Class-D as a bassamp

[XXLPeanut]

Hello all.
What do you all think of using the setup on page 17 of this datasheet.
amp

Im building a poweramp for my bassguitar and have allready made a slightly modified version of the albert kreuzer preamp.
Do you think this is suited for what I want.
In the datasheet I see that they recomment it as a subwoffer amp, but I cant really make out a frequenzy range.. A bass has freq. from app. 30hz to 10khz. This might be a problem for a sub-amp.
Thanks.

[sovadk]

It looks like it has a cutoff frequency of 80kHz, so it can reproduce the whole audio spectrum. Taking it's high THD into consideration, it might be best suited for bass applications.

[XXLPeanut]

Originally posted by sovadk
Taking it's high THD into consideration, it might be best suited for bass applications.

Hello.
I dont have much experience on the class-D area, but I see your point. 0,3% @ 10W seems like a lot. As a reference my marantz Pm7000 has 0,03%. Im not sure at which power though.
Does somebody have an idea where to go, if I want a smaller THD. Perhaps a complete design for a 50-200W amp. Ideally I'd like to bridge similar amps if I need more power.
Thanks in advance

[BWRX]

http://www.41hz.com/

Check out the amp2 kit. I've only had good experience buying kits from Jan so far.

[XXLPeanut]

Originally posted by BWRX
http://www.41hz.com/

Check out the amp2 kit. I've only had good experience buying kits from Jan so far.

Thanks.
This looks very interesting.
Do you think it will work well as a bassamp?
On the forum at 41hz.com i see some people having problems with their amps.. Anyone else have an oppinion on the amp2?
What about the cap update they mention.. will that only be neccesary if I want more power or would it enhance performance as it is...
Thanks Nikolaj

[Qwnzmostwanted]

I have a marantz pm7000 im pushing two 15s 500w each i have the mode on processor with the bass and treble up after about half way it will sound so horiable is this because the speaker cant hadle more or is it because it doesent have enough power to give. i think it doesent have enough power because it does that to every singe speaker i have. Is there any way u can bridge this amp for more power?? if theres a way please let me no.

[classd4sure]

Look at the Hypex modules, www.hypex.nl

Very solide, robust, strong performance, and extremely easy to work with. The sound is also above reproach, you can't go wrong with them. Modules are already assembled. They're for full range but will do fine for bass only.

[raintalk]

Key to bass amp use is a good power supply.
Bass frequencies consume the most power, and you'll need a good power supply to keep up. The good news is class-d is much more efficient so you won't be wasting power supply capacity on heat.

You'll hate yourself unless you look for SMPS - lightweight, big power supplies can be heavy. I don't know of too many available for DIY's but there's some here:
http://www.digiamps.com/products.html

[Eva]

In that kind of class D circuits featuring pre-filter feedback, most of the distortion comes from a lack of linearity of the tiny ferrite output inductors employed and from excess flux leakage being picked up by small signal stuff. Those undersized inductors intended for SMPS suffer both from core hysteresis at low current levels and from saturation at high current levels, granting plenty of odd harmonics. Of course, that's absolutely fine for boom boxes and 5.1 multimedia systems.

We always blame power supplies when we don't understand further in the chain.

[Pierre]

I have also built a bass amplifier basing on a coldamp module.

www.coldamp.com

My experience is very good so far: I first bought 2 of them for a full-range setup about three months ago. Very easy to set-up, very robust due to their excellent mechanics, reliable, lots of features, excellent sound (I also have 2 for a full-range amp), and GREAT documentation and technical support (thanks, Sergio!).

Then I purchased another two modules a week or so ago for subwoofer application. They told me that the new units have bigger mosfets (44A ones), and that they can handle 2 ohm easily, so I tested with a big 4 ohm PA subwoofer in bridge mode, outputting more than 1KW power with only two modules.
You don't even need an external heatsink other than screwing the module to the base.

I am now waiting for their SMPS to become available to feed this monster! Seems quite a bit more oversized in terms of storage capacity, etc, as compared to digiamps'

I will have to ask for a couple of free modules due to the "advertising" Just joking, I just wanted to share my positive experience with these guys, as everybody is doing here.