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Can the PE 300-794 plate amp be used with a 2 Ohm load?

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5 replies to this topic

#1 of 6 OFFLINE   Javier_Huerta


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Posted December 12 2004 - 01:28 PM

Hi all! I'm building my 4 driver IB. Each subwoofer has a 4 ohm voice coil, and they are DVC's. I can get either a 2 Ohm or 8 Ohm load, and lose almost 100 watts if I went for the 8 Ohm load (from 272 to 180 Watts). Can I use the PE 300-794 in 2 Ohm mode if I add a fan, or if I keep volume levels low? Is it worth it to give it a try? If the amp can't keep up, do you think the amp could be damaged...? I could also try a couple more things, but I'm not sure whether they are good ideas or not... a) Wire one of the voice coils, short circuit the other one on every driver. I'd get a 4 Ohm resistance, but I think I'd lose 3 dB's of output in the process - negating any benefit I'd get from the higher wattage. b) Take a voice coil from each driver, wire them in series and parallel, get a 4 Ohm resistance, and connect this to the 300-794. Then, take the second voice coils, wire them in series and parallel, get a 4 Ohm resistance, and use a second amplifier to drive them. The thing is, the second amplifier would be much smaller (100W @ 4 ohms), and, obviously, a different brand and design. If this could be feasible, then I'd get a very nice 372W output, enough to drive my IB to Xmax. Thanks for your help!
Quid, me anxius sum?

#2 of 6 OFFLINE   Jason Dalton

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Posted December 13 2004 - 03:37 AM

The 300-794 isn't going to work with a 2-ohm load, there have been documented problems running woofers with a DCR under 3 ohms (i.e. Dayton DVC series) with that amp. A two ohm load will certainly cause the thermal protection circuit to cut in on a regular basis. If I were you I would run two woofers for now and save up to get another 300-794.

#3 of 6 OFFLINE   MichaelAngelo


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Posted December 13 2004 - 09:06 AM

I see you live in Mexico City- hotter than Beaumont !! I have 2 of the 300-794 amps running 2 ohms, 1 into each voice coil of an AV-15. Room temmp stays at 68-70F, but I didn't mount the amps to the sub enclosure. I have them mounted in a vertical row, on a standoff fromm the wall. A small fan cools the backside, and another cools the heatsink side. Not the most elegant solution, but it works.
PE expressly warned me against doing this; they've been running strong for about a year and a half, with no problems. On a call to get a friends amp repaired, (ironically, at an 8 ohm load, but sealed in an enclosure) the tech told me its prob pushing close to 380 watts into 2 ohms. Posted Image
However, he told me also that if I fry the amp, it may fry beyond repair, and thus be a total loss.

standard disclaimer applies Posted Image


Just re-read Jasons post-
*If I were you I would run two woofers for now and save up to get another 300-794.*
excellent advice

#4 of 6 OFFLINE   Ryan Schnacke

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Posted December 13 2004 - 11:21 AM

If you've already got this plate amp then why not try hooking it up as an 8ohm load just to see what kind of output you get. With a 4 driver IB your efficiency is going to be pretty good. Maybe you don't need more than 180 watts. There's a couple of reasons that I would not recommend shorting half the coils and running a 4 ohm load. First, if the amp was a perfect voltage amplifier then you would only come out even - 3dB gain from increasing the supplied current and 3dB loss from driving only half of the coils. So you'd be putting extra strain on the amp and the woofer coils for nothing. Second, this amp is not a perfect voltage amplifier. You'll actually get slightly more output running all coils at 8 ohms than running half the coils at 4 ohms. This is because the amp can output 180 watts @ 8 ohms instead of half of the 4 ohm rating (272/2 = 136 watts).

#5 of 6 OFFLINE   HansMe



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Posted December 13 2004 - 10:55 PM

I've got a 300-796 (european from conrad, look for 301044) running 4 8" infinity (kappa400) woofers. It's not running for that long (about a week) already but it's doing fine. It gets hot but not alarming. You've got 4 big woofers. I can imagine the amp getting difficulty at high output...

#6 of 6 OFFLINE   Javier_Huerta


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Posted December 14 2004 - 04:38 AM

Thanks for all your opinions! I definitely think I'll try starting with an 8 Ohm load. I'd love to try 2 Ohms - the problem is, it's very, very difficult for me to get my hands on a 300-794 (it costs me about 2X the amount on PE, and there's no guarantee it'll arrive to Mexico). According to my calculations, each sub has an 88dB / W sensitivity, so 4 subs should give me 94dB / W... I'd guess 180W with very gentle EQ would be more than enough, considering room boundaries and such... Thanks, again, for your help!
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