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Thread: not all high current amps are equal

  1. #1
    Registered User MJC's Avatar
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    not all high current amps are equal

    We all know, generally speaking, that separates will produce a better soundstage, and overall sound, than integrated amps and both are better than receivers.

    But my first thoughs of the difference, in db output, between a high current 85w amp(receiver) and a high current 100w amp would be about the same, as far as where the volume controls were set playing the same source, thru the same speakers in the same room.
    I couldn't have been more wrong. Using a Denon 85w receiver, most lps were played with the volume at -10 ~ -7db, with half speed master recordings at -3 ~ 0db.

    With the Citation 11 pre-amp/Citation 19 100w power amp I'm only around -18 ~ -12db, and that is peak, for the same half speed masters. Those numbers are according to the LED db meters. And that is producing around 85db at the seated position 9 ft away. Talk about having plenty of headroom to spare! And ya, the soundstage and overall sound is much improved.

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    Hello
    The position/db scale of the master volume control verses how loud the system is or when the amp reaches it's peak does not in it self tell anything about the amps output or headroom. An amplifier with a higher input sensitivity ( say 1.5 volt for max rated output) will require more input from a preamp to produce the same output as an amp with a lower input sensitivity ( say .75 volts for max rated output). You can't really judge an amps power or headroom by were the volume control is at.

    Mike Caldwell

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    Dis Member mikebake's Avatar
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    Quote Originally Posted by Mike Caldwell View Post
    Hello
    You can't really judge an amps power or headroom by were the volume control is at.

    Mike Caldwell
    THANK...........YOU.............................

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    Senior Member jim campbell's Avatar
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    Quote Originally Posted by Mike Caldwell View Post
    You can't really judge an amps power or headroom by were the volume control is at.

    Mike Caldwell
    my audio research pre has a 10 db cut switch on the back to facilitate more flexibility of the volume control.ive also heard tha more than a few lower priced receivers have most of their gain between 0 and 50% of the dial as to increase the wow factor in the showroom

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    Registered User MJC's Avatar
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    Well if a receiver's digital volume control is at 0db there isn't going to be much head room left. The rated max output is at 0db. Of coarse, peaks will be higher.
    The point is, in this case, the rated outputs between the two amps is only a difference of 15w. So that would suggest that the receiver's 85w is over rated, where as the 100w amp would seem to be under rated.
    When the volume @ the seated position is the same (measured with a spl meter) and one unit is at 0db and the other is around -24db, that's a big difference for two units that are suppose to be only 15w difference.

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    Administrator Robh3606's Avatar
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    When the volume @ the seated position is the same (measured with a spl meter) and one unit is at 0db and the other is around -24db, that's a big difference for two units that are suppose to be only 15w difference.
    For the speakers to have the same SPL output you need the same power output from each of the amps. So they are putting out the the same power for the the different volume control settings. Could be that 0db may have something to to with setting levels for a 0db reference point for HT. Did you check the owners manual on the reciever. For 85 db average your only going to be using 10 watts or so. That leaves both amps with almost the same headroom.

    Rob

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    Registered User MJC's Avatar
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    Unhappy

    Quote Originally Posted by Robh3606 View Post
    For the speakers to have the same SPL output you need the same power output from each of the amps. So they are putting out the the same power for the the different volume control settings. Could be that 0db may have something to to with setting levels for a 0db reference point for HT. Did you check the owners manual on the reciever. For 85 db average your only going to be using 10 watts or so. That leaves both amps with almost the same headroom.

    Rob
    This is a stereo setup and the Denon receiver was new last year, thus it has a digital volume control.
    The Citation 11 pre-amp/19 power amp are '70's vintage, have no markings of any kind on the volume control. But the Citation 19 does have LED lights for each channel. When the sensitivity 1 button is set, the top pair of red LEDs represents 100w. When the 2 button is set the same pair of LED represents 5w.
    When the spl meter, at the seated position, reads 80~85db, while playing a half speed master lp the red pair of lights are only being lit occasionnally during peaks, with the "2" button set. That's only 5w peak.
    To get the same 85db from the Denon the volume control has to be at 0db, that's 85w. Or so I would think.

  8. #8
    Senior Member Ian Mackenzie's Avatar
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    I am not surprised you can hear a difference.

    Take the lid of and compare the transformers and PS capacitors.

    Also the Denon may not have the same output stage or front end PSSR

    Basically it comes down to the design.

    The number of stages, usually more in something like a Denon leads to a loss of transient capacity and stability.

  9. #9
    clmrt
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    What is the exact list of equipment for both systems?

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    Registered User MJC's Avatar
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    Quote Originally Posted by clmrt View Post
    What is the exact list of equipment for both systems?
    It not two systems, it only one. I bought the Denon receiver last summer to drive the L890s. Then I bought the PS PT800s for the ht. Thus 5 of the L212s got put into two other rooms. My two mirror imaged, Couple-Charged L212s replaced the L890s where I had the turntable. My daughter is now the proud owner of the L890s.
    I came to the conclusion that the Denon wasn't any where near the quality I wanted for that pair of L212s. So I got the Citation 11 pre-amp and the Citation 19 power amp.
    The Citation 19 is by far much heavier than any of the 3 receivers I have, and maybe as heavy as the Parasound 5 channel amp. The Denon receiver weights almost nothing. The soundstage that the Citation provides is far superior to the Denon and maybe anything else in this house.

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    Sounds like the Citation has a mag phono input and the Denon doesn't...

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    Registered User MJC's Avatar
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    Quote Originally Posted by moldyoldy View Post
    Sounds like the Citation has a mag phono input and the Denon doesn't...
    They both have phono inputs. I just downloaded the Citation manual and compared it to the Denon manual. Both input impedances are 47k ohms, but the input sensitivitys are different, 1.5mv for the Citation, and 2.5mv for the Denon.

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    And the cartridge output is...? at what impedance...?

    For any system to achieve rated gain, the input level must meet/exceed the following stage's input sensitivity, and a magnetic phono cartridge offers the lowest output of any (consumer) device of all. Also note that a mag phono input sensitivity is usually considerably lower than one simply tagged 'phono'.

    At these very low levels, oxidized connections or excessive cable length can really wreak havoc too, and moreso than higher level devices.

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    Registered User MJC's Avatar
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    Wink

    Quote Originally Posted by moldyoldy View Post
    And the cartridge output is...? at what impedance...?
    You are taking it way past what it is. The facts are that the Denon does not have the chops of the Citation 11 pre-amp/19 power amp. Which is why I bought the Citation combo and put the Denon in the closet.

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