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  1. #1
    Crank it up, dude! huh? hydroman's Avatar
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    Unhappy Need an Amp for 15" Sub

    Oh Snap!

    The NAD amp powering the new 15" sub is blowing internal fuses and is (i suspect) DOA. I need another amp in the 500W to 1000W class to power the sub and cost ~$100.

    The amp is 20 years old and the caps have failed before. I isloated the caps from the circuits and it still blows the fuse - just not as violently. So i suspect secondary damage as well. The speaker is fine - no damage and it didn't fail internally and overdrive the amp.
    The failure occured during a huge bass signal demand (We Were Soldiers Once... during mortar attack! I just figured a frag got it )


    I am thinking Ebay or craigs list/used. I am thinking i don't need a class A - it is a sub so sound clarity signal/noise etc. isn't as important. It just needs to bridge mono.

    So - suggestions? It could even be ugly/hidden.
    H/K AVR635 7.1
    Denon DVD900
    AE AEGIS III Mains
    ION USB Turntable w/ Shure M97XE
    15" Titanic III Sealed Enclosure Sub
    Dayton Rackmount 1000W :O
    Denon Surrounds
    Sony Bravia KDL40S2000

  2. #2
    Forum Regular audio amateur's Avatar
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    I don't suspect you'd find class A for a hundred bucks in a long time.

  3. #3
    Crank it up, dude! huh? hydroman's Avatar
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    No kidding.

    That is why i am loooking for another possible avenue.

  4. #4
    Suspended markw's Avatar
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    you're gonna need a bigger boat.

    That 2200 is a pretty beefy amp, but all amps have their limits.

    What's the impedance of that sub? Are you running the 2200 in bridged mode?

    Is that titanic a powered sub?

    If push comes to shove, up your budget ald consider one of these:

    http://www.americanmusical.com/Item--i-BEH-EP2500-LIST
    Last edited by markw; 02-27-2008 at 11:02 AM.

  5. #5
    Shostakovich fan Feanor's Avatar
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    Makes so much sense

    Quote Originally Posted by markw
    ....

    If push comes to shove, up your budget ald consider one of these:

    http://www.americanmusical.com/Item--i-BEH-EP2500-LIST
    2400 watts into 4 ohms, bridged. That will handle the 15" sub for sure.

    I recommended the same amp today to a member who wanted to drive Bose 901's at a high school reunion.

  6. #6
    Crank it up, dude! huh? hydroman's Avatar
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    Good input!
    I did a search and found some rack amps for PA (like the link) but they also had the RCA inputs i needed. Very encouraging!

    Yes the Titanic is unpowered and the NAD was bridged mono.

    The titanic is 4ohm.
    Power handling: 800 watts RMS/1,100 watts max
    Impedance: 4 ohms
    Fs: 19.93
    Xmax 20.5 mm
    Sensitivity: 91.7 dB 2.83V/1m
    Vas: 7.79 cu. ft.
    Qts: .38

  7. #7
    Suspended markw's Avatar
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    A few tips on bridging an amp

    Quote Originally Posted by hydroman
    Good input!
    I did a search and found some rack amps for PA (like the link) but they also had the RCA inputs i needed. Very encouraging!

    Yes the Titanic is unpowered and the NAD was bridged mono.

    The titanic is 4ohm.
    Power handling: 800 watts RMS/1,100 watts max
    Impedance: 4 ohms
    Fs: 19.93
    Xmax 20.5 mm
    Sensitivity: 91.7 dB 2.83V/1m
    Vas: 7.79 cu. ft.
    Qts: .38
    first and foremost, when you bridge an amp, it "sees" the speaker load as one half it's rated impedance.

    That means you were essentially driving, at best, a two ohm load.

    Now, the NAD may be rated down to two ohms under normal circumstances, but when you try to push near-sub-sonics through it at extremely high levels, strange things can happen. Add to that that the 4 ohm rating is most lilkely a nominal rating, which means it can dip even lower at times, it's highly likely that you brung it to it's knees.

  8. #8
    Shostakovich fan Feanor's Avatar
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    Good point

    Quote Originally Posted by markw
    first and foremost, when you bridge an amp, it "sees" the speaker load as one half it's rated impedance.

    That means you were essentially driving, at best, a two ohm load.

    Now, the NAD may be rated down to two ohms under normal circumstances, but when you try to push near-sub-sonics through it at extremely high levels, strange things can happen. Add to that that the 4 ohm rating is most lilkely a nominal rating, which means it can dip even lower at times, it's highly likely that you brung it to it's knees.
    It is unlikely that the NAD is rated for 4 ohms bridged which could be the whole problem here.

    An amp like the Behringer EP2500 is rated for 4 ohms bridged, (2400 watts, mono). You'll notice that is also explicitly rated for 2 ohms stereo. Beware: many but not all pro, (PA), amps are rated for 2 ohms stereo / 4 ohms bridged.

  9. #9
    Crank it up, dude! huh? hydroman's Avatar
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    I knew i was asking the right people!

    Using that criteria i refined my search and found this:
    http://salestores.com/pypz19ramo20.html

    So? Should i pull the trigger?
    Thanks for any guidance!
    H/K AVR635 7.1
    Denon DVD900
    AE AEGIS III Mains
    ION USB Turntable w/ Shure M97XE
    15" Titanic III Sealed Enclosure Sub
    Dayton Rackmount 1000W :O
    Denon Surrounds
    Sony Bravia KDL40S2000

  10. #10
    Suspended markw's Avatar
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    "Stereo or Bridged Power Into 4 Or 8 Ohms"

    Well. the blurb does contain those "magic" words and seems to have all the power you ever need but I've learned tnat most times if something seems too good to be true. it usually is.

    What, exactly, do those words mean? Think carefully. It's not what you think.
    (hint: Note the careful placement of the word "or" in both halves of the sentence)

    Also, I'm very curious as to how they arrive at that "2000 watts" figure. Not all amps are rated the same way and not all "watts" are equal.

    Go to this link and download the manual for this unit. Read carefully the specs page. Along with the power ratings, something else doesn't jive between what the advertisment vaguely implies and what the specs clearly state on page 6 under speaker impedance.

    http://www.retrevo.com/search/v2/jsp...q=Pyle+PZR1000

    Generally, I'd believe the specs page over an advertisment.

    After all is said and done, this unit might put out 440 "real" watts in to an eight ohm speaker in bridged mode. It won't do four ohms in bridged mode.
    Last edited by markw; 02-29-2008 at 06:18 AM.

  11. #11
    Shostakovich fan Feanor's Avatar
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    Won't do 4 ohms bridged

    Quote Originally Posted by markw
    Well. the blurb does contain those "magic" words and seems to have all the power you ever need but I've learned tnat most times if something seems too good to be true. it usually is.

    What, exactly, do those words mean? Think carefully. It's not what you think.
    (hint: Note the careful placement of the word "or" in both halves of the sentence)
    ....

    Go to this link and download the manual for this unit. Read carefully the specs page. Along with the power ratings, something else doesn't jive between what the advertisment vaguely implies and what the specs clearly state on page 6 under speaker impedance.

    http://www.retrevo.com/search/v2/jsp...q=Pyle+PZR1000

    ...
    Are the 901's 8 ohms or 4 ohms? If 4 ohms then I wouldn't trust this Pyle model to do the job. Read the specs above: you will note the "bridged" specifications are for 8 ohms only.

    As I implied before, if an amplifier will do bridged into a 4 ohm speaker, it will says so explicitly; also it will provide a 2 ohm stereo specifications. This is because, as markw said, the bridged amp "sees" half the speaker's impedance, hence a 4 ohm speaker = 2 ohms to a bridged amp.

  12. #12
    Crank it up, dude! huh? hydroman's Avatar
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    Aaaaah! Good catch! Thanks a million for the link and the tip. Nope - it cannot bridge mono to my 4ohm load.

    So. What are my options at this point?

    Find an amp stable to 2ohms/bridged mono

    Build/buy another speaker (to run in series giving an 8ohm load)

    Sell the Titanic and buy an 8ohm driver

    ? Any other option?

    Thanks! This thread has been very useful - just saved me $160 and another smoked amp!!

  13. #13
    Suspended markw's Avatar
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    Quote Originally Posted by Hydroman
    So. What are my options at this point?

    Find an amp stable to 2ohms/bridged mono?
    You've answered your own question. Another sub would require another enclosure and, even then, you'll still need an amp.

    Sometimes, our wants and our budget don't mesh properly. You just aren't gonna find the kind of power you want for much less than that Behringer. They do make a slightly less powerful version, but it's only $50 less.

    In your case, you may want to either back off on your watt demands, up your budget, or save up for what you really need. Remember,that NAD 2200 was a well built, fairly beefy amp and you managed to suck that dry. You aren't gonna find any better for the budget you've allocated to this venture.

    My advice would be to save up for the EP2500 or look for a used one on Ebay.

  14. #14
    Shostakovich fan Feanor's Avatar
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    Opps, sorry, hydroman

    Quote Originally Posted by Feanor
    Are the 901's 8 ohms or 4 ohms?
    ....
    Your the guy with the sub, not the 901's

    In any case you get the picture.

  15. #15
    Crank it up, dude! huh? hydroman's Avatar
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    Yeah, i will go back to The Sub Committee for Budget and Finance and recalama the original budget authorization based on new information.
    H/K AVR635 7.1
    Denon DVD900
    AE AEGIS III Mains
    ION USB Turntable w/ Shure M97XE
    15" Titanic III Sealed Enclosure Sub
    Dayton Rackmount 1000W :O
    Denon Surrounds
    Sony Bravia KDL40S2000

  16. #16
    Crank it up, dude! huh? hydroman's Avatar
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    Woot!

    I recieved approval for the Dayton HPS1000watt rack mount amp http://www.partsexpress.com/pe/showd...number=300-810

    On its way!

    Rock on!

    I really liked the beefy design and sound shaping flexability. Great warranty.

    I liked the Crown (i got to see one in action at my church) but the cooling fan was noisy & always on. The Behringer sounded like the same issue and was harder to find. So for a few more $$ the Dayton was the clear winner.
    H/K AVR635 7.1
    Denon DVD900
    AE AEGIS III Mains
    ION USB Turntable w/ Shure M97XE
    15" Titanic III Sealed Enclosure Sub
    Dayton Rackmount 1000W :O
    Denon Surrounds
    Sony Bravia KDL40S2000

  17. #17
    Shostakovich fan Feanor's Avatar
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    Should work really well

    Quote Originally Posted by hydroman
    Woot!

    I recieved approval for the Dayton HPS1000watt rack mount amp http://www.partsexpress.com/pe/showd...number=300-810

    On its way!

    Rock on!

    I really liked the beefy design and sound shaping flexability. Great warranty.

    I liked the Crown (i got to see one in action at my church) but the cooling fan was noisy & always on. The Behringer sounded like the same issue and was harder to find. So for a few more $$ the Dayton was the clear winner.
    Congrats, hydroman.

    The Dayton should work really well. The EQ is potentially very useful, not to mention the integrated low-pass.

  18. #18
    Crank it up, dude! huh? hydroman's Avatar
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    ^true dat!

    I discovered that the sub wasn't sealed well - so i RTV'd it and it sounds much better.

    Also, i had packed too much insulation (Lightly they said! Lightly pack it.) and after removing almost half of it - is louder and far better defined.

    I am still playing /tweaking the EQ, but now having a clip light helps keep me out of trouble...

    Grins.
    H/K AVR635 7.1
    Denon DVD900
    AE AEGIS III Mains
    ION USB Turntable w/ Shure M97XE
    15" Titanic III Sealed Enclosure Sub
    Dayton Rackmount 1000W :O
    Denon Surrounds
    Sony Bravia KDL40S2000

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