PDA

View Full Version : Need to connect laptop directly to power amp. Is this what I need?



DJ Ranga
03-28-2012, 07:57 AM
Hey guys,

I want to use my Yamaha P3500s amp which is powering a 15" sub directly with my laptop, mainly if I just have a few mates around and want to crank a playlist. Usually use my American DJ mixer which has a pre-amp built in, but rather not lug this around. Obviously, my laptop doens't output enough gain, so I need some sort of gain booster. Is this DI Box what I need?

https://www.storedj.com.au/products/BEH-DI20

Or should I go for a proper external sound card or interface?

Cheers.

Bill Fitzmaurice
03-28-2012, 07:59 AM
Obviously, my laptop doens't output enough gainThat's not true. I drive power amps with my laptop all the time.

DJ Ranga
03-28-2012, 08:09 AM
The Yamaha P3500 needs a pre-amp, and a considerable one at that. Even my American DJ mixer has some issues keeping up. Max volume on my laptop soundcard is not very loud and no-where near to driving the amp to it's full potential.

Note, using 1/4" unbalanced inputs, (converted from a 3.5mm jack) if that makes and difference...

highjump
03-28-2012, 08:38 AM
Me too... I've also ran laptop to amp "qsc plx 3602 and qsc rmx5050" directly using 3.5mm to 1/4 cable with no problems.

DJ Ranga
03-28-2012, 09:11 AM
What the...? Are you capable of driving your amp to clipping though?

Bill Fitzmaurice
03-28-2012, 10:49 AM
What the...? Are you capable of driving your amp to clipping though?
I am.

Gjhowe1
03-28-2012, 03:24 PM
The output coming out of a laptop sound card should be more then enough to drive an amp. I can clip both my woofer and powered tops with the single level. If your getting low volume there is something not right with your equipment or the signal chain.

DJ Ranga
03-29-2012, 02:07 AM
This doesn't make sense to me. I made a thread ages ago and people were suggesting a preamp, eg. my mixer, to drive my amplifier. The amp runs a subwoofer running at 8-ohm bridged. My amp has always worked like this since I got it. Has anyone else used Yamaha amps? From memory, it required +4dbv inputs.

DJ Ranga
04-05-2012, 01:55 AM
So no-one can help me out?

wilson
04-05-2012, 07:45 AM
This what you have? http://www2.yamaha.co.jp/manual/pdf/pa/english/amp/P3500E.pdf

DTR
04-05-2012, 02:30 PM
Not exactly on topic, but I recommend you do get an external USB soundcard. Built-in soundcards are generally turd. And I agree with the others, you shouldn't need a preamp.

wilson
04-05-2012, 03:12 PM
I've never really looked at the input sensitivity - as I've never had a problem. But, looking on my equipment most states a +2 to +4 sensitivity input at the center of the level control or -32 to -40 at max. His amp does look to need +4 at max, thus needing +40 at center essentially? Or am I reading this wrong?

If that is right, that seems to be a lot out of an internal laptop sound card???

wilson
04-05-2012, 03:23 PM
Eh, my bad. Just seen that iPods have at least 90+ db output. Hook one of them up real fast and see how it performs. Either your laptop soundcard is REALLY crap, or something else isn't right...

ampnation
04-06-2012, 09:39 PM
Not exactly on topic, but I recommend you do get an external USB soundcard. Built-in soundcards are generally turd. And I agree with the others, you shouldn't need a preamp.

Actually, I think it is on topic. The OP needs to be using an external soundcard. Using the same site as linked, I found this...
https://www.storedj.com.au/products/MAU-MOBILEPRE2
I have a couple of these (can't find right now... thinking stolen) and they work great, giving you balanced outputs to go to your speakers.

DJ Ranga
04-07-2012, 08:35 PM
Agreed, integrated audio generally sucks. I've never used the balanced inputs or outputs on my amplifier, only unbalanced. Perhaps it's time to change that. As far as the soundcard goes, it has no issues. I usually have this hooked up from my Asus Xonar D2X soundcard which shits all over iPods as far as output and SQ goes still can't drive my amplifier to clipping. I've tried multiple sources too. Perhaps using balanced inputs would help.

Here is my amplifier manual: http://download.yamaha.com/api/asset/file?language=en&site=countrysite-master.prod.exp.yamaha.com&asset_id=3028

DJ Ranga
04-23-2012, 05:16 AM
Should it matter whether i'm using balanced or unbalanced inputs? I thought they were pretty much electrically the same, balanced just has additional shielding properties I thought? Perhaps I will see if using balanced inputs (going to have to borrow something to test) makes a difference. I was considering an external soundcard though, i'm using my mini desktop for DJing at events as my desktop has a decent sound card, but external with my laptop would be great as its much smaller.

ampnation
04-23-2012, 09:05 AM
Should it matter whether i'm using balanced or unbalanced inputs? I thought they were pretty much electrically the same, balanced just has additional shielding properties I thought? Perhaps I will see if using balanced inputs (going to have to borrow something to test) makes a difference. I was considering an external soundcard though, i'm using my mini desktop for DJing at events as my desktop has a decent sound card, but external with my laptop would be great as its much smaller.

If you have the option of balanced or unbalanced, always choose balanced. Using an external soundcard will be an improvement over a laptop's internal soundcard almost always and enough so you should be able to immediately tell the difference IMO even without it being balanced. However, when there ARE electrical noise issues causing a deterioration of signal, unbalanced can be a worse problem than using an inferior soundcard. It won't be an issue until it is and when that happens it could be a mild problem, or not so mild. Also, if your signal runs are short -- under 6 or 10 feet or so, you should usually be fine. Anything over 10 feet and I wouldn't feel comfortable using unbalanced.

DJ Ranga
04-23-2012, 09:22 AM
Yeah, it's only a metre away. So not really worried about interferance. Just getting enough signal to the amp is my concern.

light-o-matic
04-23-2012, 02:14 PM
Well, ok.. you have three options.

1) You can just plug the computer directly into the 1/4 inch inputs on the amp.. probably with an 1/8 inch stereo Male to dual RCA Male cable.. plus two RCA Female to 1/4 inch male adapters.

This actually works fine a lot of the time.. if you're just doing this for fun, it's worth a shot.

But when it doesn't work.. sometimes it is because you don't get enough level.. or sometimes you get buzzing noise from the laptop power supply.

So then you need to use:

2) An active balancing box.. like the ART Cleanbox or CleanboxPro. This boosts the level.. and balances the signal. But, it doesn't transformer isolate. So, you could still wind up with a noise problem in certain situations.

Or..

3) A transformer (passive) balancing box.. like the ART DTI. This does nothing to boost the level, but it balances and isolates the signal. If your laptop has enough drive level (likely), then this is the best solution . I own two of the ART DTI boxes.. they are pretty decent for $65 and definitely gives me peace of mind when I am trying to connect my equipment to the clubs equipment or trying to connect equipment that is getting power from one generator to equipment getting power from another generator.. or trying to eliminate hum from a laptop to a mixer... If you really take your sound seriously and don't mind spending the money, the Whirlwind ISO-2 does the same thing, for double the price.. but it's a higher quality (better sound, harder to break) unit.

So in short..

Option 1 is the cheap solution.. it usually works.. but when it doesn't it's a real bummer.
If you don't get enough level with option 1, go with option 2.
If you have enough level but are worried about buzz/noise, use option 3.

From a pro perspective, 3 is the best choice because of all the problems you don't want to have, a huge buzz in your audio is one of the worst.