My new space heater

[MEGA-amp]

SOZ

My first amplifier ever!!! (built a BrianGT GC, not full DIY). Absolutely unbelievable!! Yes i'm running it single ended, and its only one channel but............WOW.

details:
1500VA 38V
392000 total uF
2 parallel 2.2mH inductors per rail
Irfp244
final rail 49V

[MEGA-amp]

apparently the coils are just too small. I initially had them in series, but they got way too hot. Now they seem to be doing fine.

[MEGA-amp]

on/off switch?? Thats my elegant soft start cut-out, I get a whole half an amp with the thermistors out of the loop. Need that precious current!!

[MEGA-amp]

Since I first found these pages, I had to build it, its just way too cool. Much appreciation to Nelson Pass, and the many great people on this forum!! Now on to the other channel, which will put my Aleph2 on hold for another millenium; right now its just a big paper weight. Whatever, right now im listening to pure magic, through one channel!!! TOTALLY AWESOME

John

[wayne325]

I think you need to get some fans going on that baby.
Maybe 1500 fps with a 12" exhaust would do the trick.
Or, how about water cooling. You could route it right
to radiators and heat your house.

[MEGA-amp]

It takes about an hour or so for the big sink to get close to unbearable, but its sitting atop my desk with no airflow. I think with a proper chassis it should be alright. We will certainly see. In my initial parts quest I looked at these water cooledresistors. Probably would heat my 12x12 room a little quicker with a fan and a radiator.


John

[moe29]

Didn't you just love drilling and tapping all those holes for the power
resistors? that's my fondest memory of building the SOZ

Now you should really consider building a BZLS, so that you can run
the SOZ balanced. I think you will find it worth the effort. Plus you'll
have a great preamp to run your other projects.

[MEGA-amp]

Didn't you just love drilling and tapping all those holes for the power resistors? that's my fondest memory of building the SOZ

Well...... I cheated a little. The sinks had predrilled holes in it, and they just happened to be the right size. I initially wanted to mount the resistors with a little symmetry, but in the end, one screw with a few tiny washers turned out to be enough. With enough force they will move, but its solid and they make good contact. I was one of the lucky ones to get Kari's X-BOSOZ boards, eventually it will be driven properly. One question: With the Soz and my Aleph 2 cooking, I smell bi-amp. Will the X-Bosoz drive 2 amps at once, or do I need seperate preamps for each amp. I'm fairly new at this and still soaking it all in, but wouldnt driving two amps lower the output impedance of the preamp? I guess i'm equating it to an amp going from an 8r load to a 4r load. Not sure if im correct here.

John

[metalman]

You're thoughts on biamping are more-or-less correct, but the X-BoSoZ has more than enough output drive to handle a SOZ and an Aleph2 simultaneously.

[MEGA-amp]

Well thats a relief, thanks metalman. As it is, the sound of the SOZ makes my spine tingle, even though its playing through a commercial bookshelf speaker. My previous experience with what I thought was hi-fi or least mid-fi was a Pioneer sx-1280. At close to 40 watts output for the Soz, it blows the pioneer away. It seems to have more control of the speaker. 1500VA may be a bit small, possibly, but it doesnt hum nor is there any heat generated by the trafo. I can only imagine with an Aleph 2 added to the mix; its sure gonna get the feet tapping.


the guinea pig: