Sub Plate Amp

[ChrisR1983]

Yo

I'm after buying a plate amp for a sub I'm going to build.

My room is pretty small and I plan on using it to drive a 10-12" sub. I don't listen to music particularly loudly because my Mrs is "sensitive" to loud volumes

I'm in the UK - who sells fairly cheap plate amps over here? I could get one from parts express but the carriage is the same price as the amp!

Looking at about 50w - is that ridiculously low? What wattage would you guys use for a room about 3mx4m?

Thanks

Chris

 

[Mario Pankov]

Europe Audio offers a few options, these will be withoutimport duties for you and shipping is from the Netherlands, so it should be cheap. The DPD option is fast and reliable, so do not over pay for UPS.

 

[ChrisR1983]

Yea they have a 120W plate amp by Hypex but its pretty expensive compared to the $80 at parts express

Any other cheapo options?

 

[chris661]

Here's an idea

Buy a 12V DC power supply, then get a car amplifier - those things are cheap, and the power supply is around £50.

POWERCOOL|PC750AUBA|PSU, 750W 80+ DUAL 12V V2.2, POWERCOOL | CPC is the PSU - very handy. The cheapest one is around £40, but does 450W

 

[leadbelly]

Have you considered NOT using a plate amp? IMHO those things are horribly overrated, especially if you have to locate it far away from your system since the line level signal will pick up a lot of hum. I'm actually rebuilding my plate amp now so that it will sit on my rack. Why don't you go buy an old 100W/ch stereo amp at a thrift store and use that?

 

[davygrvy]

...especially if you have to locate it far away from your system since the line level signal will pick up a lot of hum.

One word: transformer

 

[leadbelly]

One word: transformer

Yeah, thanks for the hot tip on the more elaborate, expensive, and less elegant solution to the problem.

 

[ChrisR1983]

If I use a 100W/channel amp I will have to build a seperate crossover/filter. A lot of plate amps seem to have a variable cut-off

What do you guys do in terms of a crossover for the sub?

 

[leadbelly]

If I use a 100W/channel amp I will have to build a seperate crossover/filter. A lot of plate amps seem to have a variable cut-off
What do you guys do in terms of a crossover for the sub?

Oh, if you're system is stereo, then yes a plate amp is a very handy all-in-one solution. For an HT system, I just use the crossover in the surround receiver.

There are standalone sub crossovers out there, like this one: Creative Sound - Product Details and:
Creative Sound - Product Details

Anyway, my point was that I hate plate amps, and so if you are only looking at plate amps and these have an inflated landed price in the UK, then look outside the box to see what's available locally.

EDIT: Sorry, wrong product links: http://creativesound.ca/details.php?model=F-1

 

[Mario Pankov]

The thread got interesting Has anyone tried to use a class D car amp, something that can pump out about 350W? You can find such for 150-200 euro and it will be much powerful than a plate amp which has a ridiculous price, all you might need will be a transformer.

 

[mattmcl]

Honestly, I didn't use a crossover when I built my first sub. I can't remember what they are called, but I got these coils, they look like a 5 inch wide inductor, that block all but the bass. They were very cheap and easy to install.

 

[Jacques Merde]

If I use a 100W/channel amp I will have to build a seperate crossover/filter. A lot of plate amps seem to have a variable cut-off

What do you guys do in terms of a crossover for the sub?

I think you will find a separate crossover a significantly more satisfactory solution than the variable frequency low pass filter built into the plate amp.

I snagged a used one off eBay for about $50 US a while back. Another solution is one of Rod Elliott's kits.

 

[Colin]

This UK company does plate amps. They have a good reputation and make a range of amplifiers and subs. Their amps have appeared in well-reviewed subs from Ruark and rega.

Home Page for quality UK manufactured subwoofers and sub bass systems

 

[TheSeekerr]

Honestly, I didn't use a crossover when I built my first sub. I can't remember what they are called, but I got these coils, they look like a 5 inch wide inductor, that block all but the bass. They were very cheap and easy to install.

Said coils are indeed inductors. By installing them in series you form a first order lowpass filter. The trouble with doing it this way is that the slope of the rolloff is very shallow, so the sub will still be playing a significant amount of non-bass content.

The other problem is that to start the rolloff at, say, 100hz, you need quite a large inductor, something on the order of 13mH. High quality inductors of this size are quite expensive.

At the end of the day, it's a solution which can work, but is far from optimal.

Just putting this out there for any future new fella's who think they don't need a crossover - the series inductor is a crossover, just not a very good one.