So just where is the preamp?

Discussion in 'Eversolo DMP-A10' started by Bob Harris, Jan 21, 2025.

  1. Bob Harris

    Bob Harris Member

    No guys I’m not meaning so much physically but that is interesting. I mean where is it in the flow of information? The signal path.

    Just received our A-10 this week. Two thumbs up, this is a nice thing to have. Very impressive in many ways, but I have a confusion.

    Today I got a 20 foot usb cable for the Umik-1 microphone and did a Room correction. It did fix a boominess I’ve noticed but that’s not my point here.

    I’m intent to use the streamer and DAC aspects of this gizmo, but would pass the signal to my McIntosh C8 tube preamp, their baby model.

    I’ve always considered any signal manipulation even balance control much less eq or room correction to be the duty of the preamp. So here’s my question: Where’s the “preamp” of the A10 in the signal path? Is it possible to bypass all that and go direct to my outboard preamp and still use the room correction?
     
  2. barza

    barza Member

  3. barza

    barza Member

    Copied the block diagram from another post - hope it helps.

    According to eversolo tech support the PEQ and room correction are also passed to the USB digital output even though that is not shown the above diagram.

    So I guess you tell the A10 unit to give you full line level on the analog outputs, connect to your preamp, and you can have all the PEQ/Room correction on anything you feed into or comes from the A10.
     
  4. j2j

    j2j Member

    I connect A10 through XLR to BAL CD of Accuphase E-5000. The sound can be controlled both by A10 and Accuphase E-5000. I don’t know is this answer your question 0r not.
     
  5. Bob Harris

    Bob Harris Member

    I believe you are on track to my dilema. I’m using the A-10 much like a preamp. It passes per XLR to the McIntosh C8 tube preamp. Pretty little thing that matches my baby Mac MC 830s. Beautiful things, remind me of a new Bentley, nice to have in the room.

    I’d sure like to utilize the tube amplification of the Mac but am using the room correction of the A10. Just yesterday began using the volume control on the A-10 instead of the Mac, neccessary in order to sync with the new subwoofer. And like you, volume controls on both function.

    Here’s the dilema. Seems we have duplication of functions and circuitry. I’m essentially running two preamps in series. That sure seems undesirable on the surface, but how to resolve? Immediate answer is to mothball the Mac Tube preamp, which is not an ideal solution for me

    Maybe this is just fine, but sure feels odd.
     
  6. Bob Harris

    Bob Harris Member

    Here’s the question: am I getting any advantage of the tubes for amplifying the signal for the power amps?
     
  7. barza

    barza Member

    Given that you want both the sub control and the room control from the A10, and the tube harmonics/distortion from the pre amp, I don’t think you can avoid the duplication. If you were prepared to deal with the subs without the A10 you could just use it for the room correction and have it give line level out and then your tube preamp would control the volume. As for the tubes giving you an advantage, the question is whether they colour the sound (or just look good in your room) in a way you find pleasing.

    In an ideal world you would isolate the audio only part of this by doing a proper blind level-matched A/B/X test with the tube preamp being switched in and out of the single chain. But setting that up might be a complete pain. You could try and do a unscientific version of the A/B/X- have someone either hook up or not the tube amp in a way you can’t see, level match as best as one can, and then see when you listen if you can identify when the tubes are in the path and when they are not. But even that would only deal with the audio part, not the “Bentley” aspect. You might find you can’t reliably tell when the tube preamp is being used, but still want to use it because it is a lovely piece of electronics and you enjoy looking at it as part of your system. Nothing wrong with that!
     
    Last edited: Jan 26, 2025
  8. Bob Harris

    Bob Harris Member

    Thank you for your response.

    So here is the next question. Is it even possible to bypass the preamp function/circuitry of the A10? Or are you constrained to use it no matter what? Seems like the transport can be used independently, the DAC also. But the preamp circuits are going along for the ride no matter what.

    Feels like we have run into my level of ignorance. Is this “preamp section” very significant as far as potentials for distortion, or just too insignificant to have any concern over?
     
  9. barza

    barza Member

    My understanding is that the pre-amp section of the A10 is very high quality and unlikely to color the sound very much at all. Of course at this point you are handling analogue (as opposed to digital) signal and you would want that signal as hot as possible going into your tube amp without distortion. My guess is that you would be able to get to a point where the influence of the A10 pre-amp in your system was imperceptible with a bit of a trail and error of the output line level from the A10.
     
  10. Purité Audio

    Purité Audio Well-Known Member

    The analogue is completely transparent Mirror mentioned once I believe a sinad of -128dB.
    As good as it gets in other words.
    Keith
     
  11. ColtrColtrane63

    ColtrColtrane63 New Member

    We should be here to decide whether to improve the audio reproduction, I think a test without preamp should be done, or did you discard it due to incompatibility of impedances, sensitivity, gain?
     
  12. Purité Audio

    Purité Audio Well-Known Member

    You can’t improve upon audibly transparent, you can however make it worse if you add a component with audible distortion.
    Keith
     
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  13. Bob Harris

    Bob Harris Member

    Now that we have determined that running the preamp functions of A10 and the C8 preamp in line won’t cause one to erupt in a fireball, I’ve been free to play with dual volume controls.

    This is grest. The fancy illuminated volume knob of the A10 controls the whole system including the subs. Meanwhile the very nice ultra smooth knob on the McIntosh C8 controls the baby monoblocks and hence the Blades. This gives me a super easy way to balance the output of the subs to the main speakers, outside the app.

    And I can quickly mute the main speakers and reveal to the world exactly what part the sub is playing. Can switch main in and out and really “see” what you’re getting.
     
  14. ColtrColtrane63

    ColtrColtrane63 New Member

    Be careful though, it is not easy to manage two potentiometers, in two different points in series with the signal, remember that the one on the preamp will be used to manage the volume you want to listen to, while the one on the Eversolo, in this case, will have a narrow range of action, if too low it will be influenced by worsening the signal to noise ratio, if too high it can saturate the input signal to the preamp, to put it simply, there is a point, difficult to discover by ear, where the signal that arrives at the preamp is better, good work.
     
  15. Purité Audio

    Purité Audio Well-Known Member

    Can’t imagine why you would even consider two preamps.
    Keith
     
  16. Bob Harris

    Bob Harris Member

    Right that just feels wrong. It was not the plan. Have enjoyed the McIntosh tube preamp for a couple of years. Plan was to bypass the Eversolo preamp section but it’s not like you can really separate it out. That’s the point of this thread.

    But, since I’ve been corraled into using two in line preamps I’ve seized on some advantages. Having a volume control that does not effect the subs is handy for tuning it all by ear. Probably not used often or very much. Still using the Eversolo as the primary volume control.

    And yes it sure feels like this setup has to introduce distortions, but is it audible?
     
  17. Audiobill

    Audiobill Member

    You may want to turn the passthrough on the Eversolo "on"to bypass its volume control.

    Also, look at the reviews on. Stereophile and Audio Scence Review for the Eversolo DMP-A8. I'd expect the analog stage of the A10 to be at least as good.
     

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