Rethinking Phono Preamp Gain Settings

Discussion in 'Audio Hardware' started by avanti1960, Jul 8, 2017.

  1. Phil Thien

    Phil Thien Forum Resident

    Location:
    Milwaukee, WI
    Doesn't that Dynavector cartridge work better with a pretty low mass arm?
     
  2. patient_ot

    patient_ot Forum Resident

    Location:
    USA
    It appears to be an old model from many years ago. Western style compliance appears to be 15. That should work okay on a medium mass arm.
     
  3. avanti1960

    avanti1960 Forum Resident Thread Starter

    Location:
    Chicago metro, USA
    good plan. mofi makes decent stuff.
     
  4. avanti1960

    avanti1960 Forum Resident Thread Starter

    Location:
    Chicago metro, USA
    not mine. sutherland gets the noise thing right.
     
  5. Ontheone

    Ontheone Drifting Towards the Dead Wax

    Location:
    Indianapolis
    With SS phono stages you can get extremely low noise for sure. I just happen to be a big fan of the sonics that come with a well-executed tube phono stage and I'm willing to give up a slight amount of dead quiet for the tone that stirs my soul.
     
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  6. nvilletele

    nvilletele Active Member

    Location:
    New City
    I feel that way about guitar amps, so I completely get what you’re saying here.
     
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  7. avanti1960

    avanti1960 Forum Resident Thread Starter

    Location:
    Chicago metro, USA
    agreed, i have tube amplification for that reason. unfortunately for my system a tube phono pre was too much of s good thing.
     
  8. nvilletele

    nvilletele Active Member

    Location:
    New City
    After reading all the many informative posts, here’s where I have come out with respect to the best approach, for me and my situation.

    I am going to first complete setting up my Technics amp in the room with my tt and see how well it might handle the low output DV/Karat, with the current MF V90.

    If not satisfactory, I will return the V90 and get the MoFi StudioPhono and see how its higher output setting does, and whether it has too much noise, etc. The extra $120 cost, plus shipping cost to return the V90 is not significant.

    If the StudioPhono has too much noise at the higher setting, I will get the Piccolo2 and use it along with the MoFi.

    So either way I am only spending an extra 130 or so, and if I need the headamp with the MoFi, I would still have needed it with the V90. And at $250 the Piccolo is not a deal breaker on cost. Both the MF and the MoFi are well regarded low cost preamps, so swapping out one for the other doesn’t seem to be a concern, and the MoFi offers greater flexibility.

    That’s where I am at now (until someone else says something to turn my head again).
     
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  9. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    If I recall that MoFi has a bunch of options. Should work well for you.
     
  10. patient_ot

    patient_ot Forum Resident

    Location:
    USA
    Not talking about noise from phono preamps.
     
  11. Ontheone

    Ontheone Drifting Towards the Dead Wax

    Location:
    Indianapolis
    It's certainly a balancing act between components. I'm happy with the balance that I've struck by using a SS amp, tube linestage, and tube phono stage. Even with 60dB gain coming from my phono stage I have to press my ear to the tweeter to detect any tube rush, even using my 96dB sensitivity speakers. I had to offload a tube amp a couple of years ago to get rid of what I considered a distracting level of noise. By using a Class A SS amp I feel I get much of the essence of a "tube sound" yet with dead quiet.
     
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  12. Ontheone

    Ontheone Drifting Towards the Dead Wax

    Location:
    Indianapolis
    Likewise! I think that's where my love for tubes came from since I was a teenager playing guitar. I still have a Mesa Boogie guitar tube amp circa 1992.
     
  13. clercqie

    clercqie Forum Resident

    Location:
    Belgium
    I've been reading up a bit on noise requirements for phono amps. The noise from the system will be limited by the resistor noise coming from the MC cart. Douglas Self and Burkhard Vogel estimate that around -70db for a 0.2mV output cart (Denon 103). So ideally, the chosen MC phono amp has a noise figure below that limit.

    That said, it seems very hard to see whether or not a MC phono preamp can attain or go below that figure, since reported specs are all over the place; and the noise from the preamp will depend on the chosen gain setting and chosen weighting scheme from the noise measurement... Guess the proof of the eating is in the pudding...



    This thread also goes fast. Lots of new messages, I've not been able to catch up yet.
     
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  14. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    It's interesting to plug the outputs into a computer or such and see where the noise floor sits. I use free plug-ins and AULab on my Mac laptop and with various grounding strategies -72 dB or so is the best I can do.
     
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  15. psulioninks

    psulioninks Forum Resident

    Location:
    Midwest USA
    I think this is largely a case of "can't have your cake and eat it too". High output from a phono stage that is clean and noise-free is expensive. A bit akin to someone looking for "reference" level bass from a speaker but wants to spend less than $500 to get it. It just isn't going to happen.

    Even my McIntosh MP100 only generates 60dB worth of gain (same with my previous Manley Chinook) and these are phono stages in the $2,000 category. I knew the limitations of the MP100 when I bought it - but I also knew I wouldn't be trying to use phono cartridge with an output less the 0.3mV.
     
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  16. Davey

    Davey I carry the moon inside a silver bag

    Location:
    SF Bay Area, USA
    Turns out the MoFi phono has pretty good input overload margin too, looks like over 24dB at the 40dB gain setting, wonder if they made some updates since the problem you reported with its little brother?
     
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  17. nvilletele

    nvilletele Active Member

    Location:
    New City
    Looking at the Lab Report you cited,

    I get the sense that the StudioPhono may not by itself be the best option for use with my low output Karat.
    However, I would think that it would still be better (or at least no worse), on its own, than the lower gain V90 (again, on its own) that I currently have.

    Is this a reasonable assumption?

    If so, then I think it would still make sense for me to try it out, and if unsatisfactory on its own, try it with the Piccolo.
     
  18. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    If you are going for a whole new phono preamp, there are a handful that a super adjustable and might fit the bill. As others have noted, some came out of the gate with some possible issues. iPhono2 seems to have a good bit of gain, Jasmine or Vincent Pho—these come to mind. Not to discourage your plane, but there are options.
     
  19. Benzion

    Benzion "Cogito, ergo sum" Forum Resident

    Location:
    Brooklyn, NY
    I must ask. Have you tried the MF at all? How do you know you wont like it without trying it?
     
  20. nvilletele

    nvilletele Active Member

    Location:
    New City
    Yes, I tried it, with my Kenwood receiver, and did not find it to work well with the low output Karat cart. I haven't yet tried it with the Technics amp, as I got involved on something else before I completed moving my systems around. I am planning to do that shortly.

    iPhono2 does have a lot of gain, but as others have mentioned, it seems to have a lot of reported equipment failure issues. And for the price, the other two you mentioned, Jasmine and Vincent Pho, seem somewhat better and in the same general price range. But I am open to considering something along these lines, as I realize the cost of the MoFi plus the Piccolo comes out to pretty much the same.

    The Jasmine LP2 seems no longer available (from what I could see) but there is one now on eBay, and there may perhaps be others still around. Seems to have 70db and is stated at suitable for MC from 0.1 to 0.5, so the Karat would fit in there nicely.

    The Pho seems quite good, and its manual states "While MM systems usually deploy a voltage of several mVolts, most MC systems only use 100 μV. Nowadays you often find mixed types as well, they are called high-output MC systems and have a voltage of up to 2.5 mV."

    So I gather the 0.2mV value of the Karat also would be no issue. But there is no gain figure mentioned, only settings for impedance values, under the "Adjustments for MC" and capacitance values, under "Adjustments for MM". I gather from a prior comment that the corresponding gain values can be derived from other figures, but I wouldn't know how to do this, and whether it applies to impedance, capacitance or something else. The capacitance settings and impedance settings use completely different pins to change settings, but still impedance settings in the manual are under MC adjustment section and capacitance settings under MM adjustment settings, further confusing me as to whether these apply only to one type, which seems implied. In any case, while the Pho certainly seems it can handle low output MC carts, the gain level is not clear to me.

    At some point I suppose I will make a decision. Now I guess I am open to considering better units up to around $600, since that would be hardly any more than the MoFi together with the Piccolo which I was already contemplating.

    <sigh>
    <Help?>
     
  21. Ontheone

    Ontheone Drifting Towards the Dead Wax

    Location:
    Indianapolis
    I've had a hard time following and catching up with this thread but it seems like your budgets are reversed - I would be spending 2x on a phono stage compared to what the cart cost. A few hundred dollar phono stage just isn't going to do a high quality LOMC any justice at all. For example, when my Herron VTPH2A was my main phono stage (~$3K) I was using it to run a $750 Hana SL and I felt my ears were getting the most out both components. I think you'd be shocked if you heard some side-by-side comparisons of that DV cart with a ~$2K+ phono stage compared to a $500 stage. Pay more for the phono stage, less for the cart and I'd bet your sound will be much better than vice versa. Just my 2 cents.
     
  22. psulioninks

    psulioninks Forum Resident

    Location:
    Midwest USA
    It looks like most of Vincent's PHO* units top out at 60dB for gain. If you're using a moving coil, capacitance is not really an issue - being able to select various loading resistant values will as this affects the sound from your system as well as the loudness. For example, running my moving coil at 400 ohms on my MP100 creates more output than loading it down at the 50 ohms setting.

    So basically speaking...

    Capacitance = moving magnets cartridges
    Resistance Loading = moving coil cartridges
    Gain = all cartridges
     
  23. Phil Thien

    Phil Thien Forum Resident

    Location:
    Milwaukee, WI
    Yeah but he already owns the cartridge.

    I think he is trying to solve his dilemma without throwing four figures at it.
     
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  24. Davey

    Davey I carry the moon inside a silver bag

    Location:
    SF Bay Area, USA
    Well, I think the problem is that he is has a DV/Karat Ruby cartridge that for all intents is free, since it's been stashed unused for the last 40 years. It was around $275 back in 1980, so maybe a $1000 or so nowadays, maybe $2000, I think Dynavector prices have gone up dramatically in recent times. So he probably doesn't want to invest a pile of cash to find out how good it can be. It may even need to be rebuilt to perform well, that's a long time to sit around, suspension may even be shot by now.
     
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  25. psulioninks

    psulioninks Forum Resident

    Location:
    Midwest USA
    To properly run than cartridge AND stay under $1k...I'd look for something on the used market.
     
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