*Comparison and Review* Magni/Modi vs O2/ODAC - Page 18

Quote:

Originally Posted by Jason Stoddard 

It's simply the quiescent current in the output stage--in the case of Magni, about 30mA--hardly enough to really get warm. P= IV, where I is .03 and V is 30V--so it dissipates about 2W at idle from 2 channels. I forgot the actual FLIR numbers, but it runs something like 27C in a 20C room.

Don't forget the regulators.

After a 30 minute warmup (and measuring immediately after removing the top cover), the regulator cases were running around 140F (60C) and the output devices around 150F (66C). That's enough to make the top cover feel warm, but certainly not hot.

Top cover with Magni off was 72F. After idling for about 30 minutes, it rose to about 84F. Warm to the touch, but not even body temperature. So no reason for anybody to fret.

Oh yeah, while you're here, my Magni has a problem. Whenever I turn the knob all the way to the left, I get no sound. What's up with that? Can I get a new one?

Have a great weekend, Jason!

se

Yeah, I've heard of that problem. About 99.8% of the Magnis have it, unfortunately. I've heard it's a relatively common problem with other amps.

Despite that, we'll put our entire engineering team on it and see if we can develop a fix. I believe Dave (our DSP and microcontroller wizard) could probably work up a PIC-based control system that would, say, allow you to get full volume at the touch of a button even with the pot fully to the left. Of course, that may not be the best solution, unless you want a special "destroy my headphones" function.

(Actually, the first preamp I designed for Sumo had the pot wired backwards on the prototype PCBs. So, in that case, you'd have plenty of output at full left, especially with 20dB gain and +/-35V rails. Hello, voice coils.)

I'll send it on down. Wait'll you experience the alternate reality it produces.

se

Doesn't that happen with most amplifiers? Maybe not...my lack of experience is getting to me isn't it? XD

I always thought the volume knob is supposed to go from volume 0 to volume max.

You see Steve...what you have started.....there is always someone that will take the bait....I actually rewired my volume pot with heavier gauge wire and the volume is back to normal....wonder if that will make the specs and better now between the ground and center tap?

Guess I'll just get the Schiit since it's cheaper 

Gotta hand it to Schiit, these boxes look great!

One thing bothers me about the OP's [awesome] review: the O2 and Standalone ODAC are not meant to be stacked, as they're a cabling disaster this way. The real O2+ODAC combo has a far more orderly appearance since it's assembled in a single box. I've only skimmed through these 18 pages--hope this hasn't already been pointed this out.

Stacked or not, you still get a mess of cables in the front.