hi!!!!!!!!!!!!!!!!!!!!!!!!!!!!!,

i just wanted to know if rythmik audio plate amps ( the 350 watt non-servo one) are 2 ohms stable? i don't know if anyone has tried it yet. i did a search and really didn't find too much.

also, a few months ago, i was plannin on buyin a MAW 12" from mach5 audio. i had a box designed for it which came out to 5 cu ft. and 2 ports about 17" inches long ( i think) for a dual tuning of 18 and 26Hz. i wanted to know what other subs can i put in this box in case i buy the sub and hate it??

as a matter of fact, what 12" subs are available that i can use that can be put in any size enclosure ( doesn't just have to be the 5 cu ft one) with dual tunings? it'll be powered by a rythmik audio amp of course and it'll be for 80% music and 20% movies? thanks

You put a lot more info here that you did with your PM over at ICIX.

The only plate amp that I think is 2 ohm stabe was from Adire and was well over $1,000.

As for subs, most that I listed in my reply (ED, TC, Etc) will all work but will have very different responses.

-Robert

You put a lot more info here that you did with your PM over at ICIX.

The only plate amp that I think is 2 ohm stabe was from Adire and was well over $1,000.

As for subs, most that I listed in my reply (ED, TC, Etc) will all work but will have very different responses.

-Robert
well, that's because :p
and i was lookin at that new tcsounds sub and the dayton dvc. i think they're really good choices. i'm really shootin for that dual tuning though. when i had my tempest, it was in a 7.25 cu ft box tuned to 18Hz. it was okay for music and really great for movies. i know i can get the best of both worlds if HSU and SVS can do it

i'm using the mach5 MAW-12 with the rythmik 250, wired series for 8 ohm load.

I've got it in ~4.5 ft^3 (136.6L) tuned to ~17.2 hz.

~110dB@20Hz in room.

pics in the construction thread and gallery, search on chaise lounge to find it.

thanks. anybody else?

Just email Rythmik and ask. I know I've emailed the dude there and he has responded.

I'm running one of the 350 non-servo amps on an old school Kicker 18" (4ohm)

http://www2.breakbeatmilitia.com:8090/gallery/listpics.asp?dir=Subwoofer

Yes, Brian would certainly be the best person to ask. Or, you could just look at their online manual (http://www.rythmikaudio.com/manual/A350_basic.pdf), and see that it says:
This subwoofer amplifier is NOT recommended for sealed box speakers with DC voice coil resistance of less than 2.5 ohm, nor for vented box (passive radiator) speakers with DC voice coil resistance of less than 3.0 ohm.

i just got this today:

brian,
i've been snooping around on a coupla forums and couldn't find any answers. i wanted to know know if the 350 watt non servo as well as the servo plate amp you guys have are 2-ohms stable? if they are stable, how much power could we expect from them? i was talking to this 1 guy a few years ago and he told me that they are stable, but he had a small fan that blew directly on the heatsink too so it wouldn't get too hot.

brian responded= It will be stable, that is, no oscillation. But you can only drive it half the max output to avoid overheat. Overall, I don't recommend that. Imagine this, for half the load, you almost got twice the power. The power does not come for free. It must have violated some design constraint. (underlines are mine)


can anybody explain the underline part?

i just got this today:

brian,
i've been snooping around on a coupla forums and couldn't find any answers. i wanted to know know if the 350 watt non servo as well as the servo plate amp you guys have are 2-ohms stable? if they are stable, how much power could we expect from them? i was talking to this 1 guy a few years ago and he told me that they are stable, but he had a small fan that blew directly on the heatsink too so it wouldn't get too hot.

brian responded= It will be stable, that is, no oscillation. But you can only drive it half the max output to avoid overheat. Overall, I don't recommend that. Imagine this, for half the load, you almost got twice the power. The power does not come for free. It must have violated some design constraint. (underlines are mine)


can anybody explain the underline part?

Ok...

V=IR
Voltage = Current(amps) * Resistance(ohms)

So basically a lower resistance means alot more current can flow.

anyone else?

He's simply saying that due to the higher current of running at low resistance, the amp is going to run much hotter. Heat is current driven more than power driven. Running at 2 ohms will result in twice the current than the same power at 4 ohms. Therefore, you won't be able to drive the amp to full power, due to the heat issue. It's not designed to be a high current amp, and trying to use it as such is a compromise.

Running at 2 ohms will result in twice the current than the same power at 4 ohms.

Incorrect.

V=I*R
and
P=I*I*R=V*I

If you're running 100W into 4 Ohms, you will have a current of 5 Amps, at 20V. If you're running 100W into 2 Ohms, you will have a current of just over 7 Amps, at 14V.

The issue is the internal impedance of the drive transistors. Their losses are also described by I*I*R (with R being the internal impedance of the semiconductor junction), so the heat generated by the transistors will double when you halve the speaker load impedance.

Yes, you are correct, of course. :)