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Emile

overdriven amplifier

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OK; know the general consensus is to get an amp rated at 2x the "continuous pink noise" level rating of the speakers. So, "know" an amp will possibly "clip" if played towards max volumes and it can hurt the speakers as they may "sit" on the clipped wave.  But; really do not fully understand it ... can I just avoid clipping by keeping the volume at reasonable levels???

 

Now for my "personal" history.  Have always had under-powered amps :(  Ran my KPT-904's (600W ???) with a Marantz 2252B (52wpc) and they were LOUD and excellent sounding ... never heard any clipping even when almost turned to max volume. (OK; switched to a Crown K1 with about 400wpc and the bass is "tighter.")

Next I'm getting a pair of JBL bass bins (model SR4718A; 600W, 4ohms). Hoping to match these with my extra set of K-510/K-691 horns (on a separate amp, using DSP) ... tried to match the horns with Forte's, but they completely overpower them :( Yes; if the sound is "good," I'll buy a "bigger" amp (looking at a Crown XLS 2502; 775W at 4 ohms) ... but want to try them first with my spare Marantz 1060 (30wpc; prob about 45wpc at 4 ohms).  Could I "safely" try this at say 1/3rd or 2/3rds power??  Do not want to blow the woofers as replacements are $300-500 each :( 

 

Many thanks!

 

Cheers, Emile

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It looks like you have quality amps with good clean power, and capable of dropping down to low ohms. I think clipping occurs most when an amp can't handle the low ohm dips of a speaker.

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39 minutes ago, Emile said:

Marantz 2252B (52wpc)

If that receiver is up to spec...

 

it should bench in @ 58-62....

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6 minutes ago, Ceptorman said:

It looks like you have quality amps with good clean power, and capable of dropping down to low ohms

Thanks! Haha ... if I'm lucky you just saved me $500 ... check is in the mail :D Per my SPL calculator ( http://myhometheater.homestead.com/splcalculator.html ) I should be able to get 118dB's form these (corner) JBL's :) 

Cheers, Emile

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  If you go with one of the XLS models I have two suggestions.

1. Drive it from a balanced source. Many comment about issues with normal efficiency speakers and hum or noise. The amp generates some strong fields in the back of the amplifier. Some RCA cables pick it up. 

2.Terminate the speaker cables with Speakon connectors. The EU binding posts are the worst.

  With a balanced source and Speakon connectors the amps are nice sounding. Everyone one who had negative comments on sound quality used RCA cables and the binding posts. 

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1 hour ago, Panelhead said:

I have two suggestions

Awesome suggestions ... Thanks :D 

Add-on ... Have a Crown K1 ... used RCA's and had some noise ... switched to "pseudo" balanced; RCA from pre-amp to XLR's into the Crown and the noise was gone :D  Can't explain it, but it helped :D 

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OK; got the JBL 18" bass bins (SR4718A, 600W) in the house. Wife is not impressed by the looks :( Hooked them up to my pre-amp (JVC P3030) then via miniDSP 2x4 (35-920Hz) and into a Marantz 1060 (30wpc, but guess about 45wpc on 4 ohms).  With the Marantz 1060 at close to full volume I do NOT get much sound ... rough guess is 85-90dB's :(  (Additional complication is that I cannot turn my pre-amp to full power - only about 1/3rd - as it makes the miniDSP clip.)  Any suggestions?

Thanks, Emile

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Hey Emile,

You need one, or 2 of these...

https://www.avhub.com.au/news/hi-fi/world8217s-most-powerful-amp-at-ces-395109

 

With all due respect, you have got to stop looking at those MAX wattage numbers on the specs of your speakers

(especially the Pro models that you are rightfully enamoured with).

This just is not a concern in "most" home situations, maybe different in a 600 seat auditorium  where your 904s would normally be.

"Have always had under-powered amps :(  Ran my KPT-904's (600W ???) with a Marantz 2252B (52wpc)"

 

Claude has tried to illustrate just how much power is required to make "our" high efficient speakers sing, not a ton of power is really needed.

As Paul said...

"What this world needs is a good 5 watt amp." - Paul Klipsch

 

 

 

 

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INMHO you can never have enough clean power, especially one with a large torrid transformer with large  power reserves.  Your volume control should take care of over-driving the speakers, if your ears last that long.

 

Regards,

John 

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There is a  really nice pre and amp posted just earlier by a famous builder...Garage Sale. Enjoy!

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16 hours ago, HPower said:

You need one, or 2 of these...

https://www.avhub.com.au/news/hi-fi/world8217s-most-powerful-amp-at-ces-395109

 

With all due respect, you have got to stop looking at those MAX wattage numbers

Haha ... 900 wpc into 8 ohms ...  just do NOT like the connectors up front :D Plus can easily get over 1000 wpc with bridged Crown amps :) 

alt

 

OK; seriously ... NO; not really concerned with Watts speaker rating ... all my stuff has always been "underpowered."  Reason for the above post was that I was surprised (disappointed?) that I did NOT get any volume out of these 18" JBL (4 ohm, 98dB, 30-3300Hz) woofers with my Marantz 1060 (guessing 45 wpc at 4 ohms).  Never had woofers this big and was just wondering if they indeed needed some serious power. OK, will be doing some more experimenting :D 

 

Thanks, Emile

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13 minutes ago, Emile said:

Haha ... 900 wpc into 8 ohms ...  just do NOT like the connectors up front

 

I think that is a picture of the back panel. 

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Ya, that is the back.

This Boulder requires some fancy 32 amp connector and dedicated circuit from your fuse box.

 

I am not sure what type of enclosure your 18s are in, but bass does require more power and JBLs are traditionally less efficient than heritage Klipsch.

 

The Boulder was a joke 😉, I can't imagine anybody on this forum needing this kind of power.

SET amps are not everybody, but I have run both Cornscalas and Klipschorns with 45 SET (1.8-2wpc) and 2A3 SET (3.5-4wpc) and never felt

I was "underpowering" my speakers.

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15 minutes ago, HPower said:

I am not sure what type of enclosure your 18s are in, but bass does require more power and JBLs are traditionally less efficient

It's a ported enclosure ... but specs say 98dB's for these SR4718A's, so "thought" I could power it with say 50wpc ... guess that's not going to work :( 

JBL 18 passive sub pair

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3 minutes ago, Emile said:

It's a ported enclosure ... but specs say 98dB's for these SR4718A's, so "thought" I could power it with say 50wpc ... guess that's not going to work :( 

JBL 18 passive sub pair

I would use them upside down with the K510 horn crossed at 500 Hz. The chip amp should work fine.

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11 minutes ago, ClaudeJ1 said:

The chip amp should work fine.

Whoopie :D 

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On 3/12/2019 at 5:50 PM, Emile said:

Awesome suggestions ... Thanks :D 

Add-on ... Have a Crown K1 ... used RCA's and had some noise ... switched to "pseudo" balanced; RCA from pre-amp to XLR's into the Crown and the noise was gone :D  Can't explain it, but it helped :D 

It CAN be explained. It involves science and electrical engineering:)

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2 hours ago, Emile said:

Haha ... 900 wpc into 8 ohms ...  just do NOT like the connectors up front :D Plus can easily get over 1000 wpc with bridged Crown amps :) 

Yea but the power from a Boulder will be real true RMS continuous power, not make believe peak program music watts. And you WILL pay for it.

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The ONLY speakers I have ever damaged were all 4 of my subwoofer drivers by sending them TOO MUCH POWER for too long and I melted 4 voice coils.  I sent ~400 watts to each when they were rated at.350 watts.  I was using my SPL meter to be safe and heard no distortion.  With the enormous amps you have, a bad cable or a needle drop will push a woofer onto to your carpet, or light the cones on fire.  You have no need for all that in a home.  If you can't hear any strain or brittleness you are not clipping enough to hurt anything.  your pro gear is tougher than consumer gear with 2 watt tweeters that are the source of the clipping horror stories. 

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