separated from each speaker.

THD refers to the amount of distortion at the power rating.

IE: if One amp has 150W RMS @ 10% Total Harmonic Distortion
then the next amp has 150W RMS @ 0.02% THD..

then the amp rated at 10% THD probably really only has maybe 100 or 120W RMS @ 0.02% THD.

and the 0.02% THD amp probably really has more like 200W + at 10% THD.
Thats just a ROUGH EXAMPLE to give you a idea, it is NOT ACCURATE!! every amp is different.
so you idiots who don't read stuff properly can keep your silly remarks, ideas and opinons to yourself.

anyway really choose how much power you need, and look for the lowest Measured Distortion,
and you'll actually get more power for your money. I would be tempted to go for a amp rated at 100W RMS @ 0.02% THD before a amp rated at 125W RMS @ 1% THD.

Also Look closely at what Voltage they are tested. The most realistic voltage is 13.8V, which is about what you get with the car running with 1 quality battery under full audio system Load. 14.4V is unrealistic, unless you have a Kickass Alternator, and 2 batterys. 12V is also good, if the rated power is at 12V, often you'll get 5-25% more power with the motor running as the voltage increases.

People are gonna jump around telling you, that you can't tell the difference between amps just listening,
many people can tell the difference, but the only real way to tell is to get one and install it and use it for a good 2-3 weeks, then get another amp and swap and run it for another 2-3 weeks.. it can take time to listen to all your favorite songs and pick up on the little things that sound different. usually back to back you miss these differences because you can't instantly just take information like that from your Pre and especially Sub Concious. I've always noticed massive differences between amps I've used, the worst amps I have had where crossfire amps surprisingly, plenty of power but they just sound poor and lacked control. Especially when you compare them to the equivalent soundstream or similar.

Never buy a amp and expect huge wonderous differences immediatly. It takes time to fully appreciate the differences, it's worth it in the long run to have a nicer amp especially behind nice speakers. The search for perfection.. never ends.

Regards
Juls

Edited by Juls, 21 April 2006 - 02:29 PM.

[SomeFReaK]

thanks for the responses. I was aware of the THD rating, but hadn't heard of slew rates. I guess this post was more to get an idea of what manufacturers make amps that are geared towards SQ and at fairly reasonable prices.

[LexARSE]

Around that price id be checking out the arc audio amps, or maybe look second hand and see what you can find.

[HooDs]

Timmy check out some audio system gear.....

If that doesnt suit you, drop your battery terminal nuts down your engine bay.

Edited by HooDs, 21 April 2006 - 04:27 PM.

[Damo95]

not trying to push anything, but i have a 4 channel amp which would run the 240GT's nicely, with 250wrms a side.. and is on your budget.. or use 2 channels for these and the other 2 bridged for a sub..

either way, a high quality 2 channel would be good.. i remember i had my old 240GT's running off an audison LRx 2.500.. 200wrms a side and loved every bit of it..

[MADTRAV]

for your money

Alpine Mrvf345, Boston GT22-40, Rockford p4004, Eclipse ea4000, Clarion APA4320?(last years top of range made in usa ((actually its an older ARC with modified heat sink)) 4 x 80Wrms really an awesome amp no one talks of)

Many to choose from

[shiny_car]

SomeFReaK, on Apr 21 2006, 10:05 AM, said:

i want to make sure that whatever amp i end up getting has similar power output to the jaycar (2X150) so i dont loose any volume.

with respect to this, ask yourself 2 questions:
1. did i clip the jaycar amp, meaning, did i fully utilise all 150WRMS it can offer? if not, then you don't need 150WRMS
2. how much volume difference is there between 150WRMS and 75WRMS? around 3dB. i can easily demo this to you cos my HU's volume control is calibrated in dB (rather than just numbers), and 3dB is NOT MUCH

as such, i would strongly suggest 'quality over quantity' if you have the choice and limited budget.

sure, a higher powered amp has more 'headroom'. however, i would argue that headroom is factored into 'peak power output', and a high quality amp will have a truly high peak power output to cope with the dynamics.

Quote

I am looking at a budget of around $500, which could blow out a further $200 or more.

how about the boston acoustics GT20 RRP$499?

[brady123]

GT-20 is only 2x45W, which is fine is thats all you are going to use but a little more headroom couldnt hurt. Although the Boston amps are very nice, I think there is better value for money. The SRx 2S or F2-300 that Marty recommended would be my picks (Im going to run mine with an SRx 2S - assuming its still for sale by that time).

Edited by brady123, 21 April 2006 - 06:41 PM.

[SomeFReaK]

Quote

If that doesnt suit you, drop your battery terminal nuts down your engine bay.

Sounds like fun, might give it a try

shiny_car, on Apr 21 2006, 06:34 PM, said:

with respect to this, ask yourself 2 questions:
1. did i clip the jaycar amp, meaning, did i fully utilise all 150WRMS it can offer? if not, then you don't need 150WRMS
2. how much volume difference is there between 150WRMS and 75WRMS? around 3dB. i can easily demo this to you cos my HU's volume control is calibrated in dB (rather than just numbers), and 3dB is NOT MUCH

Very true, i wasn't clipping the jaycar at all (i set the gains with a CRO) so i probably dont need the extra power. Food for thought indeed!

[808]

can the clairion really compete with the likes of boston or alpine in sq and build quality? as i believe internally they are very similiar to arc amps as madtrav said and they have a good rep. because at a price point for power they seem good value as well as the crossovers seem to be very adjustable.

[PHD]

it doesn't matter how much power you can get from your amp. the matter is how much clean power you can get from your amp specailly for your SQ system.

[shiny_car]

brady123, on Apr 21 2006, 06:40 PM, said:

GT-20 is only 2x45W, which is fine is thats all you are going to use but a little more headroom couldnt hurt.

quite true. i chose this baby amp to demostrate my point. too extreme maybe.

however, i would expect the performance to 'sound' more than just 2x45WRMS. but i'd have to have someone like MADTRAV (who sells/installs boston) to comment on that.