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JBL 705P / 708P

Discussion in 'Speakers and Room Acoustics' started by watchnerd, Jan 28, 2017.

  1. 12B4A

    12B4A Member

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    It seems like they didn't go with an all-one-chip for the amplification part. There are 6 chips on the signal side of the board that have heat sinks, 2 are FREDs (FCU20A40) and 4 are switching FETs (IRFR4615).
     
  2. Blumlein 88

    Blumlein 88 Major Contributor

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    You fellows keep on with the positive reports and I may end up wanting some of these as they become readily available.
     
  3. Palladium

    Palladium Member

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    *looks at the LSR305s right in front of me*

    What blatant lies. All of us know multibillion audio companies can't design good products especially Harman who sold themselves out to Samsung.
     
  4. watchnerd

    watchnerd Major Contributor Beer Hero

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    I'm thinking the 708P would pair nicely with the NAD M12.

    Choose XLR or AES inputs, or maybe go wireless with Blue OS modules.

    If only it had a headphone jack.
     
  5. 12B4A

    12B4A Member

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    Sooo...the Class D amp section consists of an IRS20957S (one for high, one for low) driving the IRFR4615 FETs. The necessary Coil/Cap combos on the outputs are sized uniquely for HF or LF.
     
    Last edited: Aug 13, 2017
  6. watchnerd

    watchnerd Major Contributor Beer Hero

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    Price: ~$8 in single quantities

    LOL at Class A amps.
     
  7. Palladium

    Palladium Member

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    But-but-but if we use that taboo Class D garbage how would we be able to stand listening to unmusical amp distortion produced magnitudes well below the transducers own distortion?
     
  8. Blumlein 88

    Blumlein 88 Major Contributor

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    The NAD M12 would be a good combination. However initially I have an old Tact unit that is a digital pre-amp. And it has AES/EBU outs. So I could feed that right in and have a workable all digital setup with remote and multiple switchable inputs.
     
  9. Blumlein 88

    Blumlein 88 Major Contributor

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    Easy you'll need an audiophile modification to add an external LPS to each Class D chip.
     
  10. watchnerd

    watchnerd Major Contributor Beer Hero

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    Not to mention the SMPS...
     
  11. watchnerd

    watchnerd Major Contributor Beer Hero

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    https://www.sbooster.com/
     
  12. Thomas savage

    Thomas savage Moderator Moderator The Watchman

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    I'm of the thinking , if you know the load ( speaker) and you are the one pairing the known drivers with the known amp ( your making a active speaker) then there's no need to spend much on the amplification.

    If your making a amp to deal with a whole host of unknown loads ( speakers , drivers , xovers ect) this is a different and frankly far more expensive and inefficient thing and more costly. ... and really just wrong nowadays imo.

    I'm all for brilliant waveguides and fantastic drivers with perfectly matched amp modules and the digital signal processing to make all work in a optimal way, oh then you can test it as a system so have more control over everything.

    No brainer ..

    I'm fairly excited to get my hands on the 705p's , knowing they match the quality of the big M2 if not the horsepower obviously.

    It means I can set them up and directly compare the music to what I expirence though my current home audio system. It's my hope that over the next few years I will end up with a simplified system based on the logical/scientifically valid engineering of the 7 series.
     
  13. Palladium

    Palladium Member

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    If the audio solution makes too much sense, it will be derided by the 'phools.

    Besides Class D amps + SMPS + DSP is like their unholy trinity of audio blasphemy right there. And those $1000 power cords per speaker ain't cheap you know.
     
  14. jtwrace

    jtwrace Member

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    As an M2 owner and Harman visiter, I can say they will blow you away. Being able to go through the LSR, 705p, 708p and M2's blind was a scary experience. The 705p and 708p are no joke!

    http://www.audiocircle.com/index.php?topic=149780.0
     
  15. watchnerd

    watchnerd Major Contributor Beer Hero

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    I was wrong. The M12 doesn't offer variable volume control on the digital out, only on the analog side.

    So I'm still in search of an ADC with variable volume and a remote (if I want to go the digital input route).
     
  16. Thomas savage

    Thomas savage Moderator Moderator The Watchman

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    It does do volume attenuation in the digital domain ( 35 bit ) though, it's a shame if that's not offered though the digital out, reading about it seem a really great implementation.
     
  17. 12B4A

    12B4A Member

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    After rooting through the guts, I'm now thoroughly convinced that given the level of processing sophistication, build quality, parts costs, and drivers used, the powered 7 series line is a really high value return on the dollar. When you start to guesstimate labor (even when the amp/dsp is a made in Vietnam amp-in-a-hotel-pan design and the speaker is assembled in mexico), packaging, marketing, shipping, and engineering costs, it makes one wonder how thin the margins are. It seems like these are aggressively priced to push out Genelecs, Focals, Neumanns, Dynaudios, etc. from pro studios.

    It also seems like a no-brainer for JBL to just drop this same amp/dsp module in to the M2 cabinet with no real drawback in performance besides 6-7dB less output.
     
  18. dallasjustice

    dallasjustice Addicted to Fun and Learning

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    If Dirac ever releases Unison, these JBL speakers would be the ideal match for ideal bass management since they are full range and relatively small. I bet it would only take 4-6 of these to fully implement Unison with minimal accompanying hardware.
     
  19. 12B4A

    12B4A Member

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    That's exactly why I've been holding off on doing any upgrading to any kind of pre/pro. I want to see which products end up with a Unison implementation.
     
  20. dallasjustice

    dallasjustice Addicted to Fun and Learning

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    Whenever Dirac releases Unison, I think it will change a lot of things. I use a similar approach with opposing out of phase subs to control length modes. There is no comparable other bass management technique or room treatment. If it's implemented, it will be a fundamental shift in home audio, IMO.
     
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