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Thread: Is a 30-50 watt Tube Amplifier enough power for the 4350 HF section?

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    Is a 30-50 watt Tube Amplifier enough power for the 4350 HF section?

    Title says it all.

    Is 30-50 watts enough to power the HF section of the 4350. On paper given the sensitivity of the HF section, 99db/w, you would think so. However I have found even though JBL's can be highly efficient they like power too.

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    Senior Member turnitdown's Avatar
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    99dB with one watt and you have 30-50 watts? The math ought to answer your question.

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    Quote Originally Posted by turnitdown View Post
    99dB with one watt and you have 30-50 watts? The math ought to answer your question.
    I don't believe its that simple. The LF section is 96db/w, based on the math 50 watts should be enough for that too. I guarantee its not.

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    Administrator Mr. Widget's Avatar
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    For most people it is probably all you would ever need, but it won't satisfy everyone.


    Widget

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    Senior Member BMWCCA's Avatar
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    The brochure for the 4345 suggests for head-room demands a 100w max power would convert to using a 200w amp. There is no such notation on the 4350 brochure I peeked at though it has an even more robust HF section than the similar 4345. I'm running a 100-wpc amp on the HF section on my 4345s. I think I'm doing fine at anything close to a normal listening level—to way beyond what the rest of my family is comfortable with!

    Have you tried yours with more power?
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

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    Quote Originally Posted by BMWCCA View Post
    The brochure for the 4345 suggests for head-room demands a 100w max power would convert to using a 200w amp. There is no such notation on the 4350 brochure I peeked at though it has an even more robust HF section than the similar 4345. I'm running a 100-wpc amp on the HF section on my 4345s. I think I'm doing fine at anything close to a normal listening level—to way beyond what the rest of my family is comfortable with!

    Have you tried yours with more power?
    I am currently running the top end with a 300 watt Class A Krell amp. Complete over kill but I don't have anything of comparable quality to power it at the moment. Bottom end is run with a Crown XLS amp but I have a JBL MPA600 here which may replace it.

    I would like to get a tube amp or lower powered Class A SS amp for the HF section. The Krell is going to waste at the moment.

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    Senior Member 1audiohack's Avatar
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    Do you have an oscilloscope?

    I have answered axactly what you are wondering by measuring the peak voltage of the amp output at as high a volume level as I think I would ever play a sound track with wide dynamics.

    Since it is a system you are familliar with and you know the volume position in use, and are using a voltage supply amp you could even disconnect the speakers and measure in silence.

    I have seen peaks of 68 Volts on my 4350’s before, on the 12” driver. Oddly a higher peak voltage requirement than the 15’s.

    Most people that know me will tell you that my definition of loud is different than most.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    Quote Originally Posted by 1audiohack View Post
    Do you have an oscilloscope?

    I have answered axactly what you are wondering by measuring the peak voltage of the amp output at as high a volume level as I think I would ever play a sound track with wide dynamics.

    Since it is a system you are familliar with and you know the volume position in use, and are using a voltage supply amp you could even disconnect the speakers and measure in silence.

    I have seen peaks of 68 Volts on my 4350’s before, on the 12” driver. Oddly a higher peak voltage requirement than the 15’s.

    Most people that know me will tell you that my definition of loud is different than most.

    Barry.
    I dont have a scope nor am I technically capable. I do like to listen loud though, with my SPL meter I can clock peaks of around 105-110db.

    Are you saying the 12" mid-bass is quite hungry and a powerful amplifier is necessary?

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    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by kelossus View Post
    . . . . Are you saying the 12" mid-bass is quite hungry and a powerful amplifier is necessary?
    In music generally there is more energy in that frequency band than even in the bass, and the 2202 can handle it.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Quote Originally Posted by 1audiohack View Post
    Do you have an oscilloscope?

    I have answered axactly what you are wondering by measuring the peak voltage of the amp output at as high a volume level as I think I would ever play a sound track with wide dynamics.

    Since it is a system you are familliar with and you know the volume position in use, and are using a voltage supply amp you could even disconnect the speakers and measure in silence.

    I have seen peaks of 68 Volts on my 4350’s before, on the 12” driver. Oddly a higher peak voltage requirement than the 15’s.

    Most people that know me will tell you that my definition of loud is different than most.

    Barry.

    A further question, 68 volts on the mid-bass. How many watts does that actually equate to? I am complete electronic novice but some quick reading determined I need the current draw to determine watts.

    If my understanding is on point which is not likely as I have no idea, even though the volts are higher on the mid-bass it may not be drawing as much current as the woofers therefore fewer watts.

    Will a high current amp like a Krell KSA50 or KSA80 have enough current to drive the HF section with headroom to spare?

  11. #11
    Senior Member 1audiohack's Avatar
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    Hello;

    The volts to watts calc is simply V squared, divided by Ohms resistance.

    68V squared, divided by 8 Ohms equals 578 Watts.

    These peaks are pretty short in duration but if you want to avoid compression distortion an amp that will swing pretty close to the peak voltage demands is required.

    This is an instance where the “ISBL” If Struck By Lightning amplifier ratings of peak power for a couple of milliseconds actually mean something. Maybe not the best for subs with long duration voltage and current requirements but useful for dynamic music listening.

    I am not advocating for unnecessary gain but I love dynamics. If it doesen’t jump, it doesen’t do it for me.

    All the best.
    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    Good lord peaks of nearly 600 watts. That is insane.

    Based on that I think my current Krell needs to stay on the HF section.

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