Amp Internals 2

Hopefully the pictures work now.

Pop the lid (which is actually the bottom panel) and we get this:

Close-up of the caps. I didn't switch it on to test rail voltages, but given the output power ratings, I'd expect them to be running in the 190-200V DC range.

Next up, I put my phone into the gap at the top left corner of the first picture, and took a picture pointing towards the front of the amp:

Bit of heatsink in the distance - I suspect that runs the whole way across.

At the PSU section (the bit that isn't covered), we've got some smaller grey caps:

With a scary-high voltage rating. Wouldn't want to touch those terminals.

Finally, the output inductors:

If you charge all the big caps fully, you've got 580J of energy storage (an MA5002VZ has 363J), although that only tells part of the story - it's also important to know how often they're charged from the power supply. A really big capacitor bank charged up once per second might fare worse than a small capacitor bank that's being charged up 1000 times per second.

It would be interesting to take the panel off the PSU section, but I'm afraid there are too many screws in awkward places - I'd have to start removing PCBs, and I don't fancy doing that on an amp as expensive as this.

Chris

Yeah, from what I've heard the MAi and Itech lines are very similar.

I got this amp for a great deal because the seller didn't have the correct power cable, so they hadn't tested it. They still offered a warranty, though, so all I had to do was find a cable to get it up and running.

As you'd expect from Crown, it worked perfectly and ran my subs for a few years. I moved across to Powersoft T-series and lost a little power, but the functionality and rack space was worth it.

Chris

I got brave and went a little further. Getting to the output devices was just a matter of removing the output inductors. Couple of screws and some big spade terminals, and off they come.

There are four banks of output devices in total.

The one I checked had these:

4x IRFB20N50K

2x ISL9R3060P2

I don't know a lot about circuit design, and even less about high-frequency switch-mode stuff.

If anyone has any clues about whether those parts are good/bad/indifferent, it'd be an interesting read.

Chris

Speakerpower Sp2-12000