200W Amp Rushjob

[pinkmouse]

Hi folks.

Help required. An old friend has called in a favour, and I need to build him an amp in a week or so. However, it's not so daunting as it sounds. I have a rackmount case, heatsinks, two 39-0-39 300 VA traffos and psu boards in my bits pile, so physical construction won't take long, just a case of bolting everything into the enclosure. What I do need is a good solid basic amp schematic using MJ15003/4 or MJ21193/4 outputs, with easily available components, and preferably PCB layouts I can copy myself. Best option so far looks to be the SC300 from Silicon Chip magazine, but I'm open to other suggestions.

SQ isn't paramount, but as I will probably get this back in six months or so it would be nice to get something reasonably good, possibly with the option to upgrade so I can use it to drive my AVC 15 based sub project that's in the pipeline.

Thanks in advance.

[pinkmouse]

Pic of the bits so far.

[Stuart Easson]

Al,

Why don't you build the ksa50 with higher rails but keep the idle current down to a sensible level...

with 39v ac, you are probably going to need to bridge the amps to get 200w RMS, the ksa50 with 2 or 3 x mj15003/4 is pretty good for that sort of stuff...

Stuart

[pinkmouse]

Doh!

How many Krell boards do I have sitting around here? Talk about Wood/Tree interface situation!

Good idea. I should have mentioned that this will be for 4Ohm loads, so the rail voltage shouldn't be a problem. What are your experiences with the higher rails? Should I go CCS?

[EUVL]

JLH Class A.
You don't even need PCB. Just point to point on Vero boards.
Check out Geoff Moss's website.

(PS Won't meet 200W requirement, but amp sounds wonderful.)


Patrick

[pinkmouse]

Problem is, Patrick, it needs to be 200W and I don't have the heatsinks for Class A!

[anatech]

Hi Al,
Just build them stock if you have the boards. They sound good and you can play with them when you get it back. But at least you will get them up and running. Use the better cap types and resistor types for now and you will be close to there.

-Chris

[Zen Mod]

if not crippled Krell,then go to ESP site and look for his subwoofer amp;
decent,what I can say else?

[pinkmouse]

I looked at that Choky, but because of the rush I didn't want to get into designing and prototyping a pcb, (or waiting for delivery of Rod's premade PCBs). If I went that way, I'd be fussing with it for months.

Chris, it's even simpler than that, I already have prototype boards built from the project. I might just have to replace a few caps with higher voltage ones, and reinstall the trannies I took out. The reason I asked Stuart about using the CCS is that he has had some experience with cranking up the rails, and I seem to remember above a certain voltage he recommended using one.

[forr]

quoted
---JLH Class A.....sounds wonderful.---

I never found an answer to a simple question : what is its output impedance ?