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  1. #1
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    What should I hear (different) when in Passive Mode?

    My limited understanding of Passive mode is that the sound does not go through the majority of circuitry but mainly just through the volume controls.

    Why does one want to use Passive mode; when the source electronics is better than the Pre Amp?

    I have only used this a few times when trying to get a better grip on the volume steps for lower level listening. I have yet to do any extended listening or comparison to normal gain mode.

  2. #2
    Vinyl Fundamentalist Forums Moderator poppachubby's Avatar
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    Extended listening is the only way to decide what you like. Yes, passive mode will be more direct.

  3. #3
    Silence of the spam Site Moderator Geoffcin's Avatar
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    Quote Originally Posted by Hyfi
    My limited understanding of Passive mode is that the sound does not go through the majority of circuitry but mainly just through the volume controls.

    Why does one want to use Passive mode; when the source electronics is better than the Pre Amp?

    I have only used this a few times when trying to get a better grip on the volume steps for lower level listening. I have yet to do any extended listening or comparison to normal gain mode.
    I use a passive pre in my setup. The idea is that if you don't need gain from your preamp then you should have no need to send the signal through all that circuitry. Basically in passive mode the preamp acts as a switch box with an attenuator. It's the closest you can get to a straight wire. It funny, but back in my days of chasing the "straight-wire-with-gain" ethos I could actually hear the difference in the resistors in the volume control! (the preamp uses an expensive multi-resistor unit with silver contacts) In full open mode none of the signal was sent through a resistor and it sounded better to me.

    Technically nothing should be closer to a pure signal than a passive preamp. In actual use though many recordings will sound better with powered preamp for any number of reasons from impedance matching with the amp, to the added bass impact that a powered preamp usually adds to the mix.
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  4. #4
    Phila combat zone JoeE SP9's Avatar
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    Ideally a passive setup may sound better. That's part of the less is more school. I've heard some complaints of a loss of dynamics when using a passive preamp. Try if for yourself. You've got nothing to loose and maybe some knowledge to gain.
    ARC SP9 MKIII, VPI HW19, Rega RB300
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  5. #5
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    So I have had the Pre in Passive for a few days now. It's hard to get the volume and drive up to where the tube gain goes but I have noticed a few things. I still have to find time to crank it a bit louder.

    What I have noticed is
    A- Lower level listening is enjoyable since I can get a good full sound and soundstage without high volume

    B- The sound is a bit more laid back as opposed to closer to in your face but it is very full

    C- I can get it to a reasonable volume with great detail but still be able to have a conversation

    D- Lacking bass at lower volume but the bass is accurate (even with sub)

    I'm gonna spend more time with it in passive and attempt to get to louder volumes for comparison to normal gain mode.

  6. #6
    Silence of the spam Site Moderator Geoffcin's Avatar
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    Quote Originally Posted by Hyfi
    So I have had the Pre in Passive for a few days now. It's hard to get the volume and drive up to where the tube gain goes but I have noticed a few things. I still have to find time to crank it a bit louder.

    What I have noticed is
    A- Lower level listening is enjoyable since I can get a good full sound and soundstage without high volume

    B- The sound is a bit more laid back as opposed to closer to in your face but it is very full

    C- I can get it to a reasonable volume with great detail but still be able to have a conversation

    D- Lacking bass at lower volume but the bass is accurate (even with sub)

    I'm gonna spend more time with it in passive and attempt to get to louder volumes for comparison to normal gain mode.
    One of the deciding factors when I purchased my Arcam Alpha 9 CD player (besides the fact that it blew everthing this side of a $10K Meridian player away) was that it had a greater than nominal output of 2.5v. I never needed additional gain when using the CD player.
    Audio;
    Ming Da MC34-AB 75wpc
    PS Audio Classic 250. 500wpc into 4 ohms.
    PS Audio 4.5 preamp,
    Marantz 6170 TT Shure M97e cart.
    Arcam Alpha 9 CD.- 24 bit dCS Ring DAC.
    Magnepan 3.6r speakers Oak/black,

  7. #7
    Sophisticated Red Neck manlystanley's Avatar
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    Great discussion! I was debating if I wanted to get a passive pre or not. But seeing that my Jamo's are laid back to start with, as passive Pre would not be good.

    Best Regards,
    Stan
    Listening/Movie Room: ADCOM GTP-500, XPA-2, Denon 3930ci, Front: Jamo C809; Surround: Klipsch R-5650-S; Back: R-5650-S; Denon AVR-687,. Projector: Sharp XR-32X.

    Family Room: Denon avr-687, Denon CD player, Klipsch RB-5II

  8. #8
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    Quote Originally Posted by manlystanley
    Great discussion! I was debating if I wanted to get a passive pre or not. But seeing that my Jamo's are laid back to start with, as passive Pre would not be good.

    Best Regards,
    Stan
    Hey maybe-maybe not. It will all depend on the pre and source. Right now I am using my SS Stratos amp. I still have to switch back to the Counterpoint Hybrid for further analysis.

  9. #9
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by Hyfi
    Why does one want to use Passive mode?
    As others have indicated, you get higher resolution and in some cases, a wider soundstage due to minimizing crosstalk. I use that approach in the main music system. While I have a preamp, it is used for vinyl only. There are three criteria for determining whether or not a system is suited for passive operation:

    1. Sufficient gain. Most high level sources today produce 2 or more volts output with a majority of power amps requiring no more than that for full gain. Sometimes, however, you'll find recordings that require more gain than expected. My CDP has an unusually high gain (4 volts) which provides 6 db more gain. I can clip my amps with virtually any recording.

    2. Proper impedance matching. One always needs a low impedance driving a higher impedance. Opinions vary as to the optimum ratio, but most agree that at least 10:1 works fine. I use 10k attenuators with a 70 ohm output source driving a 137k load which provides at least a 13:1 ratio. Since the rate varies with the level of attenuation, the figure gets a bit better in practice. At -6db (a common setting for me), the ratio goes up to 27:1. Many solid state amps, however, are not good candidates because they tend to have very low input impedance such as 10k. Your Stratos appears to be 22k which may not be optimum.

    3. High frequency roll off due to cable capacitance. Here is where you need short, low capacitance cabling. DACT offers a calculator on their website to provide attenuation curves. Using generic red and white or Monster cables with high capacitance will likely roll the top a bit. My total cable capacitance is 160 uF, so roll off begins above 100 kHz.

    Because of all the variables, you will find mixed results using different systems. And there are some folks who prefer the added "fullness" and "brightness" afforded by adding another gain stage. Very high resolution systems do not sound impressive at first blush. It is only after extended listening and hearing deeper into the recording that you find added detail that did not exist before.

    Good luck with your experiment.

    rw

  10. #10
    Charm Thai™
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    I had the opportunity of driving my system with a Mac MCD500 (up to 6v output) and bypassing the preamp. In the end I preferred the sound with the preamp, maybe due to the tubes, so it's really system dependent and whatever your ears agree with.

  11. #11
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by shodulik
    In the end I preferred the sound with the preamp, maybe due to the tubes, so it's really system dependent and whatever your ears agree with.
    I think it is more likely that your SS amplifier was responsible. It has the low 10k input impedance I mentioned when using single ended cabling (and only 20k when balanced).

    rw

  12. #12
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    Quote Originally Posted by E-Stat

    2. Proper impedance matching. One always needs a low impedance driving a higher impedance. Opinions vary as to the optimum ratio, but most agree that at least 10:1 works fine. I use 10k attenuators with a 70 ohm output source driving a 137k load which provides at least a 13:1 ratio. Since the rate varies with the level of attenuation, the figure gets a bit better in practice. At -6db (a common setting for me), the ratio goes up to 27:1. Many solid state amps, however, are not good candidates because they tend to have very low input impedance such as 10k. Your Stratos appears to be 22k which may not be optimum.
    Thanks for all this great info.

    I got very nice results last night when I flipped on my JM Labs Tantal 509s via Niles box and 50ft of zip cord also running off the Stratos. Very impressive sound for no tube gain.

    I can't find the specs for my Counterpoint online but do have the manual and will check them. I'll also be swapping it back into the mix shortly for some more listening.

  13. #13
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by Hyfi
    I can't find the specs for my Counterpoint online but do have the manual and will check them. I'll also be swapping it back into the mix shortly for some more listening.
    I've found a reference which suggests that it is 100k ohm like its lower output version. Which makes it more passive friendly.

    Specs

    Little brother

    rw

  14. #14
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    I am continuing to enjoy my system in Passive mode for several reasons. I still use the Low Gain mode when just playing music loud to hear throughout the house or a selected disk, and also when I use my HT which drives the mains as fronts through the VAC.

    But for normal sitting down listening, I am starting to prefer the Passive mode. I have much more control of the volume at lower levels for one thing. It also sounds more natural and not so in-your-face as with the gain.

    It does work out much better with the Counterpoint and Clearfields than it did with the Stratos and Danes due to the impedance and synergy.

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