2. amps-preamps
  3. 143557-20253

How to DIY yourself very nice Class D monoblocks

If you want to know what the hoopla is about Class D and want to put together a very nice sounding kit I have a starter recommendation for you.

Go to Parts Express and search for "ICEPower ASP"
Next, look online for Ghent Audio. They make many sets of cases.

You'll need a high power soldering iron, and screw skills.
Between those two, you can put together a very nice monoblock for around $500 a piece.

I highly recommend both. I have no financial interest in either. 
You may need wiring kits, so make sure to order appropriately.
erik_squires
erik_squires OP
16,898 posts
 
What are you guys doing to get around the low input impedance of the ASP modules? I think it’s around 7-8K ohms. My preamp’s output impedance is 200 ohms. That's not good, right?

Hi @Ketchup,
200 should be fine!! It's usually recommended that there be a 10:1 ratio, so you'd have more than enough.

Best,
E


georgehifi's avatar
georgehifi
10,312 posts
 
I think it’s around 7-8K ohms. My preamp’s output impedance is 200 ohms. That’s not good, right?
Your good with that, but these amp manufacturers that insist on inputs that low need to be beaten around the head, as no passives or most tube actives will drive these silly low input impedance’s.
There was a sort of unspoken standard for a while which was 47kohm or higher. I think 100kohm should be made the standard.
Hell Rogue Audio on most of their poweramps are 1megohm!!!

Cheers George
ketchup
702 posts
 
Thanks, george and erik.
Let's say you wanted to build two mono amps with NC400 modules, but you wanted to put two NC400 modules in each mono chassis so one would drive the bass panel and the other would drive the midrange/tweeter.  Is it possible to split the input at the mono amp so the signal goes to both NC400 modules?  Are there any possible downsides in doing so?
erik_squires OP
16,898 posts
 
Hi @ketchup
Not really, but the impedance would drop to 4k.

Most solid state pre amps would have no issues with this at all, but some tube may.

However, maybe what you really want to do is active biamp? Hypex sells active crossover modules as well.

Best,
E
ketchup
702 posts
 
I’m not really interested in active biamping yet. I just learned that the NC400 modules are bridgeable, so it’s possible to use two modules per channel and have double the power. Would the input impedance of two bridged modules also have an input impedance of 4k ohms?
More to discover